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#210205 - 06/03/13 10:42 AM 250.80
akmaster Offline
Member

Registered: 06/11/12
Posts: 70
Loc: alaska
Hi,
Is there any requirement to ground a 90 degree RGS sweep that is connected to a PVC duct bank and has a PVC riser?

Article 250.80 seems to say that the 90 does not need to be grounded if it is below 18".

250.80 Service Raceways and Enclosures. Metal enclosures and raceways
for service conductors and equipment shall be connected to the grounded
system conductor if the electrical system is grounded or to the grounding
electrode conductor for electrical systems that are not grounded .
Exception: A metal elbow that is installed in an underground installation of
rigid nonmetallic conduit and is isolated from possible contact by a minimum
cover of 450 mm (18 in.) to any part of the elbow shall not be required to be
grounded connected to the grounded system conductor or grounding electrode
conductor .

It seems to me that the sweep should have a rigid riser with a grounding bushing to ground that isolated metal part.


Please quote any article that may require that 90 to be grounded.

This is for the secondary of a transformer...13.8 kV and 4160 VAC from switches to Electrical control rooms with transformers and MCC'S.

Would this be considered a service?

Thank you,

GW



Edited by akmaster (06/03/13 10:47 AM)
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#210206 - 06/03/13 10:53 AM Re: 250.80 [Re: akmaster]
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9012
Loc: Estero,Fl,usa
If it is not going to be exposed to contact (18" down) I can't think of a real reason to bond it. The worms coming up would tip you off if you had a fault.
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#210207 - 06/03/13 11:04 AM Re: 250.80 [Re: akmaster]
akmaster Offline
Member

Registered: 06/11/12
Posts: 70
Loc: alaska
Thanks Greg...would the secondary off a transformer over 600 vac or the feeders from a switch fall under this same rule?

regards

GW
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#210219 - 06/03/13 05:11 PM Re: 250.80 [Re: akmaster]
gfretwell Offline

Member

Registered: 07/20/04
Posts: 9012
Loc: Estero,Fl,usa
I don't see a >600 rule. I guess the worms just jump a little higher if you have a fault.

Actually the fire shooting out of that hole might take birds out of the sky wink
I have seen MV conductors down and dancing up off the ground. It is a sight to see if you have a safe place to watch from. (In my case a roof top bar in the Keys watching them clear out a parking lot). It went on for about 45 minutes before the PoCo showed up to pull the disconnect link.
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#210256 - 06/06/13 08:40 AM Re: 250.80 [Re: akmaster]
akmaster Offline
Member

Registered: 06/11/12
Posts: 70
Loc: alaska
Thank you Greg.

Greg
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