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| Woodworking (rec.woodworking) Discussion forum covering all aspects of working with wood. All levels of expertise are encouraged to particiapte. |
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#1
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Semi OT Electrical Question
Folks -
I have an old Victorian, Circa 1868.... The tenants trashed it, long story.... Anyway, most of the electric outlets are two prong, rather than grounded.... I would like to put grounded outlets in, but I have only a hot (black) and neutral (white) No separate ground wire.... Would it be safe to install a 3 wire plug and have the ground and neutral common to the white wire? Would this work and be safe? Only having 2 prong outlets has been a PITA, and getting under the house to run separate grounds would be a real bit of work. Would bridging the ground and common terminals also work and be safe with a GFCI outlet? I would appreciate any remarks from those that KNOW and have experience. The last thing I want is a fire.... I was under the house yesterday and found some old andirons.... All of the timber underneath is full dimension stuff, maybe even bigger.... Thanks in advance for any help that can be given.... John Moorhead |
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#2
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Semi OT Electrical Question
On Wed, 07 Apr 2004 03:32:50 +0000, John Moorhead wrote:
Folks - I have an old Victorian, Circa 1868.... The tenants trashed it, long story.... Anyway, most of the electric outlets are two prong, rather than grounded.... I would like to put grounded outlets in, but I have only a hot (black) and neutral (white) No separate ground wire.... Would it be safe to install a 3 wire plug and have the ground and neutral common to the white wire? Would this work and be safe? Only having 2 prong outlets has been a PITA, and getting under the house to run separate grounds would be a real bit of work. Would bridging the ground and common terminals also work and be safe with a GFCI outlet? I would appreciate any remarks from those that KNOW and have experience. The last thing I want is a fire.... NO, _NOT_ safe and don't do it. Electrocution is probably the first concern, fire somewhere after that. -Doug -- "A government that robs Peter to pay Paul can always depend on the support of Paul." - George Bernard Shaw |
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#3
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Semi OT Electrical Question
On Wed, 07 Apr 2004 03:32:50 GMT, "John Moorhead"
wrote: Folks - I have an old Victorian, Circa 1868.... The tenants trashed it, long story.... Anyway, most of the electric outlets are two prong, rather than grounded.... I would like to put grounded outlets in, but I have only a hot (black) and neutral (white) No separate ground wire.... Would it be safe to install a 3 wire plug and have the ground and neutral common to the white wire? Would this work and be safe? Only having 2 prong outlets has been a PITA, and getting under the house to run separate grounds would be a real bit of work. Would bridging the ground and common terminals also work and be safe with a GFCI outlet? snip No. It is not safe nor allowed by code to use a current carrying conductor (neutral) as an equipment grounding conductor (ground). If the neutral were to open downstream, you would have 120 volts on the exterior metal parts of anything connected in that way. Excellent way to get electrocuted. You are allowed to install a GFCI outlet with no ground connection to provide a 3 prong outlet when no ground is available. This is safe because the GFCI will trip if there is any fault current flowing to an external ground (like between your hair dryer and the sink faucet via your arms!). This is not a perfect solution, because you still don't have an actual ground connection which can help eliminate electrical interference to/from electronic equipment. But it is safe and allowed by code. HTH, Paul |
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#4
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Semi OT Electrical Question
You are allowed to install a GFCI outlet with no ground connection to
provide a 3 prong outlet when no ground is available. Yes, it is a 3 prong outlet, but it is the same as breaking the ground off the plug; the ground on the GFCI is not connected to anything. Off hand I can't think of anywhere this distinction would matter, except for a possible nuisance trip. |
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#5
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Semi OT Electrical Question
Neutrals although grounded at the service are not grounds. Reason being that
any voltage drop across conductors is halved in the neutral. ( There are exceptions ) This can be from other loads connected to that neutral. Therefore a neutral can carry a voltage potential at the outlet. NEC now requires any 2 wire outlets not having a ground and being replaced, be done so with GFCIs. This does not ground the device connected but does offer protection from any fault that results in a more than a 5 milliamp difference between the conductors or current detected in the grounded conductor of the device fitted with a 3 prong plug. A separate ground wire is preferred. -- Chipper Wood useours, yours won't work "John Moorhead" wrote in message . com... Folks - I have an old Victorian, Circa 1868.... The tenants trashed it, long story.... Anyway, most of the electric outlets are two prong, rather than grounded.... I would like to put grounded outlets in, but I have only a hot (black) and neutral (white) No separate ground wire.... Would it be safe to install a 3 wire plug and have the ground and neutral common to the white wire? Would this work and be safe? Only having 2 prong outlets has been a PITA, and getting under the house to run separate grounds would be a real bit of work. Would bridging the ground and common terminals also work and be safe with a GFCI outlet? I would appreciate any remarks from those that KNOW and have experience. The last thing I want is a fire.... I was under the house yesterday and found some old andirons.... All of the timber underneath is full dimension stuff, maybe even bigger.... Thanks in advance for any help that can be given.... John Moorhead |
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#6
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Semi OT Electrical Question
John,
A 2 conductor system can be converted to a 3 conductor if done properly. Call in a professional if you don't know how. Done correctly, a GFCI can be used in a 2 conductor system. Adding a GFCI outlet to the circuit makes the circuit safe for you. But it doesn't make it safe for your equipment - you need a ground to make surge suppressors or line filters effective. The NEC requires that three prong receptacles without ground that are protected by GFCI must be labelled as such. Any existing wiring must meet or exceed any local codes and/or the National Electric Code (NEC) that were in effect at time of installation. Any new wiring, including remodeling work, must meet or exceed the current local and/or NEC codes . The 2002 is the current version NEC, but the 2005 NEC code book is scheduled to be released in October, 2004. Also, if you do major work, you may be required to upgrade certain existing portions or all of your system. Check with your local electrical inspector. If you are worried about a fire, call/hire an electrician. Remember insurance won't pay if faulty wiring is found to be the cause. Randy "John Moorhead" wrote in message . com... Folks - I have an old Victorian, Circa 1868.... The tenants trashed it, long story.... Anyway, most of the electric outlets are two prong, rather than grounded.... I would like to put grounded outlets in, but I have only a hot (black) and neutral (white) No separate ground wire.... Would it be safe to install a 3 wire plug and have the ground and neutral common to the white wire? Would this work and be safe? Only having 2 prong outlets has been a PITA, and getting under the house to run separate grounds would be a real bit of work. Would bridging the ground and common terminals also work and be safe with a GFCI outlet? I would appreciate any remarks from those that KNOW and have experience. The last thing I want is a fire.... I was under the house yesterday and found some old andirons.... All of the timber underneath is full dimension stuff, maybe even bigger.... Thanks in advance for any help that can be given.... John Moorhead |
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#7
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Semi OT Electrical Question
"John Moorhead" writes: I have an old Victorian, Circa 1868.... The tenants trashed it, long story.... Anyway, most of the electric outlets are two prong, rather than grounded.... I would like to put grounded outlets in, but I have only a hot (black) and neutral (white) No separate ground wire.... Would it be safe to install a 3 wire plug and have the ground and neutral common to the white wire? NO ! ! Would this work and be safe? NO ! ! Only having 2 prong outlets has been a PITA, and getting under the house to run separate grounds would be a real bit of work. Agreed. Would bridging the ground and common terminals also work and be safe with a GFCI outlet? NO ! ! I would appreciate any remarks from those that KNOW and have experience. The last thing I want is a fire.... You need to find a qualified electrical contractor who specializes in residential re-wire jobs. Up front, this one won't be cheap. My guess is all the existing wiring is loom, knob and tube which just makes the job more difficult. HTH -- Lew S/A: Challenge, The Bullet Proof Boat, (Under Construction in the Southland) Visit: http://home.earthlink.net/~lewhodgett for Pictures |
