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Posted By: beach Isolated neutral bus bar - 02/27/02 03:23 PM
I had an inspector argue that the nuetral should be isolated but in this situation I believe he was wrong.

3 wire sub fed from 60 amp ocpd from main panel.
Detached garage. Garage has ufer.
Can someone shout out some code.

Thanx,
Jon
Posted By: Redsy Re: Isolated neutral bus bar - 02/27/02 04:32 PM
I think 4 wires are preferrable, but--
What is the raceway material?
Look at 250.32(B)(2).
Also see 250.32(D).

[This message has been edited by Redsy (edited 02-27-2002).]
Posted By: beach Re: Isolated neutral bus bar - 02/28/02 03:07 AM
Raceway material is carlon. 4-wire is niether preferred or needed, the garage has a ufer ground.
Posted By: resqcapt19 Re: Isolated neutral bus bar - 02/28/02 12:58 PM
Are there any other conducotive paths between the 2 buildings?
Don(resqcapt19)
Posted By: Redsy Re: Isolated neutral bus bar - 02/28/02 02:36 PM
250.32(B)(2) seems to justify your installation.

Carflex? Is it buried?



[This message has been edited by Redsy (edited 02-28-2002).]
Posted By: beach Re: Isolated neutral bus bar - 02/28/02 03:37 PM
Don,
No conductive path to the main building that would create a dangerous parallel current path for the line to neutral circuit.
That I why I believe I am correct.

Also this is a all-in-wonder inspector.

Redsy,
No not carflex, carlon schedule 40. Burried at 18" of cover.

Thanks,
Jon
Posted By: resqcapt19 Re: Isolated neutral bus bar - 02/28/02 04:18 PM
If there are only three conductors it becomes very dangerous to isolate the grounded conductor. If the grounded conductor is isolated and there is not an EGC there is no fault clearing path.
Don(resqcapt19)
Posted By: motor-T Re: Isolated neutral bus bar - 02/28/02 06:17 PM
You keep insisting that you have a Ufer ground, this is better than a ground rod but still not good enough to trip a breaker, the grounded(neutral) conductor is used for fault tripping.
If there is no parallel ground paths common to both buildings, then you should be able to run a 3 conductor out there; however if the AHJ wants a 4-condutor, then he will contiinue to gig you until you convince him otherwise.
I personally find it prudent to say ok and do it the way he wants afterall he is the Authority Having Jurisdiction.
-Mark
Posted By: beach Re: Isolated neutral bus bar - 02/28/02 07:34 PM
The wire is already run (3 wire). The inspector does not have a problem with it being 3-wire, his only gig was with the neutral bar being bonded to the ges. I don't want to " say ok and do it the way he wants afterall he is the Authority Having Jurisdiction" because I know this would be a dangerous situation as Don has also pointed out.


250.32 (B)(2)
Clearly defines that I was correct.

My installation fits the 3 criteria.

1. No equipment grounding conductor is run with the supply to the building. (3 wire)
2. There are no continuous metallic paths bonded to the ges in both buildings.
3. There is no ground-fault protection installed on the common ac service.

Under these conditions nec states
" the grounded circut conductor (neutral) 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." NEC 2002

I will bring my code book to the re-inspection and have him read it himself. I can't see how he could interpit it any different.

Than you again for you input.

Jon
Posted By: resqcapt19 Re: Isolated neutral bus bar - 02/28/02 09:52 PM
Jon,
Do not under any conditions allow that panel to be energized without bonding the grounded conductor to the equipment grounding conductors and grounding electrode conductor in the second building. Without this bond there is no fault clearing path and all conductive itmes conected to the electrical system would become hot if there was a ground fault. There is no way to clear this ground fault without the bond. This would be a very very dangerous installation if the bond is omitted. If you are a contractor, you are still subject to law suits if someone got hurt or killed even if the inspector told you not to bond the neutral.
Don(resqcapt19)
Posted By: Electricmanscott Re: Isolated neutral bus bar - 02/28/02 11:01 PM
Bring the book and let him read it. If he can't seem to uderstand at that point maybe it's time to go over his head. County or state official perhaps. I have done this before trying not to be confrontational and it has worked out fine. If you know you are right and I beleive you are you must do the right thing. Who knows what else this guy is having people do. Just because he is an inspector does not mean he actually knows everthing! If he is reasonable he will appreciate being educated.
Posted By: beach Re: Isolated neutral bus bar - 02/28/02 11:38 PM
Thank you for all the responses.

The re-inspection is tomorrow. The panel is energized but the bond from the neutral to the ges has never left the panel (and never will) reguardless of the inspector's wishes. I have had rulings over turned in the past by senior inspectors but only after I am 110% sure I was correct and didn't just interperit it differently, hence the posting in a great forum such as this.

Jon
Posted By: motor-T Re: Isolated neutral bus bar - 03/01/02 12:20 AM
beach
After reading your last post it help clarifies what you did. I guess I am spoiled we have some very good inspectors in my area. Since you have what you say you have then by all means there should be a bonded neutral in the sub-panel.
Can you appeal to a higher authority ? like a state inspector ?
-Mark
Posted By: electure Re: Isolated neutral bus bar - 03/02/02 02:29 AM
beach.
How did you fare? Is the inspector a little smarter?
Posted By: beach Re: Isolated neutral bus bar - 03/02/02 02:51 AM
I had a different inspector today that signed off on the project.

Thank you again.
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