3 wire or 4 wire?

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guss

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I recently looked at a job with this situation.The house has a 100 amp main breaker panel on it.The panel is being fed by a 3 wire over head line that goes to a customer owned pole with a meter on it. The meter feeds a small outdoor panel with a 100 amp cb feeding the 3 wire over head line.My interpretation of the code is that,because the first point of disconnect is bonded ,the over head line should be a 4 wire line and neutrals and grounds seperated at the panel on the house.Thanks for any input.Please provide code referances.
Guss
 
It sounds like what I call a "farm load" center where one service drop connects to a single meter then serves multiple buildings from the customer side. Would you not be able to supply each structure with thre-wire as long as you re-establish the grouinding method at each structure. 4-wire would be required if you are passing through the same building, but maybe not in the case described by the original post. Any comments? Am I correct in thinking this way is acceptable?
 
Agreed with the above. Not legal under 2008 code, quite probably legal under earlier code. The pole and the home are separate structures.

-Jon
 
I agree with the agreement stated in the above post agreeing with the sentiment expressed in the previous post:smile:

It's Friday and I'm in love!!!
 
inspector 102 said:
It sounds like what I call a "farm load" center where one service drop connects to a single meter then serves multiple buildings from the customer side. Would you not be able to supply each structure with thre-wire as long as you re-establish the grouinding method at each structure. 4-wire would be required if you are passing through the same building, but maybe not in the case described by the original post. Any comments? Am I correct in thinking this way is acceptable?
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If we're talking '08NEC, then NO. . You would not be able/allowed to supply each structure with 3wires and no equipment ground even tho you be required to re-establish the grounding method at each structure [250.32(B)]. . If you want to run one hot, one neutral, + one equipment ground, that kind of 3wire would be fine. . Two hots, one neutral, + no equipment ground is no good.

You bring up a term that you refer to as "farm load". . If you're talking about an agricultural site-isolating device, the lack of an equipment ground would still be an issue. . 547.9(B)(3)(2) requires an equipment ground to be run from the site-isolating device distribution point to each building/structure. . You are allowed to place an OCPD at the distribution point if it's accessible [240.24(A)] and the site isolating does double duty as a service disconnect [547.9(C)]. . But either way you need an equipment ground from structure to structure.
 
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