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#8
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Semi OT Electrical Question
The legal option is simply using the GFCI outlets and putting the sticker on
that says ground is not there. It won't help the surge protector for your electronics but it will mitigate the danger of electrocution. A better fix is to get a ground wire up there but that may be out of your budget.. |
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#9
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Semi OT Electrical Question
Randy A writes:
If you are worried about a fire, call/hire an electrician. Remember insurance won't pay if faulty wiring is found to be the cause. Not necessarily true. State Farm paid off on my fire last year even though the odds were about even between faulty wiring and a sump pump motor wiring fault. Further checking could probably have identified the exact source, but the fire inspector stated the sump pump, with no specifics, was at fault, so they paid. If you have an insurance company that tries to weasel every claim, you're in bad shape to begin with because there is always an "it" that isn't dotted and a "t" that isn't crossed. Time to change companies. Charlie Self "It is not strange... to mistake change for progress." Millard Fillmore |
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#10
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Semi OT Electrical Question
"John Moorhead" wrote in message . com... Folks - I have an old Victorian, Circa 1868.... The tenants trashed it, long story.... Anyway, most of the electric outlets are two prong, rather than grounded.... I would like to put grounded outlets in, but I have only a hot (black) and neutral (white) No separate ground wire.... Would it be safe to install a 3 wire plug and have the ground and neutral common to the white wire? Would this work and be safe? Only having 2 prong outlets has been a PITA, and getting under the house to run separate grounds would be a real bit of work. Would bridging the ground and common terminals also work and be safe with a GFCI outlet? I would appreciate any remarks from those that KNOW and have experience. The last thing I want is a fire.... I was under the house yesterday and found some old andirons.... All of the timber underneath is full dimension stuff, maybe even bigger.... Thanks in advance for any help that can be given.... John Moorhead Is the wiring 'BX' (metal sheath)? If it is, check if you have 120 V between the Hot and the metal box. If there is, the ground is being carried by the cable sheath. What you will want to do is to attach a ground strap to the box, then to the outlet. If there is no ground present, then follow the other advice given. -- Al Reid "It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so." --- Mark Twain |
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#11
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Semi OT Electrical Question
Replacing non-grounded outlets with grounded outlets is a violation of most
electrical codes and hence could impact your insurance if problems arise. Don Dando "John Moorhead" wrote in message . com... Folks - I have an old Victorian, Circa 1868.... The tenants trashed it, long story.... Anyway, most of the electric outlets are two prong, rather than grounded.... I would like to put grounded outlets in, but I have only a hot (black) and neutral (white) No separate ground wire.... Would it be safe to install a 3 wire plug and have the ground and neutral common to the white wire? Would this work and be safe? Only having 2 prong outlets has been a PITA, and getting under the house to run separate grounds would be a real bit of work. Would bridging the ground and common terminals also work and be safe with a GFCI outlet? I would appreciate any remarks from those that KNOW and have experience. The last thing I want is a fire.... I was under the house yesterday and found some old andirons.... All of the timber underneath is full dimension stuff, maybe even bigger.... Thanks in advance for any help that can be given.... John Moorhead |
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#12
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Semi OT Electrical Question
Welll, let's look at this. I'm not addressing code, or what you should do,
just the facts. Danger arises when there is an electrical fault (leakage) from the hot wire or motor winding, etc., of a device to its metallic case. Think electric drill with an insulation failure in the motor winding. For discussion, let's say the case is "connected" to the 120V hot wire. This device will work fine, but you'll be holding the 120V hot in your hand. Even that is fine, UNTIL you touch a "ground", like a water pipe or the case of a "grounded" appliance. At that point, YOU are a current carrying conductor and you will get a healthy (poor choice of word) ZAP. If you are really holding onto things, there is continuing current flow from arm to arm, about the worst way to get it, since it goes by your heart. NOW, there are some errors in some messages. The third wire "ground" is called that because it doesn't carry current. It is the same size as the others so it can carry enough current to trip the breaker involved when a fault occurs. It's there to suck up the fault current IF the neutral wire opens for some reason. BUT, the neutral is the same size wire and connected to the ground at the panel. If it and its connections are good, it can do the same thing. This is the government helping us by demanding a redundant ground path. Yes, there IS current in the neutral and yes, it can be above ground by a small amount (couple volts maybe) if high currents are flowing, BUT never enough to be harmful. Problems arise if the neutral is not well connected to ground at the box.. I've NEVER seen this happen in my 62 years, but I HAVE seen a commercial electrician switch hot and ground, making a bunch of equipment cases 120V hot! Imagine the spark when I connected a signal cable from this equipment to something else that was plugged into an outlet that was properly wired! Thank heavens I didn't pick up the grounded device while holding the metal connector on the cable! At first thought, you might ask why not just connect neutral to the metal tool case and be done with it. That would work, AS LONG as the outlets and plugs were properly polarized (different width prongs) and connected. Unfortunately, old plugs were not polarized and newer ones can be miswired. Remember when "double insulated" tools were the rage? That was an intermediate stage of development during which two insulation systems were used. One was the regular motor insulation and the other was the plastic case of the tool. This is MUCH better than the two wire metal tool. Most cheap table radios with tubes had no transformer and could easily get their chassis hot to ground. In this case, the user was protected only by the case and knobs! If you followed the above, you can see the temptation to use the neutral as a ground. In fact, it would work fine and be safe, UNTIL you had a neutral wire fault, putting your device above ground and making it very dangerous! The GFI outlet is the right answer, unless you can pull new wire. It should be said here that a device needing considerable power plugged into an outlet with a serious neutral fault would not work properly, because of the voltage drop across the fault, so you might have some warning. A device that drew very little current might work well, however, since the drop would be small, but then a fault could occur to cause more current to flow, burning out the fault and leaving the case hot and the device seemingly off. Bad News! I'd try to get good hookups in kitchens and laundry areas, but your bedlamp and table radio don't have many dangers, partly because they are not near grounded metal, usually. Same for TVs, etc. A shop with a damp dirt floor needs protection, especially if you are barefooted. The hand to hand shock is the most likely and most dangerous. The hand to foot shock tends to be mitigated by non conductive shoes and dry floors. Shocks in your left arm are more dangerous than in your right, because of heart nerve location. Let me know if anything above is misstated or confusing. Wilson "Chipper Wood" wrote in message ... Neutrals although grounded at the service are not grounds. Reason being that any voltage drop across conductors is halved in the neutral. ( There are exceptions ) This can be from other loads connected to that neutral. Therefore a neutral can carry a voltage potential at the outlet. NEC now requires any 2 wire outlets not having a ground and being replaced, be done so with GFCIs. This does not ground the device connected but does offer protection from any fault that results in a more than a 5 milliamp difference between the conductors or current detected in the grounded conductor of the device fitted with a 3 prong plug. A separate ground wire is preferred. -- Chipper Wood useours, yours won't work "John Moorhead" wrote in message . com... Folks - I have an old Victorian, Circa 1868.... The tenants trashed it, long story.... Anyway, most of the electric outlets are two prong, rather than grounded.... I would like to put grounded outlets in, but I have only a hot (black) and neutral (white) No separate ground wire.... Would it be safe to install a 3 wire plug and have the ground and neutral common to the white wire? Would this work and be safe? Only having 2 prong outlets has been a PITA, and getting under the house to run separate grounds would be a real bit of work. Would bridging the ground and common terminals also work and be safe with a GFCI outlet? I would appreciate any remarks from those that KNOW and have experience. The last thing I want is a fire.... I was under the house yesterday and found some old andirons.... All of the timber underneath is full dimension stuff, maybe even bigger.... Thanks in advance for any help that can be given.... John Moorhead |
