|
Why must ground & neutral be seperate in subpanel?
I installed a subpanel when I switched from an electric stove to gas. I
used the 40A 220V breaker that formerly served the stove to power the sub panel. The cable is #4 with two conductors and a ground. I have 6- 15 amp breakers in the panel providing branch circuits for my kitchen and other areas of my house. The grounds and neutrals all share the common bus bar in the sub panel. Everything has worked fine for years now. Can someone explain why I read that ground and neutral are to be isolated in the sub panel? Please don't answer because of the NEC since that does not explain why. What is the risk of my current situation? Thanks, Joe |
Why must ground & neutral be seperate in subpanel?
|
Why must ground & neutral be seperate in subpanel?
|
Why must ground & neutral be seperate in subpanel?
What is the risk of my current situation?
For one thing, it puts current into the ground conductor between the subpanel and main panel. |
Why must ground & neutral be seperate in subpanel?
wrote in message ups.com... I installed a subpanel when I switched from an electric stove to gas. I used the 40A 220V breaker that formerly served the stove to power the sub panel. The cable is #4 with two conductors and a ground. I have 6- 15 amp breakers in the panel providing branch circuits for my kitchen and other areas of my house. The grounds and neutrals all share the common bus bar in the sub panel. Everything has worked fine for years now. Can someone explain why I read that ground and neutral are to be isolated in the sub panel? Please don't answer because of the NEC since that does not explain why. What is the risk of my current situation? Thanks, Joe The Reason is that there is current goes through a nuteral and no current goes through a ground and if the ground and nutural are tied together they both have current passing through them and the only time that current should go through a ground is when there is a short or something similar... but to make thing even moree confusing is then why is the nurural and ground tied together at the main pannel and that is to bond the nuural to the earth ground... |
Why must ground & neutral be seperate in subpanel?
wrote in message ups.com... I installed a subpanel when I switched from an electric stove to gas. I used the 40A 220V breaker that formerly served the stove to power the sub panel. The cable is #4 with two conductors and a ground. I have 6- 15 amp breakers in the panel providing branch circuits for my kitchen and other areas of my house. The grounds and neutrals all share the common bus bar in the sub panel. Everything has worked fine for years now. Can someone explain why I read that ground and neutral are to be isolated in the sub panel? Please don't answer because of the NEC since that does not explain why. What is the risk of my current situation? The neutral (white) is a return ... it carries the same current as the hot wire (black). The ground wire is a non current-carrying safety wire (often bare copper). The purpose of the ground wire is to reduce voltages in the case of lightning or an accident (wires falling across other wires outside of your home and raising the voltage with respect to ground to a dangerous level). The ground wire only conducts current in the case of a fault. Ground fault circuit interrupters need the ground wire to detect such faults and open the circuit when they occur. People are often shocked and even electrocuted with voltages with respect to ground ... one is standing on a wet basement floor ... one is touching a faucet ... one is in the tub or shower. The voltage with respect to ground is the big issue here (for safety reasons). An ungrounded electrical system in your home would allow voltages to rise to thousands of volts above ground and fry you if you happened to be grounded (in a tub or standing on a wet concrete floor). |
Why must ground & neutral be seperate in subpanel?
The Reason is that there is current goes through a nuteral and no current goes through a ground and if the ground and nutural are tied together they both have current passing through them and the only time that current should go through a ground is when there is a short or something similar... but to make thing even moree confusing is then why is the nurural and ground tied together at the main pannel and that is to bond the nuural to the earth ground... OK, so the ground is bonded to the neutral at the service panel. What about the transfromer at the pole? Is the neutral center-tap in the North American System bonded to the transformer enclosure? Is this point often connected to a ground wire running down the pole and into the earth? Also, why in the US systems is the top wire on the pole the hot wire (for the transformer primary) and the neutral is usually several feet below this? Is this arrangement not more prone to lightning damage? Beachcomber |
Why must ground & neutral be seperate in subpanel?
