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#1
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2 prong to 3 prong outlet conversion?
We just bought a new house and want to upgrade the electrical system,
some of which was done in the 60's when the house was built. The vast majority of the electrical outlets have only 2 wires, the ground terminal is missing. Some of the outlets are in the basement, where the wiring is partially accessible however. Is it legal (according to the electrical code) for me to change the outlet to a more modern 3 prong type and to obtain a ground from a nearby copper pipe or from one of the nearby plugs that already have a 3 prong outlet???? I notice the previous owner did this in several locations, but I need to know if it's legal to obtain a ground in this manner??? We live in Maine, but belive the National Code is the one that has jurisdiction. Thanks, A |
#2
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2 prong to 3 prong outlet conversion?
Ari wrote: We just bought a new house and want to upgrade the electrical system, some of which was done in the 60's when the house was built. The vast majority of the electrical outlets have only 2 wires, the ground terminal is missing. Some of the outlets are in the basement, where the wiring is partially accessible however. Is it legal (according to the electrical code) for me to change the outlet to a more modern 3 prong type and to obtain a ground from a nearby copper pipe or from one of the nearby plugs that already have a 3 prong outlet???? I notice the previous owner did this in several locations, but I need to know if it's legal to obtain a ground in this manner??? We live in Maine, but belive the National Code is the one that has jurisdiction. Thanks, A Might not be necessary; if the wiring is vintage 60s, it's most likely grounded via conduit or via BX cable. No? |
#3
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2 prong to 3 prong outlet conversion?
On Mon, 10 Jul 2006 15:39:42 -0400, Ari wrote:
We just bought a new house and want to upgrade the electrical system, some of which was done in the 60's when the house was built. The vast majority of the electrical outlets have only 2 wires, the ground terminal is missing. Some of the outlets are in the basement, where the wiring is partially accessible however. Is it legal (according to the electrical code) for me to change the outlet to a more modern 3 prong type and to obtain a ground from a nearby copper pipe or from one of the nearby plugs that already have a 3 prong outlet???? I notice the previous owner did this in several locations, but I need to know if it's legal to obtain a ground in this manner??? We live in Maine, but belive the National Code is the one that has jurisdiction. You should not use the plumbing system as the path-to-ground for your outlets, no. The simple "solution" is to replace the receptacles with GFCI outlets, and mark them "no equipment ground", (which labels ought to come with the recepticles). This will get you within shouting distance of the same level of protection. The complex solution is to run completely new wire. An intermediate solution is to pull a separate ground wire, and run it back to your service panel. If you do that, you want to make sure that no ground wire serves the devices on more than on circut, and that each one is big enough to handle the circut it's on. |
#4
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2 prong to 3 prong outlet conversion?
Might not be necessary; if the wiring is vintage 60s, it's most likely grounded via conduit or via BX cable. No? No, there are no ground wires in any on the junction boxes or in the outlet boxes. I've pulled apart a bunch of them to make sure. The cable is 2 conductor, no ground, no metal conduit. It just looks like Romex, except there is no third wire in it. The boxes are all metal and have the grounding screw, but of course, there is no third wire to attach to the grounding screw. So, the boxes are 'floating'. Can I run a large gauge single ground wire back to the box, and then attach individual ground wires from each outlet to the 'bus' wire? There is a very large copper wire already going to ground on the city water meter, can I attach other wires to this large ground wire since it goes to a true ground? Does the 'ground' truely have to go to the ground in the panel? Shouldn't any dedicated ground source be just as goodas the panel ground (such as a ground rod driven in hte ground)? I understand the gfi outlet solution (labeling each outlet to indicate there is no ground). I even understand WHY this is OK (because the GFI outlet senses current in both the neutral and the hot wire, and immediately trips if there is a difference between the current in each wire). But, I'd much rather have a real ground, if possible. A bus (or is it buss) solution is not ok? Thanks, A |
#5
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2 prong to 3 prong outlet conversion?