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#13
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Semi OT Electrical Question
What you said is reasonable EXCEPT
The electrical code is extremely conservative, but that allows a lot of us to be still be alive and our houses still standing after doing dumb things. Since we will continue to do dumb things, it is best to leave the redundency there. Houses existed long before grounds were mandated, and continue to exist; but a separate ground is a redundency that significantly increases safety. My dryer has no ground (technically, practically it has no neutral) so 7.5a is available to any one touching bare metal on it. No one has been hurt, in fact maybe no one has been hurt on the millions of similar dryers, but wouldn't it be nicer to eliminate the possibility by separating the ground and neutral? Probably the worst aspect of the OP's idea is that a user would have no idea it was done, and would think the grounded conductor really was a grounded conductor rather than a grounding conductor (yes, those are the correct names). If he then does something dumb, there is no safety net. |
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#14
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Semi OT Electrical Question
My
dryer has no ground (technically, practically it has no neutral) That exemption in the code (dryers and ranges) started in WWII to save copper. A couple code cycles ago the NFPA decided the war was finally over and they made these circuits conform to the rest of article 250 with a separate ground and neutral. You will now see 4 prong receptacles being installed there. I suppose the reason we never piled up bodies is because these were 30-50a circuits with very small 120v loads, if one was there at all. |
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#16
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Semi OT Electrical Question
"Toller" wrote in message ... Houses existed long before grounds were mandated, and continue to exist; but a separate ground is a redundency that significantly increases safety. My dryer has no ground (technically, practically it has no neutral) so 7.5a is available to any one touching bare metal on it. No one has been hurt, in fact maybe no one has been hurt on the millions of similar dryers, but wouldn't it be nicer to eliminate the possibility by separating the ground and neutral? Consider the electrical devices used in the average home. Most would be relatively safe without grounding. A small point on your skin generally has a resistance of about 10,000 ohms. touching a 120 v. connection would draw only about 1/10 of an amp. in current if you were also in contact with a grounded item. Translated, that's about 1 watt of power divided across 4 to 5 feet of ones body. It would cause a definite reaction, but no damage. Not being in contact with a ground on a wooden floor, It might not even be detectable. However a firm grip on a faulty all metal drill handle not properly grounded and standing on damp grass, This could be a lethal situation as the trigger switch is pulled. Simple lamps have the possibility to become connected to the outer socket. There is usually only a paper sleeve separating the metal case from the screw shell. In a few years and using over 60 watt lamps the paper all but disintegrates. This is almost never detected by the user. Insurance companies reserve the right to compensation or denial of claims resulting from willful or deliberate negligence. Everything can become defective over time. Normally a faulty deteriorated electrical connection inside a wall box is not negligent. Pennies behind fuses or a frayed or otherwise defective extension cord used even temporarily across a floor if proven to be an accident cause could be reason to deny a claim. -- Chipper Wood useours, yours won't work |
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#17
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Semi OT Electrical Question
In article , "Toller" wrote:
You are allowed to install a GFCI outlet with no ground connection to provide a 3 prong outlet when no ground is available. Yes, it is a 3 prong outlet, but it is the same as breaking the ground off the plug; the ground on the GFCI is not connected to anything. Off hand I can't think of anywhere this distinction would matter, That was explained in the part that you snipped: You are allowed to install a GFCI outlet with no ground connection to provide a 3 prong outlet when no ground is available. This is safe because the GFCI will trip if there is any fault current flowing to an external ground (like between your hair dryer and the sink faucet via your arms!). except for a possible nuisance trip. Dunno about you... but IMO in the situation described above, it's much more of a nuisance if it does *not* trip... -- Regards, Doug Miller (alphageek-at-milmac-dot-com) For a copy of my TrollFilter for NewsProxy/Nfilter, send email to autoresponder at filterinfo-at-milmac-dot-com |
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#18
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Semi OT Electrical Question
....
You are allowed to install a GFCI outlet with no ground connection to provide a 3 prong outlet when no ground is available. This is safe because the GFCI will trip if there is any fault current flowing to an external ground (like between your hair dryer and the sink faucet via your arms!). May I ask your source of that information? I would like to verify it. It's true you can use a GFCI on a 2-wire ckt, with a 2-prong outlet, but NOT in order to provide a 3-prong outlet!! The 3-wire system provides a level of protection that is far superior to 2-wire, and ANYONE could look at that sort of a setup and think it's safe to use equipment that REQUIRES the third wire! Also, everything from TVs to computers, surge suppressors, telephone, stereos, any modern electronic equipment, will very likely experience noise and interference problems, and surge protection components as provided IN most electronic equipment, would be unable to function, and any external surge/power protectors would be nothing but useless power bars with no function. The place would be a real pain to most electronic equipment on the market today. Technically, onle Class 2, 2-wire equipment would be acceptable to run on that setup. A possible solution might be to: -- Put in your own ground rod in a location where it can be run into the breaker box? -- The meter must have a ground: Can that be tapped into, say, at the service entrance? -- How about a metal water line? Caution: PROVE it's a grounded metal, not just looks like it is. Anyone in the business can tell you quickly. Pop & his two cents |
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#19
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Semi OT Electrical Question
Pop Rivet wrote:
... You are allowed to install a GFCI outlet with no ground connection to provide a 3 prong outlet when no ground is available. This is safe because the GFCI will trip if there is any fault current flowing to an external ground (like between your hair dryer and the sink faucet via your arms!). May I ask your source of that information? I would like to verify it. It's Check the NEC. Yes, this is the recommended way to provide a 3-prong outlet on a non-grounded circuit. Note: it is *supposed* to be marked so that you can tell it is not providing a ground. The idea is, at least you won't eletrocute yourself or somebody this way. If it were my old house, I'd rewire it. Yes it's a pain, but worth it in the long run. Bill Ranck Blacksburg, Va. |
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#20
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Semi OT Electrical Question
May I ask your source of that information? I would like to verify it.
The National Electric Code 406.3(D)(3) 3) Nongrounding-Type Receptacles. Where grounding means does not exist in the receptacle enclosure, the installation shall comply with (a), (b), or (c). (a) A nongrounding-type receptacle(s) shall be permitted to be replaced with another nongrounding-type receptacle(s). (b) A nongrounding-type receptacle(s) shall be permitted to be replaced with a ground-fault circuit interrupter-type of receptacle(s). These receptacles shall be marked €œNo Equipment Ground.€? An equipment grounding conductor shall not be connected from the ground-fault circuit-interrupter-type receptacle to any outlet supplied from the ground-fault circuit-interrupter receptacle. (c) A nongrounding-type receptacle(s) shall be permitted to be replaced with a grounding-type receptacle(s) where supplied through a ground-fault circuit interrupter. Grounding-type receptacles supplied through the ground-fault circuit interrupter shall be marked €œGFCI Protected€? and €œNo Equipment Ground.€? An equipment grounding conductor shall not be connected between the grounding-type receptacles. |
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#21
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Semi OT Electrical Question
....