"Charles Schuler" wrote in message The neutral (white) is a return ... it carries the same current as the hot wire (black). The ground wire is a non current-carrying safety wire (often bare copper). The purpose of the ground wire is to reduce voltages in the case of lightning or an accident (wires falling across other wires outside of your home and raising the voltage with respect to ground to a dangerous level). The ground wire only conducts current in the case of a fault. Ground fault circuit interrupters need the ground wire to detect such faults and open the circuit when they occur. I believe that GFIs are often recommended in cases where there is no ground for safety. They do not need a ground AFAIN. Bob |
Why must ground & neutral be seperate in subpanel?
|
Why must ground & neutral be seperate in subpanel?
"Bob F" wrote in message ... "Charles Schuler" wrote in message The neutral (white) is a return ... it carries the same current as the hot wire (black). The ground wire is a non current-carrying safety wire (often bare copper). The purpose of the ground wire is to reduce voltages in the case of lightning or an accident (wires falling across other wires outside of your home and raising the voltage with respect to ground to a dangerous level). The ground wire only conducts current in the case of a fault. Ground fault circuit interrupters need the ground wire to detect such faults and open the circuit when they occur. I believe that GFIs are often recommended in cases where there is no ground for safety. They do not need a ground AFAIN. They need the ground wire. |
Why must ground & neutral be seperate in subpanel?
I believe that GFIs are often recommended in cases where there is no ground for safety. They do not need a ground AFAIN. They need the ground wire. When a ground is available at an outlet with a GFCI it is preferred (and required) that it be installed, However, where there is no ground the NEC still recognized that a GFCI can still provide protection by detecting an imbalance in currents between the neutral and hot wire. In this case, the user must be informed (with a small sticker on the outlet) that the GFCI is ungrounded. Beachcomber |
Why must ground & neutral be seperate in subpanel?
Charles Schuler wrote:
"Bob F" wrote in message I believe that GFIs are often recommended in cases where there is no ground for safety. They do not need a ground AFAIN. They need the ground wire. Actually, they don't. See section 210-7(d) in the NEC, and section 26-700(9) in the CEC. GFCIs are a legal substitute for a grounded outlet in an existing installation where there is no ground available in the outlet box. Chris |
Why must ground & neutral be seperate in subpanel?
All household grounds must meet only at a common point for reasons
similar to why ground loops create hum in a stereo system. Neutral, equipment ground, and earth ground that connect at a common point (main breaker box safety ground) avoids 'ground loops' and other adverse or surprise currents. To explain same using a different perspective, first, all wires are electrically different at both ends. That difference increases as more current flows. To better explain this, we express that difference as a separation or electrical distance. A three prong appliance is powered from wires that are distant from the breaker box (because they carry current). A separate safety (equipment) ground wire connects directly (shorter) to breaker box safety ground because it carries no current. Appliance connected electrically shorter to breaker box means greater human safety. Again, if safety ground and neutral wire were connected anywhere (other than in breaker box), then that safety ground wire would be electrically farther from breaker box (because it carries current). Another perspective that explains why NEC demands separate neutral and ground wires. Another situation: suppose neutral and safety ground wire were both carrying current. Suddenly that common wire breaks. What happens to appliance connected to third prong safety ground? It suddenly becomes electrically hot - directly connected to black hot wire. AND no safety ground exists to protect human and trip circuit breaker. We want neutral wire separated from safety ground so that any neutral wire break always leaves appliance still connected directly to breaker box safety ground and not connected to a neutral wire that is no longer connected to breaker box. Just another reason why those two wires always remain separate. Home has its own single point safety ground inside breaker box. Power wires connect that system to another system that has its own single point ground - pole transformer. Pole transformer connects primary (high voltage) ground, secondary neutral, and earth ground to a common point. Lightning strike to primary (high voltage) wire simply gets conducted safely to earth at transformer which is but one reason why that primary wire can be highest on pole. Meanwhile, household single point ground in breaker box is one ground system centered at a single point. Transformer has its own single point ground system. How far apart are those two grounds? As current increases on neutral wire (transformer to house), then both grounds become electrically more separated. Again, using a perspective of electrical distance to explain a concept. wrote: I installed a subpanel when I switched from an electric stove to gas. I used the 40A 220V breaker that formerly served the stove to power the sub panel. .... The grounds and neutrals all share the common bus bar in the sub panel. Everything has worked fine for years now. Can someone explain why I read that ground and neutral are to be isolated in the sub panel? Please don't answer because of the NEC since that does not explain why. What is the risk of my current situation? |
Why must ground & neutral be seperate in subpanel?