Ari wrote:
There is a very large copper wire already going to ground on the city water meter, can I attach other wires to this large ground wire since it goes to a true ground? Yes you can. That is a "grounding electrode conductor", and it is connected to the panel ground. Get a big copper split-bolt connector and use it to fasten your new grounding wires to that big wire.. Does the 'ground' truely have to go to the ground in the panel? Shouldn't any dedicated ground source be just as goodas the panel ground (such as a ground rod driven in hte ground)? It has to be electrically equivalent to the panel ground, not "just as good". IIRC, the panel itself, a grounding electrode conductor (big wire connecting the panel to a ground electrode), and the metal service raceway (conduit feeding the main panel, assuming it's metal conduit) are all OK places to connect your equipment grounding wires. A long time ago, it was permissible to use the nearest cold water pipe to make a ground, but no longer (someone might replace part of it with plastic pipe. Also, the plumber could get electrocuted when he cuts the metal pipe if there is current flowing thru it due to a fault.) Best regards, Bob |
#6
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2 prong to 3 prong outlet conversion?
Ari wrote: There is a very large copper wire already going to ground on the city water meter, can I attach other wires to this large ground wire since it goes to a true ground? Yes you can. That is a "grounding electrode conductor", and it is connected to the panel ground. Get a big copper split-bolt connector and use it to fasten your new grounding wires to that big wire.. Thanks Bob! Any caveats to using the big bus wire as a ground? For instance, the wire is copper, multi-stranded and appears to be 1/4 inch in diameter, or slightly larger. Do I have to worry about the current carrying capacity of that large gauge wire if it is hooked up to many outlets??? For instance, if the large bus wire is capable of carrying 100 amps, do I need to insure that no more than 5 20 amp outlets are grounded through that wire??? I did find 2 of the recently upgraded GFI outlets that were grounded to the copper plumbing and thought I'd better ask on here! Such a shame, the large copper grounding wire that runs to the water meter ground is right next to the copper plumbing lines! It would have been so easy to connect those grounds to the copper wire!!!! I have no idea why the previous owner used the copper plumbing with the large cooper ground wire running so close. Does the 'ground' truely have to go to the ground in the panel? Shouldn't any dedicated ground source be just as goodas the panel ground (such as a ground rod driven in hte ground)? It has to be electrically equivalent to the panel ground, not "just as good". IIRC, the panel itself, a grounding electrode conductor (big wire connecting the panel to a ground electrode), and the metal service raceway (conduit feeding the main panel, assuming it's metal conduit) are all OK places to connect your equipment grounding wires. OK, now that you mention it, there is some nearby wiring that was part of an addition they did just before deciding to sell the house. The new wiring is all metal conduit protected. Is the metal conduit of the newer wiring ok to use as a ground for the nearby legacy outlets? Or, do I have to run a ground wire inside a junction box and connect my ground wire to the existing ground in the conduit junction box? Thanks so much for the info. Regards A |
#7
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2 prong to 3 prong outlet conversion?
Ari wrote:
Ari wrote: There is a very large copper wire already going to ground on the city water meter, can I attach other wires to this large ground wire since it goes to a true ground? Yes you can. That is a "grounding electrode conductor", and it is connected to the panel ground. Get a big copper split-bolt connector and use it to fasten your new grounding wires to that big wire.. Thanks Bob! Any caveats to using the big bus wire as a ground? For instance, the wire is copper, multi-stranded and appears to be 1/4 inch in diameter, or slightly larger. Do I have to worry about the current carrying capacity of that large gauge wire if it is hooked up to many outlets??? For instance, if the large bus wire is capable of carrying 100 amps, do I need to insure that no more than 5 20 amp outlets are grounded through that wire??? No, you don't care about the current capacity of that wire. I did find 2 of the recently upgraded GFI outlets that were grounded to the copper plumbing and thought I'd better ask on here! Such a shame, the large copper grounding wire that runs to the water meter ground is right next to the copper plumbing lines! It would have been so easy to connect those grounds to the copper wire!!!! I have no idea why the previous owner used the copper plumbing with the large cooper ground wire running so close. That was common practice 30 years ago. (I'm guessing about the "30" part, but it's good guess, and a ballpark figure anyway.) Does the 'ground' truely have to go to the ground in the panel? Shouldn't any dedicated ground source be just as goodas the panel ground (such as a ground rod driven in hte ground)? It has to be electrically equivalent to the panel ground, not "just as good". IIRC, the panel itself, a grounding electrode conductor (big wire connecting the panel to a ground electrode), and the metal service raceway (conduit feeding the main panel, assuming it's metal conduit) are all OK places to connect your equipment grounding wires. OK, now that you mention it, there is some nearby wiring that was part of an addition they did just before deciding to sell the house. The new wiring is all metal conduit protected. Is the metal conduit of the newer wiring ok to use as a ground for the nearby legacy outlets? Or, do I have to run a ground wire inside a junction box and connect my ground wire to the existing ground in the conduit junction box? No. The metal conduit is probably a good enough ground for the circuits that run in it (or it might not if it wasn't installed well.) It's not good enough for grounding additional circuits. BTW, you don't really have to ground *everything*. I live in a 60 year-old house where all the basement wiring is grounded and none of the upstairs is grounded. I've been adding grounds over the years when I need one or when it's convenient because of another repair that I'm doing. I'm trying to get one or two properly-grounded outlets in each room. Think about it; do you really need a ground when you plug in your clock radio or a lamp? Of course not. But you want someplace to plug in your grounded vacuum cleaner (etc.) occasionally. Bob |
#8
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2 prong to 3 prong outlet conversion?