May I ask your source of that information? I would like to verify it. It's Check the NEC. Yes, this is the recommended way to provide a 3-prong outlet on a non-grounded circuit. Note: it is *supposed* to be marked so that you can tell it is not providing a ground. The idea is, at least you won't eletrocute yourself or somebody this way. .... No, YOU check the NEC; you missed something. I already know what it says. Where you went off track was in failing to mention that such a situation can ONLY exist IF it is marked! There are also restrictions on HOW the outlet can be so marked, and I highly doubt that you could get ANY inspector to accept an entire domain wired that way. Your advice sounded to the contrary. If you don't know about the marking rules, check your NEC. And then check your locals. You must meet the more stringent of the two (or three, or four depending on where you live)! NEC is only a minimum requirement in the event of no other coverage. Any local code can exceed but not decede, the NEC. Almost all do. It seems like you mentioned NY? Hell in this state, you can hardly put water in a toilet if there's an outlet within a hundred feet! It's union's paradise! Now, if you also go to your local code enforcement, you are highly likely in most localities to find that you would NOT be allowed to use that wiring method. |
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#22
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Semi OT Electrical Question
"Greg" wrote in message ... May I ask your source of that information? I would like to verify it. The National Electric Code 406.3(D)(3) 3) Nongrounding-Type Receptacles. Where grounding means does not exist in the receptacle enclosure, the installation shall comply with (a), (b), or (c). (a) A nongrounding-type receptacle(s) shall be permitted to be replaced with another nongrounding-type receptacle(s). (b) A nongrounding-type receptacle(s) shall be permitted to be replaced with a ground-fault circuit interrupter-type of receptacle(s). These receptacles shall be marked "No Equipment Ground." An equipment grounding conductor shall not be connected from the ground-fault circuit-interrupter-type receptacle to any outlet supplied from the ground-fault circuit-interrupter receptacle. (c) A nongrounding-type receptacle(s) shall be permitted to be replaced with a grounding-type receptacle(s) where supplied through a ground-fault circuit interrupter. Grounding-type receptacles supplied through the ground-fault circuit interrupter shall be marked "GFCI Protected" and "No Equipment Ground." An equipment grounding conductor shall not be connected between the grounding-type receptacles. I'm sorry, but there can be no debate of a subject such as this in the vacuum of one short section of the overall code. As in any technical regulation, the entire context of all related sections and paras must be considered. Everything here is true: but it is not in complete context without the remaining relevant components of the regulation. To be complete, every relevant section/para must be considered. Then, and probably more importantly, local codes must be considered; the NEC is only a starting point and a good reference. It is not the final word as it may (and often is) much more lenient than local codes. You cannot wire simply to the NEC. Pop Pop |
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#23
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Semi OT Electrical Question
"Pop Rivet" wrote in message ... ... May I ask your source of that information? I would like to verify it. It's Check the NEC. Yes, this is the recommended way to provide a 3-prong outlet on a non-grounded circuit. Note: it is *supposed* to be marked so that you can tell it is not providing a ground. The idea is, at least you won't eletrocute yourself or somebody this way. ... No, YOU check the NEC; you missed something. I already know what it says. Where you went off track was in failing to mention that such a situation can ONLY exist IF it is marked! There are also restrictions on HOW the outlet can be so marked, and I highly doubt that you could get ANY inspector to accept an entire domain wired that way. Your advice sounded to the contrary. If you don't know about the marking rules, check your NEC. And then check your locals. You must meet the more stringent of the two (or three, or four depending on where you live)! NEC is only a minimum requirement in the event of no other coverage. Any local code can exceed but not decede, the NEC. Almost all do. It seems like you mentioned NY? Hell in this state, you can hardly put water in a toilet if there's an outlet within a hundred feet! It's union's paradise! Now, if you also go to your local code enforcement, you are highly likely in most localities to find that you would NOT be allowed to use that wiring method. NO, the idea is that it allowed them to "grandfather" in old buildings where current regulations would create a severe hardship. You would not get a permet to use this method on new construction. |
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#24
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Semi OT Electrical Question
I'm sorry, but there can be no debate of a subject such as this in the
vacuum of one short section of the overall code. I suppose I could post all of article 406 but that is the only relevant part. Certainly a local AHJ can spin this any way he likes but if you are in a state like Florida that has eliminated all local rules as part of a unified state building code and that code accepts the NEC, unaltered that is all there is to say about the subject. You CAN replace an ungrounded receptacle with a GFCI receptacle (or use a GFCI breaker) and all down stream receptacles can be of the grounding type ... as long as your AHJ follows the NEC. Your mileage may vary if you are in a locality that does not accept the NEC and there is a very good chance this doesn't apply outside of the US. People in Europe don't use GFCIs, they have an RCD. |
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#25
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Semi OT Electrical Question
Pop it is very specific that this is only to "replace" an existing receptacle
where an equipment grounding path is not present. If you are adding a new circuit it must be with a grounded wiring method. |
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#26
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Semi OT Electrical Question
Chipper Wood wrote:
touching a 120 v. connection would draw only about 1/10 of an amp. in current if you were also in contact with a grounded item. Translated, that's about 1 watt of power divided across 4 to 5 feet of ones body. It would cause a definite reaction, but no damage. Actually, this amount of current is far from harmless and may be fatal. See http://www.cdc.gov/niosh/docs/2002-123/2002-123b.html, http://www.tpub.com/content/fc/14098/css/14098_34.htm, and http://www.physics.ohio-state.edu/~p616/safety/fatal_current.html. -- -- Steve |
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#27
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Semi OT Electrical Question
Steve,
Using the first site you posted, Between 5 and 100 milliamps is what I was referring to. Milli as in millennium = 1/1000 100/1000 = 1/10 amp. This will get your attention and cause a reflex. From experience, 277 v. is about 2 1/2 times this amount and is definitely painful at just a touch. Multiply the contact by the area of holding a metal device such as wire strippers firmly and at 120 v. there is a disabling or lethal current present. IMHO, There is nothing about contact with household electric current that can be considered 'harmless' and I hope that no one derived that conclusion from what I wrote. -- Chipper Wood useours, yours won't work "Steve Dunbar" wrote in message ... Chipper Wood wrote: touching a 120 v. connection would draw only about 1/10 of an amp. in current if you were also in contact with a grounded item. Translated, that's about 1 watt of power divided across 4 to 5 feet of ones body. It would cause a definite reaction, but no damage. Actually, this amount of current is far from harmless and may be fatal. See http://www.cdc.gov/niosh/docs/2002-123/2002-123b.html, http://www.tpub.com/content/fc/14098/css/14098_34.htm, and http://www.physics.ohio-state.edu/~p616/safety/fatal_current.html. -- -- Steve |
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#28
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Semi OT Electrical Question
Welll, let's look at this. I'm not addressing code, or what you should do,
just the facts. Danger arises when there is an electrical fault (leakage) from the hot wire or motor winding, etc., of a device to its metallic case. Think electric drill with an insulation failure in the motor winding. For discussion, let's say the case is "connected" to the 120V hot wire. This device will work fine, but you'll be holding the 120V hot in your hand. Even that is fine, UNTIL you touch a "ground", like a water pipe or the case of a "grounded" appliance. At that point, YOU are a current carrying conductor and you will get a healthy (poor choice of word) ZAP. If you are really holding onto things, there is continuing current flow from arm to arm, about the worst way to get it, since it goes by your heart. NOW, there are some errors in some messages. The third wire "ground" is called that because it doesn't carry current. It is the same size as the others so it can carry enough current to trip the breaker involved when a fault occurs. It's there to suck up the fault current IF the neutral wire opens for some reason. BUT, the neutral is the same size wire and connected to the ground at the panel. If it and its connections are good, it can do the same thing. This is the government helping us by demanding a redundant ground path. Yes, there IS current in the neutral and yes, it can be above ground by a small amount (couple volts maybe) if high currents are flowing, BUT never enough to be harmful. Problems arise if the neutral is not well connected to ground at the box.. I've NEVER seen this happen in my 62 years, but I HAVE seen a commercial electrician switch hot and ground, making a bunch of equipment cases 120V hot! Imagine the spark when I connected a signal cable from this equipment to something else that was plugged into an outlet that was properly wired! Thank heavens I didn't pick up the grounded device while holding the metal connector on the cable! At first thought, you might ask why not just connect neutral