wrote in message
ups.com... I installed a subpanel when I switched from an electric stove to gas. I used the 40A 220V breaker that formerly served the stove to power the sub panel. The cable is #4 with two conductors and a ground. I have 6- 15 amp breakers in the panel providing branch circuits for my kitchen and other areas of my house. The grounds and neutrals all share the common bus bar in the sub panel. Everything has worked fine for years now. Can someone explain why I read that ground and neutral are to be isolated in the sub panel? Please don't answer because of the NEC since that does not explain why. What is the risk of my current situation? Thanks, Joe So, what is the proper way to connect a 220v sub-panel that has a single bus bar for neutral and ground to a main panel with the neutral bar bonded to the ground bar? |
Why must ground & neutral be seperate in subpanel?
On Mon, 27 Nov 2006 15:42:02 -0800, "Bob F"
wrote: "Charles Schuler" wrote in message The neutral (white) is a return ... it carries the same current as the hot wire (black). The ground wire is a non current-carrying safety wire (often bare copper). The purpose of the ground wire is to reduce voltages in the case of lightning or an accident (wires falling across other wires outside of your home and raising the voltage with respect to ground to a dangerous level). The ground wire only conducts current in the case of a fault. Ground fault circuit interrupters need the ground wire to detect such faults and open the circuit when they occur. I believe that GFIs are often recommended in cases where there is no ground for safety. They do not need a ground AFAIN. Bob A GFCI does not need a ground. Then some people get the strange idea that it PROVIDES one. It does not. -- 28 days until the winter solstice celebration Mark Lloyd http://notstupid.laughingsquid.com "Unlike biological evolution. 'intelligent design' is not a genuine scientific theory and, therefore, has no place in the curriculum of our nation's public school classes." -- Ted Kennedy |
Why must ground & neutral be seperate in subpanel?
In article , "The Streets" wrote:
So, what is the proper way to connect a 220v sub-panel that has a single bus bar for neutral and ground to a main panel with the neutral bar bonded to the ground bar? There isn't one. To make a Code-compliant connection, you must install a second bar so that you can separate the neutral and ground conductors for the various circuits to separate busses. The neutral bus must be electrically insulated from the ground bus and from the panel chassis, and the ground bus must *not* be insulated from the chassis. *Also* you must connect the subpanel to the main panel using *four* conductors, e.g. black, red, white, and bare (or green). White goes from the neutral bus bar in the main panel to the neutral bus bar in the subpanel. Bare (or green) goes from the ground bus bar in the main panel to the ground bus bar in the subpanel. Black and red go from the two lugs on the circuit breaker in the main panel which feeds the sub, to the lugs on the main breaker in the subpanel. -- Regards, Doug Miller (alphageek at milmac dot com) It's time to throw all their damned tea in the harbor again. |
Why must ground & neutral be seperate in subpanel?
Beachcomber wrote: What about the transfromer at the pole? Is the neutral center-tap in the North American System bonded to the transformer enclosure? Is this point often connected to a ground wire running down the pole and into the earth? Also, why in the US systems is the top wire on the pole the hot wire (for the transformer primary) and the neutral is usually several feet below this? Is this arrangement not more prone to lightning damage? That was the old way - keeping the hot wire as far from people/animals as possible. The vast majority of new installations will put the ground wire on top. But what about the rural Canadian systems where there is only a hot wire with no ground at all? Are they any more susceptable to lightning than a US hot top wire system? |
Why must ground & neutral be seperate in subpanel?
|
Why must ground & neutral be seperate in subpanel?
