I recently installed a service to a residential log cabin. Since the breaker box was 15 feet away from outside wall, I installed a 200 amp disconnect switch under the meter. From the disconnect, I installed 2-#4/0 and 1-#2/0 for the ground. The power company refused to hook up because they said that I needed to add and additional bonding conductor from the disconnect to the breaker box. Is this correct?
4th conductor for bonding
- Thread starter jlgii
- Start date
- Status
- Location
- Massachusetts
Re: 4th conductor for bonding
Yes.
Once you install your service disconnect, you must keep the neutral isolated from the grounding conductor.
So from the service disconnect to the panel indoors you need 4 wires
2 ungrounded Conductor
1 Grounded Conductor
1 Grounding Conductor
Yes.
Once you install your service disconnect, you must keep the neutral isolated from the grounding conductor.
So from the service disconnect to the panel indoors you need 4 wires
2 ungrounded Conductor
1 Grounded Conductor
1 Grounding Conductor
bphgravity
Senior Member
- Location
- Florida
Re: 4th conductor for bonding
Yes. Everything past the main service disconnect requires an EGC, including your main power feeder.
Yes. Everything past the main service disconnect requires an EGC, including your main power feeder.
jtester
Senior Member
- Location
- Las Cruces N.M.
Re: 4th conductor for bonding
while I might agree with the above two posts in this specific instance, 250.32(B)(2) recognizes that an equipment grounding conductor might not be run in feeders serving more than 1 building or structure, and when it isn't run, this paragraph tells you how to connect the grounding system. How do we reconcile running grounding conductors in all cases, with this section which clearly recognizes that they aren't? The utility guy in me says that there is no reason for a ground wire to a separate building, at least as a general rule.
Jim T
while I might agree with the above two posts in this specific instance, 250.32(B)(2) recognizes that an equipment grounding conductor might not be run in feeders serving more than 1 building or structure, and when it isn't run, this paragraph tells you how to connect the grounding system. How do we reconcile running grounding conductors in all cases, with this section which clearly recognizes that they aren't? The utility guy in me says that there is no reason for a ground wire to a separate building, at least as a general rule.
Jim T
charlie
Senior Member
- Location
- Indianapolis
Re: 4th conductor for bonding
Jim, you actually are looking at it backward. Assume just three wires in a 1? feeder from the home to the garage. If anything metal, gas pipe, water pipe, telephone with a ground, CATV cable with a shield, etc. is taken from the house to the garage now or in the future, he has a problem. Whatever metallic path that has been installed is now in parallel with the neutral and becomes a current carrying conductor.
The reality is that carrying the fourth wire is the rule and once in a while you can get by with three wires.
Jim, you actually are looking at it backward. Assume just three wires in a 1? feeder from the home to the garage. If anything metal, gas pipe, water pipe, telephone with a ground, CATV cable with a shield, etc. is taken from the house to the garage now or in the future, he has a problem. Whatever metallic path that has been installed is now in parallel with the neutral and becomes a current carrying conductor.
The reality is that carrying the fourth wire is the rule and once in a while you can get by with three wires.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: 4th conductor for bonding
jtester The code only allows a three wire feed to another building when there are no other parallel paths that can cause a problem when the neutral is used for bonding of the metal in this out building. when a service disconect is mounted on the same structure that also the panel is installed in there will be all kinds of parallel paths that could share the neutral current, which could be a shock hazard. This is why we must run 4 conductors after the main service disconect so none of the grounding in the building will have any neutral current on it that could be at a lower voltage than it would be found at the service grounding.
jtester The code only allows a three wire feed to another building when there are no other parallel paths that can cause a problem when the neutral is used for bonding of the metal in this out building. when a service disconect is mounted on the same structure that also the panel is installed in there will be all kinds of parallel paths that could share the neutral current, which could be a shock hazard. This is why we must run 4 conductors after the main service disconect so none of the grounding in the building will have any neutral current on it that could be at a lower voltage than it would be found at the service grounding.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: 4th conductor for bonding
I have to learn to type faster. LOL
I have to learn to type faster. LOL
charlie
Senior Member
- Location
- Indianapolis
Re: 4th conductor for bonding
Come on Wayne, shove it into overdrive.