to the metal tool case and be done with it. That would work, AS LONG as the outlets and plugs were properly polarized (different width prongs) and connected. Unfortunately, old plugs were not polarized and newer ones can be miswired. Remember when "double insulated" tools were the rage? That was an intermediate stage of development during which two insulation systems were used. One was the regular motor insulation and the other was the plastic case of the tool. This is MUCH better than the two wire metal tool. Most cheap table radios with tubes had no transformer and could easily get their chassis hot to ground. In this case, the user was protected only by the case and knobs! If you followed the above, you can see the temptation to use the neutral as a ground. In fact, it would work fine and be safe, UNTIL you had a neutral wire fault, putting your device above ground and making it very dangerous! The GFI outlet is the right answer, unless you can pull new wire. It should be said here that a device needing considerable power plugged into an outlet with a serious neutral fault would not work properly, because of the voltage drop across the fault, so you might have some warning. A device that drew very little current might work well, however, since the drop would be small, but then a fault could occur to cause more current to flow, burning out the fault and leaving the case hot and the device seemingly off. Bad News! I'd try to get good hookups in kitchens and laundry areas, but your bedlamp and table radio don't have many dangers, partly because they are not near grounded metal, usually. Same for TVs, etc. A shop with a damp dirt floor needs protection, especially if you are barefooted. The hand to hand shock is the most likely and most dangerous. The hand to foot shock tends to be mitigated by non conductive shoes and dry floors. Shocks in your left arm are more dangerous than in your right, because of heart nerve location. Let me know if anything above is misstated or confusing. Wilson "John Moorhead" wrote in message . com... Folks - I have an old Victorian, Circa 1868.... The tenants trashed it, long story.... Anyway, most of the electric outlets are two prong, rather than grounded.... I would like to put grounded outlets in, but I have only a hot (black) and neutral (white) No separate ground wire.... Would it be safe to install a 3 wire plug and have the ground and neutral common to the white wire? Would this work and be safe? Only having 2 prong outlets has been a PITA, and getting under the house to run separate grounds would be a real bit of work. Would bridging the ground and common terminals also work and be safe with a GFCI outlet? I would appreciate any remarks from those that KNOW and have experience. The last thing I want is a fire.... I was under the house yesterday and found some old andirons.... All of the timber underneath is full dimension stuff, maybe even bigger.... Thanks in advance for any help that can be given.... John Moorhead |
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#29
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Semi OT Electrical Question
Welll, let's look at this. I'm not addressing code, or what you should do,
just the facts. Danger arises when there is an electrical fault (leakage) from the hot wire or motor winding, etc., of a device to its metallic case. Think electric drill with an insulation failure in the motor winding. For discussion, let's say the case is "connected" to the 120V hot wire. This device will work fine, but you'll be holding the 120V hot in your hand. Even that is fine, UNTIL you touch a "ground", like a water pipe or the case of a "grounded" appliance. At that point, YOU are a current carrying conductor and you will get a healthy (poor choice of word) ZAP. If you are really holding onto things, there is continuing current flow from arm to arm, about the worst way to get it, since it goes by your heart. NOW, there are some errors in some messages. The third wire "ground" is called that because it doesn't carry current. It is the same size as the others so it can carry enough current to trip the breaker involved when a fault occurs. It's there to suck up the fault current IF the neutral wire opens for some reason. BUT, the neutral is the same size wire and connected to the ground at the panel. If it and its connections are good, it can do the same thing. This is the government helping us by demanding a redundant ground path. Yes, there IS current in the neutral and yes, it can be above ground by a small amount (couple volts maybe) if high currents are flowing, BUT never enough to be harmful. Problems arise if the neutral is not well connected to ground at the box.. I've NEVER seen this happen in my 62 years, but I HAVE seen a commercial electrician switch hot and ground, making a bunch of equipment cases 120V hot! Imagine the spark when I connected a signal cable from this equipment to something else that was plugged into an outlet that was properly wired! Thank heavens I didn't pick up the grounded device while holding the metal connector on the cable! At first thought, you might ask why not just connect neutral to the metal tool case and be done with it. That would work, AS LONG as the outlets and plugs were properly polarized (different width prongs) and connected. Unfortunately, old plugs were not polarized and newer ones can be miswired. Remember when "double insulated" tools were the rage? That was an intermediate stage of development during which two insulation systems were used. One was the regular motor insulation and the other was the plastic case of the tool. This is MUCH better than the two wire metal tool. Most cheap table radios with tubes had no transformer and could easily get their chassis hot to ground. In this case, the user was protected only by the case and knobs! If you followed the above, you can see the temptation to use the neutral as a ground. In fact, it would work fine and be safe, UNTIL you had a neutral wire fault, putting your device above ground and making it very dangerous! The GFI outlet is the right answer, unless you can pull new wire. It should be said here that a device needing considerable power plugged into an outlet with a serious neutral fault would not work properly, because of the voltage drop across the fault, so you might have some warning. A device that drew very little current might work well, however, since the drop would be small, but then a fault could occur to cause more current to flow, burning out the fault and leaving the case hot and the device seemingly off. Bad News! I'd try to get good hookups in kitchens and laundry areas, but your bedlamp and table radio don't have many dangers, partly because they are not near grounded metal, usually. Same for TVs, etc. A shop with a damp dirt floor needs protection, especially if you are barefooted. The hand to hand shock is the most likely and most dangerous. The hand to foot shock tends to be mitigated by non conductive shoes and dry floors. Shocks in your left arm are more dangerous than in your right, because of heart nerve location. Let me know if anything above is misstated or confusing. Wilson "John Moorhead" wrote in message . com... Folks - I have an old Victorian, Circa 1868.... The tenants trashed it, long story.... Anyway, most of the electric outlets are two prong, rather than grounded.... I would like to put grounded outlets in, but I have only a hot (black) and neutral (white) No separate ground wire.... Would it be safe to install a 3 wire plug and have the ground and neutral common to the white wire? Would this work and be safe? Only having 2 prong outlets has been a PITA, and getting under the house to run separate grounds would be a real bit of work. Would bridging the ground and common terminals also work and be safe with a GFCI outlet? I would appreciate any remarks from those that KNOW and have experience. The last thing I want is a fire.... I was under the house yesterday and found some old andirons.... All of the timber underneath is full dimension stuff, maybe even bigger.... Thanks in advance for any help that can be given.... John Moorhead |
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#30
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Semi OT Electrical Question
Welll, let's look at this. I'm not addressing code, or what you should do,
just the facts. Danger arises when there is an electrical fault (leakage) from the hot wire or motor winding, etc., of a device to its metallic case. Think electric drill with an insulation failure in the motor winding. For discussion, let's say the case is "connected" to the 120V hot wire. This device will work fine, but you'll be holding the 120V hot in your hand. Even that is fine, UNTIL you touch a "ground", like a water pipe or the case of a "grounded" appliance. At that point, YOU are a current carrying conductor and you will get a healthy (poor choice of word) ZAP. If you are really holding onto things, there is continuing current flow from arm to arm, about the worst way to get it, since it goes by your heart. NOW, there are some errors in some messages. The third wire "ground" is called that because it doesn't carry current. It is the same size as the others so it can carry enough current to trip the breaker involved when a fault occurs. It's there to suck up the fault current IF the neutral wire opens for some reason. BUT, the neutral is the same size wire and connected to the ground at the panel. If it and its connections are good, it can do the same thing. This is the government helping us by demanding a redundant ground path. Yes, there IS current in the neutral and yes, it can be above ground by a small amount (couple volts maybe) if high currents are flowing, BUT never enough to be harmful. Problems arise if the neutral is not well connected to ground at the box.. I've NEVER seen this happen in my 62 years, but I HAVE seen a commercial electrician switch hot and ground, making a bunch of equipment cases 120V hot! Imagine the spark when I connected a signal cable from this equipment to something else that was plugged into an outlet that was properly wired! Thank heavens I didn't pick up the grounded device while holding the metal connector on the cable! At first thought, you might ask why not just connect neutral to the metal tool case and be done with it. That would work, AS LONG as the outlets and plugs were properly polarized (different width prongs) and connected. Unfortunately, old plugs were not polarized and newer ones can be miswired. Remember when "double insulated" tools