On Mon, 27 Nov 2006 21:52:35 -0500, krw wrote:
In article , says... On Mon, 27 Nov 2006 15:42:02 -0800, "Bob F" wrote: I believe that GFIs are often recommended in cases where there is no ground for safety. They do not need a ground AFAIN. Bob A GFCI does not need a ground. Then some people get the strange idea that it PROVIDES one. It does not. No one said GFCIs did. I said that because people have. Just not in THIS thread, but in this group. BobF said they are "recommended in cases where there is no ground". They are. What's your beef? I was saying that only because some people think they provide ground. -- 28 days until the winter solstice celebration Mark Lloyd http://notstupid.laughingsquid.com "Unlike biological evolution. 'intelligent design' is not a genuine scientific theory and, therefore, has no place in the curriculum of our nation's public school classes." -- Ted Kennedy |
Why must ground & neutral be seperate in subpanel?
Doug Miller wrote: In article , "The Streets" wrote: So, what is the proper way to connect a 220v sub-panel that has a single bus bar for neutral and ground to a main panel with the neutral bar bonded to the ground bar? There isn't one. To make a Code-compliant connection, you must install a second bar so that you can separate the neutral and ground conductors for the various circuits to separate busses. The neutral bus must be electrically insulated from the ground bus and from the panel chassis, and the ground bus must *not* be insulated from the chassis. *Also* you must connect the subpanel to the main panel using *four* conductors, e.g. black, red, white, and bare (or green). White goes from the neutral bus bar in the main panel to the neutral bus bar in the subpanel. Bare (or green) goes from the ground bus bar in the main panel to the ground bus bar in the subpanel. Black and red go from the two lugs on the circuit breaker in the main panel which feeds the sub, to the lugs on the main breaker in the subpanel. -- Regards, Doug Miller (alphageek at milmac dot com) It's time to throw all their damned tea in the harbor again. Thanks everyone, especially Doug for this post which spells it out clearly. Please comment on this proposed "fix": I run another wire back to the main panel (I'll probably use some 12/2 with ground) and attach all three conductors to the ground bar in the main panel. Then, at the sub panel, I will connect all grounds to the new cable but not to the neutral bus bar. Now all grounds will be grounded back at the main panel, and the neutral in the sub will be isolated from the grounds and from the sub panel chassis. (as long as I remove the grounding screw from the neutral bus bar) Thanks again for your responses. Joe |
Why must ground & neutral be seperate in subpanel?
|
Why must ground & neutral be seperate in subpanel?
Doug Miller wrote:
In article , "The Streets" wrote: So, what is the proper way to connect a 220v sub-panel that has a single bus bar for neutral and ground to a main panel with the neutral bar bonded to the ground bar? There isn't one. To make a Code-compliant connection, you must install a second bar so that you can separate the neutral and ground conductors for the various circuits to separate busses. The neutral bus must be electrically insulated from the ground bus and from the panel chassis, and the ground bus must *not* be insulated from the chassis. *Also* you must connect the subpanel to the main panel using *four* conductors, e.g. black, red, white, and bare (or green). White goes from the neutral bus bar in the main panel to the neutral bus bar in the subpanel. Bare (or green) goes from the ground bus bar in the main panel to the ground bus bar in the subpanel. Black and red go from the two lugs on the circuit breaker in the main panel which feeds the sub, to the lugs on the main breaker in the subpanel. This is great but it doesn't mention wire size. If the ground is smaller than the current-carrying conductors, doesn't it become a fire hazard? -tg -- Regards, Doug Miller (alphageek at milmac dot com) It's time to throw all their damned tea in the harbor again. |
Why must ground & neutral be seperate in subpanel?