Come on Wayne, shove it into overdrive.
jtester
Senior Member
- Location
- Las Cruces N.M.
Re: 4th conductor for bonding
wayne and charlie
I don't disagree with you guys, I just don't know where Code says we must.
I don't know if it is economics, technology, or what, but slowly, evidence to support my argument that "it's how utility systems operate" is fading away. Clearly though in the past, with metal water lines, gas lines, sewer lines, CATV sheaths, etc., utility systems operated this way for years.
Jim T.
wayne and charlie
I don't disagree with you guys, I just don't know where Code says we must.
I don't know if it is economics, technology, or what, but slowly, evidence to support my argument that "it's how utility systems operate" is fading away. Clearly though in the past, with metal water lines, gas lines, sewer lines, CATV sheaths, etc., utility systems operated this way for years.
Jim T.
- Location
- Illinois
- Occupation
- retired electrician
Re: 4th conductor for bonding
Jim,
I agree with you,about the need for the fourth wire, but the code is clear that we must provide in any case where there is aparallel path. The electrons behave the same way on both sides of the cash register, so why are the rules different on one side? Unless the electrons "smart" enough to know who owns them, the hazard, or lack there of, is the same on both sides of the meter? Bennie, also made the point the the fault clearing capacity at the second building is reduced when the fourth wire is used, because in most cases the EGC is smaller than the grounded conductor.
Don
Jim,
I agree with you,about the need for the fourth wire, but the code is clear that we must provide in any case where there is aparallel path. The electrons behave the same way on both sides of the cash register, so why are the rules different on one side? Unless the electrons "smart" enough to know who owns them, the hazard, or lack there of, is the same on both sides of the meter? Bennie, also made the point the the fault clearing capacity at the second building is reduced when the fourth wire is used, because in most cases the EGC is smaller than the grounded conductor.
Don
Re: 4th conductor for bonding
I recently started working with a new Electrical
And they use alot of ringless feedthrew meters.
My question is with bonding, they are feeding from the ringless feedthrew with a 200 amp main
breaker to the panelbox inside the house is this considered a subfed panel done like this if so does a four wire need to be run and the ground and neutral need to be isolated.
I recently started working with a new Electrical
And they use alot of ringless feedthrew meters.
My question is with bonding, they are feeding from the ringless feedthrew with a 200 amp main
breaker to the panelbox inside the house is this considered a subfed panel done like this if so does a four wire need to be run and the ground and neutral need to be isolated.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: 4th conductor for bonding
jtester
jtester
Look at 250.24(A)(5)
Then 250.32(B)(2) for the requirement of separate buildings or structures.:
And 250.142 for where the grounded service conductor is allowed to also ground equipment on the supply side of the service only:
Now you know.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: 4th conductor for bonding
Massey:
After the main service breaker "Yes"
Massey:
Before the main service breaker "No"
After the main service breaker "Yes"
jtester
Senior Member
- Location
- Las Cruces N.M.
Re: 4th conductor for bonding
hurk27
Thanks for the help. I read your post and 250.32(B) a couple of more times and finally see the light.
If I had 2 buildings on my property, and I fed the second from the first, I would run an EGC. If I asked for two services from the utility there would a common neutral between the two, with no separate EGC. Since I worked for utilities for many years, and did this with no concern for interconnecting metallic paths, I still wonder how it wasn't a problem. Or maybe should I change my name, or move to Brazil?
Jim T
hurk27
Thanks for the help. I read your post and 250.32(B) a couple of more times and finally see the light.
If I had 2 buildings on my property, and I fed the second from the first, I would run an EGC. If I asked for two services from the utility there would a common neutral between the two, with no separate EGC. Since I worked for utilities for many years, and did this with no concern for interconnecting metallic paths, I still wonder how it wasn't a problem. Or maybe should I change my name, or move to Brazil?
Jim T
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