Good idea to GFI protect the basement outlets, except any for a
freezer/refrigerator. "Ari" wrote in message ... We just bought a new house and want to upgrade the electrical system, some of which was done in the 60's when the house was built. The vast majority of the electrical outlets have only 2 wires, the ground terminal is missing. Some of the outlets are in the basement, where the wiring is partially accessible however. Is it legal (according to the electrical code) for me to change the outlet to a more modern 3 prong type and to obtain a ground from a nearby copper pipe or from one of the nearby plugs that already have a 3 prong outlet???? I notice the previous owner did this in several locations, but I need to know if it's legal to obtain a ground in this manner??? We live in Maine, but belive the National Code is the one that has jurisdiction. Thanks, A |
#9
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2 prong to 3 prong outlet conversion?
Is it legal (according to the electrical code) for me to change the outlet to a more modern 3 prong type and to obtain a ground from a nearby copper pipe or from one of the nearby plugs that already have a 3 prong outlet???? I notice the previous owner did this in several locations, but I need to know if it's legal to obtain a ground in this manner??? We live in Maine, but belive the National Code is the one that has jurisdiction. If you are planning to pull a ground wire back to the panel, you might as well just plan on rewiring the outlets properly and legally with new grounded cable. Any separate ground that you run is going to be a kluge install and most likely would not pass code with an honest and knowlegable electrical inspector. Not being code compliant can affect your liability and fire insurance coverage. As another poster says, if you don't want to go to all that trouble and expense, putting in the GFCI's with the appropriate labels would be the easy (and perfectly legal) way to go. Beachcomber |
#10
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2 prong to 3 prong outlet conversion?
Beachcomber wrote:
Is it legal (according to the electrical code) for me to change the outlet to a more modern 3 prong type and to obtain a ground from a nearby copper pipe or from one of the nearby plugs that already have a 3 prong outlet???? I notice the previous owner did this in several locations, but I need to know if it's legal to obtain a ground in this manner??? We live in Maine, but belive the National Code is the one that has jurisdiction. If you are planning to pull a ground wire back to the panel, you might as well just plan on rewiring the outlets properly and legally with new grounded cable. Any separate ground that you run is going to be a kluge install and most likely would not pass code with an honest and knowlegable electrical inspector. Not being code compliant can affect your liability and fire insurance coverage. I haven't checked the most recent revision of the code to make sure it's still there, but the code specifically allows you to run a separate ground wire when upgrading old work. Think about it; the old ungrounded wiring is code compliant because there was no grounded requirement when it was installed. Adding a supplemental grounding wire can only make it safer (assuming the grounding wire goes back to the panel or grounding electrode system so a fault can't energize another circuit.) Bob |
#11
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2 prong to 3 prong outlet conversion?
Replace ALL the wires and be done with it......
On Mon, 10 Jul 2006 17:09:17 -0400, Ari wrote: Might not be necessary; if the wiring is vintage 60s, it's most likely grounded via conduit or via BX cable. No? No, there are no ground wires in any on the junction boxes or in the outlet boxes. I've pulled apart a bunch of them to make sure. The cable is 2 conductor, no ground, no metal conduit. It just looks like Romex, except there is no third wire in it. The boxes are all metal and have the grounding screw, but of course, there is no third wire to attach to the grounding screw. So, the boxes are 'floating'. Can I run a large gauge single ground wire back to the box, and then attach individual ground wires from each outlet to the 'bus' wire? There is a very large copper wire already going to ground on the city water meter, can I attach other wires to this large ground wire since it goes to a true ground? Does the 'ground' truely have to go to the ground in the panel? Shouldn't any dedicated ground source be just as goodas the panel ground (such as a ground rod driven in hte ground)? I understand the gfi outlet solution (labeling each outlet to indicate there is no ground). I even understand WHY this is OK (because the GFI outlet senses current in both the neutral and the hot wire, and immediately trips if there is a difference between the current in each wire). But, I'd much rather have a real ground, if possible. A bus (or is it buss) solution is not ok? Thanks, A |
#12
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2 prong to 3 prong outlet conversion?