12/2 wire to power a 40 amp breaker? Not acceptable. 12/2 when, as
Doug said, four wires are required? 12/2 is not four wires and not sufficient gauge. wrote: Thanks everyone, especially Doug for this post which spells it out clearly. Please comment on this proposed "fix": I run another wire back to the main panel (I'll probably use some 12/2 with ground) and attach all three conductors to the ground bar in the main panel. Then, at the sub panel, I will connect all grounds to the new cable but not to the neutral bus bar. Now all grounds will be grounded back at the main panel, and the neutral in the sub will be isolated from the grounds and from the sub panel chassis. (as long as I remove the grounding screw from the neutral bus bar) Thanks again for your responses. Joe |
Why must ground & neutral be seperate in subpanel?
|
Why must ground & neutral be seperate in subpanel?
In article .com, "w_tom" wrote:
12/2 wire to power a 40 amp breaker? Not acceptable. 12/2 when, as Doug said, four wires are required? 12/2 is not four wires and not sufficient gauge. He's talking about using that entire cable as the grounding conductor for the subpanel. Still not safe, still not Code-compliant... but not quite as bad an idea as you assumed. -- Regards, Doug Miller (alphageek at milmac dot com) It's time to throw all their damned tea in the harbor again. |
Why must ground & neutral be seperate in subpanel?
|
Why must ground & neutral be seperate in subpanel?
|
Why must ground & neutral be seperate in subpanel?
"Chris Friesen" wrote in message ... Charles Schuler wrote: "Bob F" wrote in message I believe that GFIs are often recommended in cases where there is no ground for safety. They do not need a ground AFAIN. They need the ground wire. Actually, they don't. I should have said "Not a good idea." http://members.tripod.com/~masterslic/FAQ-2/7.html Problems are they are supposed to labeled as "ungrounded" and external testers won't work. |
Why must ground & neutral be seperate in subpanel?
"Doug Miller" wrote in message t... In article . com, wrote: But the ground is meant to protect against a short to the 'case', so if a short happens, the ground will not be protected by the circuit breaker---it will overheat. The breaker will trip long before the wire will melt. Specifically, because it is a "short" condition, rather than an overload, which can last much longer. Bob |
Why must ground & neutral be seperate in subpanel?
On Tue, 28 Nov 2006 12:21:33 -0500, krw wrote:
In article , says... On Mon, 27 Nov 2006 21:52:35 -0500, krw wrote: In article , says... On Mon, 27 Nov 2006 15:42:02 -0800, "Bob F" wrote: I believe that GFIs are often recommended in cases where there is no ground for safety. They do not need a ground AFAIN. Bob A GFCI does not need a ground. Then some people get the strange idea that it PROVIDES one. It does not. No one said GFCIs did. I said that because people have. Just not in THIS thread, but in this group. Then perhaps you should correct those who are mistaken? BobF said they are "recommended in cases where there is no ground". They are. What's your beef? I was saying that only because some people think they provide ground. No one in this threadlet. A lot of people read these things without making their presence known. Some will make up the wrong thing. -- 27 days until the winter solstice celebration Mark Lloyd http://notstupid.laughingsquid.com "Unlike biological evolution. 'intelligent design' is not a genuine scientific theory and, therefore, has no place in the curriculum of our nation's public school classes." -- Ted Kennedy |
Why must ground & neutral be seperate in subpanel?
I believe that GFIs are often recommended in cases where there is no ground for safety. They do not need a ground AFAIN. Bob A GFCI does not need a ground. Then some people get the strange idea that it PROVIDES one. It does not. Will the TEST BUTTON on the GFI work if it does not have a ground? If so, how does it work? Mark |
Why must ground & neutral be seperate in subpanel?