were the rage? That was an intermediate stage of development during which two insulation systems were used. One was the regular motor insulation and the other was the plastic case of the tool. This is MUCH better than the two wire metal tool. Most cheap table radios with tubes had no transformer and could easily get their chassis hot to ground. In this case, the user was protected only by the case and knobs! If you followed the above, you can see the temptation to use the neutral as a ground. In fact, it would work fine and be safe, UNTIL you had a neutral wire fault, putting your device above ground and making it very dangerous! The GFI outlet is the right answer, unless you can pull new wire. It should be said here that a device needing considerable power plugged into an outlet with a serious neutral fault would not work properly, because of the voltage drop across the fault, so you might have some warning. A device that drew very little current might work well, however, since the drop would be small, but then a fault could occur to cause more current to flow, burning out the fault and leaving the case hot and the device seemingly off. Bad News! I'd try to get good hookups in kitchens and laundry areas, but your bedlamp and table radio don't have many dangers, partly because they are not near grounded metal, usually. Same for TVs, etc. A shop with a damp dirt floor needs protection, especially if you are barefooted. The hand to hand shock is the most likely and most dangerous. The hand to foot shock tends to be mitigated by non conductive shoes and dry floors. Shocks in your left arm are more dangerous than in your right, because of heart nerve location. Let me know if anything above is misstated or confusing. Wilson "John Moorhead" wrote in message . com... Folks - I have an old Victorian, Circa 1868.... The tenants trashed it, long story.... Anyway, most of the electric outlets are two prong, rather than grounded.... I would like to put grounded outlets in, but I have only a hot (black) and neutral (white) No separate ground wire.... Would it be safe to install a 3 wire plug and have the ground and neutral common to the white wire? Would this work and be safe? Only having 2 prong outlets has been a PITA, and getting under the house to run separate grounds would be a real bit of work. Would bridging the ground and common terminals also work and be safe with a GFCI outlet? I would appreciate any remarks from those that KNOW and have experience. The last thing I want is a fire.... I was under the house yesterday and found some old andirons.... All of the timber underneath is full dimension stuff, maybe even bigger.... Thanks in advance for any help that can be given.... John Moorhead |
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#31
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Semi OT Electrical Question
Welll, let's look at this. I'm not addressing code, or what you should do,
just the facts. Danger arises when there is an electrical fault (leakage) from the hot wire or motor winding, etc., of a device to its metallic case. Think electric drill with an insulation failure in the motor winding. For discussion, let's say the case is "connected" to the 120V hot wire. This device will work fine, but you'll be holding the 120V hot in your hand. Even that is fine, UNTIL you touch a "ground", like a water pipe or the case of a "grounded" appliance. At that point, YOU are a current carrying conductor and you will get a healthy (poor choice of word) ZAP. If you are really holding onto things, there is continuing current flow from arm to arm, about the worst way to get it, since it goes by your heart. NOW, there are some errors in some messages. The third wire "ground" is called that because it doesn't carry current. It is the same size as the others so it can carry enough current to trip the breaker involved when a fault occurs. It's there to suck up the fault current IF the neutral wire opens for some reason. BUT, the neutral is the same size wire and connected to the ground at the panel. If it and its connections are good, it can do the same thing. This is the government helping us by demanding a redundant ground path. Yes, there IS current in the neutral and yes, it can be above ground by a small amount (couple volts maybe) if high currents are flowing, BUT never enough to be harmful. Problems arise if the neutral is not well connected to ground at the box.. I've NEVER seen this happen in my 62 years, but I HAVE seen a commercial electrician switch hot and ground, making a bunch of equipment cases 120V hot! Imagine the spark when I connected a signal cable from this equipment to something else that was plugged into an outlet that was properly wired! Thank heavens I didn't pick up the grounded device while holding the metal connector on the cable! At first thought, you might ask why not just connect neutral to the metal tool case and be done with it. That would work, AS LONG as the outlets and plugs were properly polarized (different width prongs) and connected. Unfortunately, old plugs were not polarized and newer ones can be miswired. Remember when "double insulated" tools were the rage? That was an intermediate stage of development during which two insulation systems were used. One was the regular motor insulation and the other was the plastic case of the tool. This is MUCH better than the two wire metal tool. Most cheap table radios with tubes had no transformer and could easily get their chassis hot to ground. In this case, the user was protected only by the case and knobs! If you followed the above, you can see the temptation to use the neutral as a ground. In fact, it would work fine and be safe, UNTIL you had a neutral wire fault, putting your device above ground and making it very dangerous! The GFI outlet is the right answer, unless you can pull new wire. It should be said here that a device needing considerable power plugged into an outlet with a serious neutral fault would not work properly, because of the voltage drop across the fault, so you might have some warning. A device that drew very little current might work well, however, since the drop would be small, but then a fault could occur to cause more current to flow, burning out the fault and leaving the case hot and the device seemingly off. Bad News! I'd try to get good hookups in kitchens and laundry areas, but your bedlamp and table radio don't have many dangers, partly because they are not near grounded metal, usually. Same for TVs, etc. A shop with a damp dirt floor needs protection, especially if you are barefooted. The hand to hand shock is the most likely and most dangerous. The hand to foot shock tends to be mitigated by non conductive shoes and dry floors. Shocks in your left arm are more dangerous than in your right, because of heart nerve location. Let me know if anything above is misstated or confusing. Wilson "John Moorhead" wrote in message . com... Folks - I have an old Victorian, Circa 1868.... The tenants trashed it, long story.... Anyway, most of the electric outlets are two prong, rather than grounded.... I would like to put grounded outlets in, but I have only a hot (black) and neutral (white) No separate ground wire.... Would it be safe to install a 3 wire plug and have the ground and neutral common to the white wire? Would this work and be safe? Only having 2 prong outlets has been a PITA, and getting under the house to run separate grounds would be a real bit of work. Would bridging the ground and common terminals also work and be safe with a GFCI outlet? I would appreciate any remarks from those that KNOW and have experience. The last thing I want is a fire.... I was under the house yesterday and found some old andirons.... All of the timber underneath is full dimension stuff, maybe even bigger.... Thanks in advance for any help that can be given.... John Moorhead |
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#32
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Semi OT Electrical Question
Pop Rivet wrote:
"Pop Rivet" wrote in message ... ... a 3-prong outlet on a non-grounded circuit. Note: it is *supposed* to be marked so that you can tell it is not ^^^^^^^^^^^^^^^^^^^^^^^ providing a ground. The idea is, at least you won't eletrocute yourself or somebody this way. ... No, YOU check the NEC; you missed something. I already know what it says. Where you went off track was in failing to mention that such a situation can ONLY exist IF it is marked! There are also restrictions on HOW the outlet Notice that part up there that I just underlined? I said it is supposed to be marked. I also said, in a part you snipped out, that I would rewire the whole thing if it were me. can be so marked, and I highly doubt that you could get ANY inspector to accept an entire domain wired that way. Your advice sounded to the contrary. If you don't know about the marking rules, check your NEC. And NEC allows it when replacing old recepticles, no question. Now, local laws can be more strict, but I don't know where the OP is or what his local rules might or might not be. And of course, the local inspector is the final authority. Bill Ranck Blacksburg, Va. |
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#33
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Semi OT Electrical Question
On Thu, 08 Apr 2004 09:26:44 GMT, "Wilson"