On Tue, 11 Jul 2006 04:06:02 GMT, "peter" wrote:
An intermediate solution is to pull a separate ground wire, and run it back to your service panel. If you do that, you want to make sure that no ground wire serves the devices on more than on circut, and that each one is big enough to handle the circut it's on. So to serve more than one circuit, you need to pull more than one ground wire? Wouldn't it work just as well to pull a thicker ground wire? Probably. Esp. if you use 10 AWG wire. I mean, how likely are you the get three simultaneous high-resistance shorts from the same leg of your panel? But I know that the the former works, is safe, and is legal, and I don't know any of that for sure about the latter. |
#13
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2 prong to 3 prong outlet conversion?
Goedjn wrote:
On Tue, 11 Jul 2006 04:06:02 GMT, "peter" wrote: An intermediate solution is to pull a separate ground wire, and run it back to your service panel. If you do that, you want to make sure that no ground wire serves the devices on more than on circut, and that each one is big enough to handle the circut it's on. So to serve more than one circuit, you need to pull more than one ground wire? Wouldn't it work just as well to pull a thicker ground wire? Probably. Esp. if you use 10 AWG wire. I mean, how likely are you the get three simultaneous high-resistance shorts from the same leg of your panel? But I know that the the former works, is safe, and is legal, and I don't know any of that for sure about the latter. Equipment Grounding Conductors (EGCs) are sized for the size of the largest Over Current Protective Device supplying the conductors in a given box or other enclosure. As an extreme example lets use a junction box for the kitchen and laundry circuits in an apartment. If the box contains a fifty ampere stove circuit, a thirty ampere dryer circuit, a twenty ampere laundry circuit, a twenty ampere multiwire kitchen counter top circuits, a fifteen ampere multi wire dishwasher and disposal circuit, and a fifteen ampere multiwire refrigerator and microwave oven circuit it still only needs one equipment grounding conductor. That EGC is sized for the fifty ampere breaker for the stove. The only reason that the US NEC would require you to increase the size of the EGC is if you increased the size of the current carrying conductors to compensate for voltage drop. It just is not likely that there will be simultaneous faults on two or more of the circuits that EGC was installed to protect. -- Tom Horne Well we aren't no thin blue heroes and yet we aren't no blackguards to. We're just working men and woman most remarkable like you. |
#14
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2 prong to 3 prong outlet conversion?
On Tue, 11 Jul 2006 03:57:40 GMT, AZ Nomad
wrote: On Mon, 10 Jul 2006 20:53:02 -0500, zxcvbob wrote: I haven't checked the most recent revision of the code to make sure it's still there, but the code specifically allows you to run a separate ground wire when upgrading old work. Think about it; the old ungrounded wiring is code compliant because there was no grounded requirement when it was installed. Adding a supplemental grounding wire can only make it safer (assuming the grounding wire goes back to the panel or grounding electrode system so a fault can't energize another circuit.) Anything you touch is going to have to meet current code and the old wiring probably won't if it's sixty years old. If you're going to pull a ground through your walls, pulling new wiring isn't much more trouble. Thank you all for commenting, I appreciate all the info! I went down in the basement and pulled the cover off the entrance panel. The inspection I did was very interesting, especially in light of all the comments I've received to this post. The large (existing) ground wire that goes to the ground rod near the water main entrance IS the system ground for the electrical panel!!!!! Although the panel is on one end of the house and the water main is on the opposite end, it appears the original installer ran 50 feet of large gauge copper across the middle of the basement in order to ground the electrical service entrance panel. So, that big ole copper wire that is very accessible should make a fine ground! Regarding the comments by some that I should just rip out the old 2 conductor wire and install 3 conductor wire in it's place..... do keep in mind that the basement is finished, and gaining access to all the wires that feed the house would require a major demolition and restoration after the new wires were run. Not very practical:: However, adding a ground wire is much more practical because the added ground wire doesn't have to follow the path of the original 2 conductor wiring. Again, thanks to all who commented, I'll post an update here later on. Regards, A |
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