Doug Miller wrote:
In article . com, wrote: But the ground is meant to protect against a short to the 'case', so if a short happens, the ground will not be protected by the circuit breaker---it will overheat. The breaker will trip long before the wire will melt. -- Regards, Doug Miller (alphageek at milmac dot com) It's time to throw all their damned tea in the harbor again. Again, Thanks for the input. To clarify what I should have written, my plan was to tie my new cable into a ground bussbar which will be secured to the metal of the subpanel. The current neutral bar either floats or is grounded depending on one screw which makes the ground connection. I will remove that to make it float. Regarding the guage and being seperate from the supply, well sometimes something is better than nothing. 3 #12 conductors all tied to the main panel ground bus and to the sub panel ground bus is better than the current situation. Each #12 conductor is good for 20 Amps, so in theory my ground wire(s) can carry 60A combined, and it is only a 40A breaker. A lesser evil than the current situation which has not been problematic so far anyway. When I shop for the bussbar I will price a length of #4 bare copper and consider running that to the main instead. The issue then will be finding a lug in the main large enough to bond it to. Regards, Joe |
Why must ground & neutral be seperate in subpanel?
In article . com, wrote:
Doug Miller wrote: In article . com, wrote: But the ground is meant to protect against a short to the 'case', so if a short happens, the ground will not be protected by the circuit breaker---it will overheat. The breaker will trip long before the wire will melt. Or, I should have noted, long before the wire will get hot enough to cause any kind of problem. Again, Thanks for the input. To clarify what I should have written, my plan was to tie my new cable into a ground bussbar which will be secured to the metal of the subpanel. That's better... but it's still a Code violation. All conductors for any circuit are required to be in the same conduit, cable, raceway, etc. Furthermore, Code also prohibits connecting conductors in parallel unless they're (I believe) 2ga or larger. The current neutral bar either floats or is grounded depending on one screw which makes the ground connection. I will remove that to make it float. Correct. Regarding the guage and being seperate from the supply, well sometimes something is better than nothing. 3 #12 conductors all tied to the main panel ground bus and to the sub panel ground bus is better than the current situation. Undoubtedly. But it's still a Code violation. If you're going to run a new cable anyway, why not run the right thing, connect it up properly, and be done with it? Each #12 conductor is good for 20 Amps, so in theory my ground wire(s) can carry 60A combined, Doesn't matter -- Code doesn't permit it. and it is only a 40A breaker. A lesser evil than the current situation which has not been problematic so far anyway. Understood -- but you asked for the proper way of doing this. What you propose is not. When I shop for the bussbar I will price a length of #4 bare copper and consider running that to the main instead. It's still a Code violation, because it's not in the same cable as the conductors supplying the subpanel. You need to replace the existing feed with 8-3 cable (given that you're using a 40A breaker) with ground, so that all of the conductors are in the same cable. And you won't have any trouble finding a lug in the main that you can connect #8 to. -- Regards, Doug Miller (alphageek at milmac dot com) It's time to throw all their damned tea in the harbor again. |
Why must ground & neutral be seperate in subpanel?
I think it was "Mark" who stated:
Will the TEST BUTTON on the GFI work if it does not have a ground? Yes. If so, how does it work? Very well[*] What it does is measure the current leaving the "hot" lead and compares it with the current returning in the "neutral" lead. If those are different by more than a few milliamperes, there is a Ground Fault, that is, current is finding its way to ground through some other path than "neutral". If that is the case, the GFCI Interrupts (the "I" part of "GFCI") the Circuit, very, very quickly, so that no damage is done to whatever caused the Fault (that could be a human body). The test button simulates a fault. [*] I had it work once for me. I didn't know it had until the lamp I had dropped into water wouldn't come on again. -Don -- "What do *you* care what other people think?" --Arline Feynman |
Why must ground & neutral be seperate in subpanel?
On Tue, 28 Nov 2006 17:35:56 -0600, Don Fearn
wrote: I think it was "Mark" who stated: Will the TEST BUTTON on the GFI work if it does not have a ground? Yes. If so, how does it work? Very well[*] What it does is measure the current leaving the "hot" lead and compares it with the current returning in the "neutral" lead. If those are different by more than a few milliamperes, there is a Ground Fault, that is, current is finding its way to ground through some other path than "neutral". If that is the case, the GFCI Interrupts (the "I" part of "GFCI") the Circuit, very, very quickly, so that no damage is done to whatever caused the Fault (that could be a human body). The test button simulates a fault. [*] I had it work once for me. I didn't know it had until the lamp I had dropped into water wouldn't come on again. -Don Right answer to the wrong question. The GFCI will work, but unless there's a capacitor or something in there that I don't know about, the test button won't. |
Why must ground & neutral be seperate in subpanel?
