Originally Posted By: mpettitt This post was automatically imported from our archived forum.
Just need to double check myself.
New sub-panel in detached garage, three wire feed, separate ground rod, 2 hots and a neutral, neutrals and grounds are bonded, is this correct. I hope someone can reply soon as report has to be out.
Originally Posted By: Greg Fretwell This post was automatically imported from our archived forum.
250.32(B)(2) Grounded Conductor. Where (1) an equipment grounding conductor is not run with the supply to the building or structure, (2) there are no continuous metallic paths bonded to the grounding system in both buildings or structures involved, and (3) ground-fault protection of equipment has not been installed on the common ac service, the grounded circuit conductor run with the supply to the building or structure shall be connected to the building or structure disconnecting means and to the grounding electrode(s) and shall be used for grounding or bonding of equipment, structures, or frames required to be grounded or bonded. The size of the grounded conductor shall not be smaller than the larger of
Originally Posted By: mpettitt This post was automatically imported from our archived forum.
Mike and Greg, thanks for your quick replies, but if I’m not mistaken you both gave two different answers. I, too always thought that neutrals and grounds should be separated at a sub-panel, but after viewing several other posts on the subject, I am now not sure. What you said Greg is pretty much what I’ve read lately which prompted me to post this message. So, if I’m reading you correctly (Greg) it is okay for the neutrals and grounds to be bonded. Right?
Originally Posted By: jtedesco This post was automatically imported from our archived forum.
mpettitt wrote:
Just need to double check myself.
New sub-panel in detached garage, three wire feed, separate ground rod, 2 hots and a neutral, neutrals and grounds are bonded, is this correct. I hope someone can reply soon as report has to be out.
Question: You say "three wire feed." What type of wiring method is being used? Is it a cable assembly, or is it a conduit or tubing and is it metal or nonmetallic?
The quick and immediate answers here are always admirable, and give references that may be accurate according to the most recent edition of the NEC.
Pictures are necessary when these types of questions are asked, just trying to save you from being embarrassed or held liable for making a mistake!
Originally Posted By: pdickerson This post was automatically imported from our archived forum.
Mike,
Make sure that there is no conductive path between the two buildings. Water pipes, chain link fences, and concrete sidewalks might provide a path for return current through the grounding system.
Originally Posted By: mpettitt This post was automatically imported from our archived forum.
Joe, you are absolutely right, I should have mentioned that it was plastic conduit. I have to admit that I’ve been struggling with this issue concerning when it is okay for the neutrals and grounds to be bonded in a sub-panel in a separate building. Sorry about no picture, I did attempt one but this was at the end of the inspection and my batteries went dead (ran out of spares). Any further help you can give to clarify some of these issues would be great. Thanks for your reply
Originally Posted By: jtedesco This post was automatically imported from our archived forum.
mpettitt wrote:
Joe, you are absolutely right, I should have mentioned that it was plastic conduit. I have to admit that I've been struggling with this issue concerning when it is okay for the neutrals and grounds to be bonded in a sub-panel in a separate building. Sorry about no picture, I did attempt one but this was at the end of the inspection and my batteries went dead (ran out of spares). Any further help you can give to clarify some of these issues would be great. Thanks for your reply
OK, so you are saying that the PVC had only three wires installed, one grounded (neutral) and two hot legs?
Originally Posted By: bbadger This post was automatically imported from our archived forum.
Greg Fretwell wrote:
BTW a phone line is NOT a metallic path since it isn't bonded in the second building
Greg I agree it probably won't be bonded in the second building however I am fairly certain that NEC 830 requires them to be via the primary protectors that are never installed. 
-- Bob Badger
Electrical Construction & Maintenance
Moderator at ECN
Originally Posted By: Greg Fretwell This post was automatically imported from our archived forum.
pdickerson wrote:
Mike,
Make sure that there is no conductive path between the two buildings. Water pipes, chain link fences, and concrete sidewalks might provide a path for return current through the grounding system.
This would only be an issue if the fence or the rebar in the sidewalk was "bonded to the grounding system" at both ends.
This was tossed around for a while on some other boards and that language from 250.32(B)(2) was ciited
Originally Posted By: mpettitt This post was automatically imported from our archived forum.
Joe, yes that is correct. By MBJ do you mean a main breaker, if so then no, just 4 single pole 20 amp breakers. Here is another thought that may come into play. The separate building, main panel and sub-panel are all modern (appears to be brand new), no other electrical problems throughout home or separate building. The separate building is constructed in such a way as the exterior metal siding is exposed on the inside. The sub-panel is attached directly to this metal siding.
Originally Posted By: rcooke This post was automatically imported from our archived forum.
My thoughts you should only have one ground to a system . If you take a feed out to another building you must also carry the ground with it . If you put in a second ground you can run into what is called Eddie currents.
Years ago I ran into a place where horses would never go between two building and this was the reason .
Originally Posted By: bbadger This post was automatically imported from our archived forum.
rcooke wrote:
My thoughts you should only have one ground to a system . If you take a feed out to another building you must also carry the ground with it . If you put in a second ground you can run into what is called Eddie currents.
For better or worse this is what happens between any group of homes fed from a common transformer.
-- Bob Badger
Electrical Construction & Maintenance
Moderator at ECN