n/a15

Sorry to have created a confusing question. Lets try it again. Forget all that I have said before. I saw a 200 amp main panel in a garage. There was no other disconnecting device between it and the meter. This panel had 4/0 Alminum service conductors wired into the service main breaker and neutral buss connection. The neutral busses were isolated from the panel box. There were two ground busses, one on each side of the panel box, bonded directly to the panel box. (This is to say they were isolated from the neutral busses and neutral service conductor.) A #4 bare copper grounding conductor was connected to the left side ground buss. All the house circuit ground wires are also connected to this ground buss. The right side ground buss is connected to the left side ground buss by the conductivity of the main panel box. Now this is what appears to be incorrect!!! The neutral wires from the house 110 & 220 V circuits are connected to the right side ground buss. They are not connected to either of the two neutral busses. Nothing is connected to the neutral busses except the main service conductor neutral. It would appear the all overcurrent traveling on the house neutrals would go to the ground buss and would only energize house circuit grounds with the electricity that cannot fit on the #4 copper main panel grounding conductor. I don't have a good enough overview of real time normal current loads and load balances to have a feel for the potential risk here. Jim Katen reports that "regrounding the neutral beyond the main service has been prohibited by the NEC since 1923" so I guess that may be what has happened here, then again it has happened in the main panel so is it really beyond the main service? In answer to Brian, yes if the main panel ground conductor system failed the service neutral would not be there to be a ground or neutral path and every grounded appliance cabinet would be looking for somebody to provide 'ground'! My question was what risk does this configuration create without any part of it failing or loosing connectivity? Mark Bishton Bloomfield, Indiana

Hello guys, Thanks for clarifying forum etiquette for me. I have modified my profile but will fess up on this note as well. My apologies but I don’t know you guys good enough to show you my girlfriends picture yet! I'm Mark Bishton. I have a one man inspection shop in Southern Indiana called Benchmark Home Services. I've worked in the home building business for over 30 years. Started as a grunt on a framing crew in 1970. Became sole proprietor of a small projects construction company in '78; incorporated in '82 and started building turnkey custom homes. I have been designing homes since '88. I joined ASHI in '96, then stopped building and started inspecting in 1998. Now that you know way more about me than you probably wanted, I'd like to get my question cleared up and answered. Funny how 53 years of trying to speak good English doesn't always get the job done! Can’t ever slack up! I tried to clearly describe this panel but should have also said, that there was no bonding screw, strap, etc. I should always be wary about using the word ‘correctly’; I guess that I tired of describing. So.... the bottom line of my question is this: When the neutral wires of various appliances and house circuits are connected to ground and not neutral what is the hazard? Is it a shock hazard or a fire hazard or an equipment hazard or is it just like me 'different'? Mark

I saw a 200 amp main service panel in an attached garage today. There was no exterior disconnect. The panel had neutral busses on each side and ground busses on each side. (Like a subpanel would need) The ground busses were isolated from the neutral and the service conductors, including the main grounding conductor were all in correctly. So far so good. All of the house circuit's ground conductors were connected to the left grounding buss and all the neutrals were connected to the right side grounding buss. The neutrals from the house were isolated from the main service neutral. I reported to my client that I did not believe this was proper and that the house circuit neutrals should have been connected to the neutral buss/es, and that it should be fully evaluated by a qualified electrician and corrected as necessary. I am not an electrician and would like to have a better overview on this. What are the possible hazards if these neutrals are grounded but isolated from the service neutral like this?

I thought that the actually diameter of a copper wire can vary within a given guage if the insulating capacity of the insulation wrap is greater or lesser. Wouldn't you need several labeled samples of say 12 guage wire and then wouldn't you also have to be able to read the labeling on the wire that you were comparing?