wrote: |Welll, let's look at this. I'm not addressing code, or what you should do, |just the facts. | |Danger arises when there is an electrical fault (leakage) from the hot wire |or motor winding, etc., of a device to its metallic case. Think electric |drill with an insulation failure in the motor winding. For discussion, |let's say the case is "connected" to the 120V hot wire. This device will |work fine, but you'll be holding the 120V hot in your hand. Even that is |fine, UNTIL you touch a "ground", like a water pipe or the case of a |"grounded" appliance. At that point, YOU are a current carrying conductor |and you will get a healthy (poor choice of word) ZAP. If you are really |holding onto things, there is continuing current flow from arm to arm, about |the worst way to get it, since it goes by your heart. Exactly. Let me offer this personal example. In my youth I worked in an automotive machine shop. The shop was in an old building where all of the 110V (standard V in that era) wiring was two-wire, i.e. no grounding conductor. We installed an engine balancer and the wiring associated with that equipment was brought up to code so it included some three-wire outlets. I was the only person qualified to run the balancing equipment and the rules were that accessories were to remain at the balancing station and not to be used elsewhere in the shop. One day I was balancing a crankshaft/flywheel/clutch plate assembly and needed to drill a lightening hole in the clutch plate. The bosses that centered the coil springs had extra material so the process was to use reach through the middle of the spring with a 1/2" drill bit and drill into the boss to take out some weight. Since the assembly was resting horizontally on a set of precision low drag bearings it was necessary to get a real firm grip on it to keep it from turning and to apply the necessary force to drill the hole. So I grabbed the far side of the ring gear with my left hand, cradled the near side in the crook of my left elbow and with my right hand stuck the drill bit, mounted in a heavy duty B&D or Milwaukee (I forget which) 1/2 drill motor into the hole and pulled the trigger. The shock I received was the worse I've ever experienced and after my machine shop days I went into EE and between that and ham radio I've been shocked many times. Since I'm still kicking I surmise that the current was below the critical current that can cause fibrillation and the point at which you can't let go. When I recovered I discovered that some son of a bitch had used the drill motor elsewhere in the shop and when he couldn't plug it in, had cut off the ground pin on the connector. |
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#34
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Semi OT Electrical Question
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#35
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Semi OT Electrical Question
For the sake of discussion, Most of this post is true. However there are
some statements that I do not totally agree with in opinion. Danger arises when there is an electrical fault (leakage) from the hot wire or motor winding, etc., of a device to its metallic case. Any path for an electric potential to be transferred to a person be it metal, water or otherwise is a danger. , the neutral is the same size wire and connected to the ground at the panel. If it and its connections are good, it can do the same thing. Neutrals are current carrying conductors. A poor or open connection can induce up to the full potential voltage on it. Problems arise if the neutral is not well connected to ground at the box. Neutrals are bonded to ground at the service to insure incidental voltages induced in any circuit have a path to ground and not transferred to all the wiring. ( Lightning strikes to a service or other conductor as an example.) I've NEVER seen this happen in my 62 years. In my experience, overheated connection failures are about 80% in neutrals. Even on grounded device plugs. Never knew why.... BUT This is the government helping us by demanding a redundant ground path. The safety codes and rules are determined by tradesmen, fire officials, engineers and insurance companies. People directly involved. The government only tries to enforce them. Most cheap table radios with tubes had no transformer and could easily get their chassis hot to ground. In many this was done intentionally as one supply wire was deliberately connected to the 'isolated' chassis. It should be said here that a device needing considerable power plugged into an outlet with a serious neutral fault would not work properly, because of the voltage drop across the fault, so you might have some warning. A device that drew very little current might work well, however, since the drop would be small, but then a fault could occur to cause more current to flow, burning out the fault and leaving the case hot and the device seemingly off. Bad News! The current demand on a device would not determine an overload condition from a single fault unless it was grounded with a separate conductor. Burning out of the fault would disconnect the fault. Generally greatly overloaded windings will cause insulation failure and short circuit within the winding, draw excess current and more heating, also possibly causing a ground fault, eventually destroying continuity of the windings stopping its operation while still allowing that fault connection to an ungrounded device. I would welcome any corrections if I appear to be mistaken or misinformed. -- Chipper Wood useours, yours won't work "Wilson" wrote in message nk.net... Welll, let's look at this. I'm not addressing code, or what you should do, just the facts. Think electric drill with an insulation failure in the motor winding. For discussion, let's say the case is "connected" to the 120V hot wire. This device will work fine, but you'll be holding the 120V hot in your hand. Even that is fine, UNTIL you touch a "ground", like a water pipe or the case of a "grounded" appliance. At that point, YOU are a current carrying conductor and you will get a healthy (poor choice of word) ZAP. If you are really holding onto things, there is continuing current flow from arm to arm, about the worst way to get it, since it goes by your heart. NOW, there are some errors in some messages. The third wire "ground" is called that because it doesn't carry current. It is the same size as the others so it can carry enough current to trip the breaker involved when a fault occurs. It's there to suck up the fault current IF the neutral wire opens for some reason. BUT This is the government helping us by demanding a redundant ground path. Yes, there IS current in the neutral and yes, it can be above ground by a small amount (couple volts maybe) if high currents are flowing, BUT never enough to be harmful. Problems arise if the neutral is not well connected to ground at the box.. , but I HAVE seen a commercial electrician switch hot and ground, making a bunch of equipment cases 120V hot! Imagine the spark when I connected a signal cable from this equipment to something else that was plugged into an outlet that was properly wired! Thank heavens I didn't pick up the grounded device while holding the metal connector on the cable! At first thought, you might ask why not just connect neutral to the metal tool case and be done with it. That would work, AS LONG as the outlets and plugs were properly polarized (different width prongs) and connected. Unfortunately, old plugs were not polarized and newer ones can be miswired. Remember when "double insulated" tools were the rage? That was an intermediate stage of development during which two insulation systems were used. One was the regular motor insulation and the other was the plastic case of the tool. This is MUCH better than the two wire metal tool. Most cheap table radios with tubes had no transformer and could easily get their chassis hot to ground. In this case, the user was protected only by the case and knobs! If you followed the above, you can see the temptation to use the neutral as a ground. In fact, it would work fine and be safe, UNTIL you had a neutral wire fault, putting your device above ground and making it very dangerous! The GFI outlet is the right answer, unless you can pull new wire. It should be said here that a device needing considerable power plugged into an outlet with a serious neutral fault would not work properly, because of the voltage drop across the fault, so you might have some warning. A device that drew very little current might work well, however, since the drop would be small, but then a fault could occur to cause more current to flow, burning out the fault and leaving the case hot and the device seemingly off. Bad News! I'd try to get good hookups in kitchens and laundry areas, but your bedlamp and table radio don't have many dangers, partly because they are not near grounded metal, usually. Same for TVs, etc. A shop with a damp dirt floor needs protection, especially if you are barefooted. The hand to hand shock is the most likely and most dangerous. The hand to foot shock tends to be mitigated by non conductive shoes and dry floors. Shocks in your left arm are more dangerous than in your right, because of heart nerve location. Let me know if anything above is misstated or confusing. Wilson "John Moorhead" wrote in message . com... Folks - I have an old Victorian, Circa 1868.... The tenants trashed it, long story.... Anyway, most of the electric outlets are two prong, rather than grounded.... I would like to put grounded outlets in, but I have only a hot (black) and neutral (white) No separate ground wire.... Would it be safe to install a 3 wire plug and have the ground and neutral common to the white wire? Would this work and be safe? Only having 2 prong outlets has been a PITA, and getting under the house to run separate grounds would be a real bit of work. Would bridging the ground and common terminals also work and be safe with a GFCI outlet? I would appreciate any remarks from those that KNOW and have experience. The last thing I want is a fire.... I was under the house yesterday and found some old andirons.... All of the timber underneath is full dimension stuff, maybe even bigger.... Thanks in advance for any help that can be given.... John Moorhead |
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#36
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Semi OT Electrical Question
Wes Stewart writes:
On Thu, 8 Apr 2004 16:00:58 +0000 (UTC), wrote: [snip] | And of course, the local inspector |is the final authority. Unfortunately, so true. I added a laundry/sewing room and garage/workshop to my house. Because the laundry was a long way from the primary cooling system (dual evaporative/refrigerated), even though I tapped into the supply duct, I didn't expect much flow. Since I was also adding an evaporative cooler to the garage, I drew up plans that included a supplemental cooling duct from the garage into the laundry. To Oops. Instant fire code violation. There are reasons that the garage must (per NFPA codes) have: 1) 5/8" or thicker fire-rated drywall between garage and living areas. 2) Fire-rated, self-closing door(s) between living areas and garage and 3) No openings between garage and living areas, especially ductwork which can carry both fire and fumes from the garage into the living areas. scott |
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#38
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Semi OT Electrical Question
Look at the premise here. I said NEUTRAL FAULT to begin with. A small