On 28 Nov 2006 14:04:29 -0800, "Mark" wrote:
I believe that GFIs are often recommended in cases where there is no ground for safety. They do not need a ground AFAIN. Bob A GFCI does not need a ground. Then some people get the strange idea that it PROVIDES one. It does not. Will the TEST BUTTON on the GFI work if it does not have a ground? Yes. If so, how does it work? The one I examined connects a resistor between neutral on the line side and hot on the load side. Ground is not involved. Mark -- 27 days until the winter solstice celebration Mark Lloyd http://notstupid.laughingsquid.com "Unlike biological evolution. 'intelligent design' is not a genuine scientific theory and, therefore, has no place in the curriculum of our nation's public school classes." -- Ted Kennedy |
Why must ground & neutral be seperate in subpanel?
On Tue, 28 Nov 2006 18:50:22 -0500, Goedjn wrote:
On Tue, 28 Nov 2006 17:35:56 -0600, Don Fearn wrote: I think it was "Mark" who stated: Will the TEST BUTTON on the GFI work if it does not have a ground? Yes. If so, how does it work? Very well[*] What it does is measure the current leaving the "hot" lead and compares it with the current returning in the "neutral" lead. If those are different by more than a few milliamperes, there is a Ground Fault, that is, current is finding its way to ground through some other path than "neutral". If that is the case, the GFCI Interrupts (the "I" part of "GFCI") the Circuit, very, very quickly, so that no damage is done to whatever caused the Fault (that could be a human body). The test button simulates a fault. [*] I had it work once for me. I didn't know it had until the lamp I had dropped into water wouldn't come on again. -Don Right answer to the wrong question. The GFCI will work, but unless there's a capacitor or something in there that I don't know about, the test button won't. Yes, it will. The test button has nothing to do with ground. It creates an imbalance by routing some current from the hot side of the outlet around the GFCI to the neutral wire connected to it. This is the same sort of imbalance caused by a wet person touching hot. -- 27 days until the winter solstice celebration Mark Lloyd http://notstupid.laughingsquid.com "Unlike biological evolution. 'intelligent design' is not a genuine scientific theory and, therefore, has no place in the curriculum of our nation's public school classes." -- Ted Kennedy |
Why must ground & neutral be seperate in subpanel?
I think it was Goedjn who stated:
On Tue, 28 Nov 2006 17:35:56 -0600, Don Fearn wrote: I think it was "Mark" who stated: Will the TEST BUTTON on the GFI work if it does not have a ground? Yes. If so, how does it work? Very well[*] What it does is measure the current leaving the "hot" lead and compares it with the current returning in the "neutral" lead. If those are different by more than a few milliamperes, there is a Ground Fault, that is, current is finding its way to ground through some other path than "neutral". If that is the case, the GFCI Interrupts (the "I" part of "GFCI") the Circuit, very, very quickly, so that no damage is done to whatever caused the Fault (that could be a human body). The test button simulates a fault. [*] I had it work once for me. I didn't know it had until the lamp I had dropped into water wouldn't come on again. -Don Right answer to the wrong question. The GFCI will work, but unless there's a capacitor or something in there that I don't know about, the test button won't. A resistor, I believe. It shunts a small amount of current around the balance circuit simulating an imbalance in the two sides, so if it's working right the GFCI will interrupt the current. -D -- "What do *you* care what other people think?" --Arline Feynman |
Why must ground & neutral be seperate in subpanel?
Will the TEST BUTTON on the GFI work if it does not have a ground? Yes. If so, how does it work? The one I examined connects a resistor between neutral on the line side and hot on the load side. Ground is not involved. OK that makes sense, and the test will work without a ground and without a load... thanks Mark |
All times are GMT +1. The time now is 11:44 PM. |
|
Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004 - 2014 DIYbanter