device would work fine because it wouldn't be drawing enough current to cause serious drop across the neutral fault. If a serious fault then developed in the DEVICE, lots of current would flow, possibly burning open the neutral fault and leaving the device case hot. Maybe I should have separated the faults more clearly. Wilson "Chipper Wood" wrote in message ... For the sake of discussion, Most of this post is true. However there are some statements that I do not totally agree with in opinion. Danger arises when there is an electrical fault (leakage) from the hot wire or motor winding, etc., of a device to its metallic case. Any path for an electric potential to be transferred to a person be it metal, water or otherwise is a danger. , the neutral is the same size wire and connected to the ground at the panel. If it and its connections are good, it can do the same thing. Neutrals are current carrying conductors. A poor or open connection can induce up to the full potential voltage on it. Problems arise if the neutral is not well connected to ground at the box. Neutrals are bonded to ground at the service to insure incidental voltages induced in any circuit have a path to ground and not transferred to all the wiring. ( Lightning strikes to a service or other conductor as an example.) I've NEVER seen this happen in my 62 years. In my experience, overheated connection failures are about 80% in neutrals. Even on grounded device plugs. Never knew why.... BUT This is the government helping us by demanding a redundant ground path. The safety codes and rules are determined by tradesmen, fire officials, engineers and insurance companies. People directly involved. The government only tries to enforce them. Most cheap table radios with tubes had no transformer and could easily get their chassis hot to ground. In many this was done intentionally as one supply wire was deliberately connected to the 'isolated' chassis. It should be said here that a device needing considerable power plugged into an outlet with a serious neutral fault would not work properly, because of the voltage drop across the fault, so you might have some warning. A device that drew very little current might work well, however, since the drop would be small, but then a fault could occur to cause more current to flow, burning out the fault and leaving the case hot and the device seemingly off. Bad News! The current demand on a device would not determine an overload condition from a single fault unless it was grounded with a separate conductor. Burning out of the fault would disconnect the fault. Generally greatly overloaded windings will cause insulation failure and short circuit within the winding, draw excess current and more heating, also possibly causing a ground fault, eventually destroying continuity of the windings stopping its operation while still allowing that fault connection to an ungrounded device. I would welcome any corrections if I appear to be mistaken or misinformed. -- Chipper Wood useours, yours won't work "Wilson" wrote in message nk.net... Welll, let's look at this. I'm not addressing code, or what you should do, just the facts. Think electric drill with an insulation failure in the motor winding. For discussion, let's say the case is "connected" to the 120V hot wire. This device will work fine, but you'll be holding the 120V hot in your hand. Even that is fine, UNTIL you touch a "ground", like a water pipe or the case of a "grounded" appliance. At that point, YOU are a current carrying conductor and you will get a healthy (poor choice of word) ZAP. If you are really holding onto things, there is continuing current flow from arm to arm, about the worst way to get it, since it goes by your heart. NOW, there are some errors in some messages. The third wire "ground" is called that because it doesn't carry current. It is the same size as the others so it can carry enough current to trip the breaker involved when a fault occurs. It's there to suck up the fault current IF the neutral wire opens for some reason. BUT This is the government helping us by demanding a redundant ground path. Yes, there IS current in the neutral and yes, it can be above ground by a small amount (couple volts maybe) if high currents are flowing, BUT never enough to be harmful. Problems arise if the neutral is not well connected to ground at the box.. , but I HAVE seen a commercial electrician switch hot and ground, making a bunch of equipment cases 120V hot! Imagine the spark when I connected a signal cable from this equipment to something else that was plugged into an outlet that was properly wired! Thank heavens I didn't pick up the grounded device while holding the metal connector on the cable! At first thought, you might ask why not just connect neutral to the metal tool case and be done with it. That would work, AS LONG as the outlets and plugs were properly polarized (different width prongs) and connected. Unfortunately, old plugs were not polarized and newer ones can be miswired. Remember when "double insulated" tools were the rage? That was an intermediate stage of development during which two insulation systems were used. One was the regular motor insulation and the other was the plastic case of the tool. This is MUCH better than the two wire metal tool. Most cheap table radios with tubes had no transformer and could easily get their chassis hot to ground. In this case, the user was protected only by the case and knobs! If you followed the above, you can see the temptation to use the neutral as a ground. In fact, it would work fine and be safe, UNTIL you had a neutral wire fault, putting your device above ground and making it very dangerous! The GFI outlet is the right answer, unless you can pull new wire. It should be said here that a device needing considerable power plugged into an outlet with a serious neutral fault would not work properly, because of the voltage drop across the fault, so you might have some warning. A device that drew very little current might work well, however, since the drop would be small, but then a fault could occur to cause more current to flow, burning out the fault and leaving the case hot and the device seemingly off. Bad News! I'd try to get good hookups in kitchens and laundry areas, but your bedlamp and table radio don't have many dangers, partly because they are not near grounded metal, usually. Same for TVs, etc. A shop with a damp dirt floor needs protection, especially if you are barefooted. The hand to hand shock is the most likely and most dangerous. The hand to foot shock tends to be mitigated by non conductive shoes and dry floors. Shocks in your left arm are more dangerous than in your right, because of heart nerve location. Let me know if anything above is misstated or confusing. Wilson "John Moorhead" wrote in message . com... Folks - I have an old Victorian, Circa 1868.... The tenants trashed it, long story.... Anyway, most of the electric outlets are two prong, rather than grounded.... I would like to put grounded outlets in, but I have only a hot (black) and neutral (white) No separate ground wire.... Would it be safe to install a 3 wire plug and have the ground and neutral common to the white wire? Would this work and be safe? Only having 2 prong outlets has been a PITA, and getting under the house to run separate grounds would be a real bit of work. Would bridging the ground and common terminals also work and be safe with a GFCI outlet? I would appreciate any remarks from those that KNOW and have experience. The last thing I want is a fire.... I was under the house yesterday and found some old andirons.... All of the timber underneath is full dimension stuff, maybe even bigger.... Thanks in advance for any help that can be given.... John Moorhead |
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Semi OT Electrical Question
On Thu, 08 Apr 2004 20:50:32 GMT, (Scott Lurndal)
wrote: |Wes Stewart writes: |On Thu, 8 Apr 2004 16:00:58 +0000 (UTC), wrote: |[snip] | || And of course, the local inspector ||is the final authority. | | |Unfortunately, so true. | |I added a laundry/sewing room and garage/workshop to my house. |Because the laundry was a long way from the primary cooling system |(dual evaporative/refrigerated), even though I tapped into the supply |duct, I didn't expect much flow. Since I was also adding an |evaporative cooler to the garage, I drew up plans that included a |supplemental cooling duct from the garage into the laundry. To | |Oops. Instant fire code violation. There are reasons that the garage |must (per NFPA codes) have: | | 1) 5/8" or thicker fire-rated drywall between garage and | living areas. Done. 5/8 FC on the garage side, 3/4" (1/2 + 1/4) on the house side. | 2) Fire-rated, self-closing door(s) between living areas and garage and Done. | 3) No openings between garage and living areas, especially ductwork | which can carry both fire and fumes from the garage into the living | areas. Not quite what I was told. I should have added that the SOB inspector would have allowed thicker sheet metal ductwork and a fire operated damper on the laundry side. This was way too much hassle and expense for the limited use I would have made of it. My main bitch was that I wasted a coupla hundred bucks on sheetmetal and compromised the cooling in the shop by not optimally locating the cooler because of the screwed up inspection department. I should have just bribed them like the developers do and been done with it. Wes |
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Semi OT Electrical Question
Someone wrote:
| And of course, the local inspector |is the final authority. "Wes Stewart" added: Unfortunately, so true. snip a tale of inspection woes Your tale reminds me of my first supervisor, a brilliant engineer who designed and built his own home. The electrical distribution system was a marvel to observe. It included the early vintage low voltage control. When it was time for the electrical inspection before things could be finished, my supervisor took the day off and made arrangements to meet the electrical inspector to be on site to answer any questions he may have. A point of reference, at this point in time, unless it was knob and tube, a union electrician would not wire a house. This was not a knob and tube job since my supervisor did the work. This obviously raised a red flag, but so be it. As the story was related to me, my supervisor so totally overwhelmed the inspector with information that it was unnecessary to baffle him with bull****. (He had that way about him) After about 20 minutes, inspector signed off on the job. -- Lew S/A: Challenge, The Bullet Proof Boat, (Under Construction in the Southland) Visit: http://home.earthlink.net/~lewhodgett for Pictures |
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