Flex bond

[normbac]

have a indoor D/Y 120/208 transformer about four foot above the panels. I was going to use
2 in. aluminum flex from the 400 amp 480/277 MDP on the primary and also 4in. Flex on the secondary side. Flex is about 5-6 ft long each side. Question: will I have to put bond bushings on the flex connectors. No coencentric
TIA

 

[infinity]

No, although I see them all of the time on these installations. I equate using them to installing bonding bushings on PVC since the flex doesn't even qualify as an EGC just like PVC.

 

[normbac]

No, although I see them all of the time on these installations. I equate using them to installing bonding bushings on PVC since the flex doesn't even qualify as an EGC just like PVC.

Thanks another quick question I am confused on whether to Bond the gas pipe actuall bonding in general. I was going to bond the case from xo and the building steel truss but should I also bond the gas and water and if water does it need to be within 5 ft of entrance?

 

[infinity]

If the structural steel qualifies as an electrode then it must be part of the GES. So if it's already bonded to the water pipe electrode then you can run your GEC from the X0 to nearest building steel. Unless your referring to CSST a separate gas bond is not required.

 

[normbac]

If the structural steel qualifies as an electrode then it must be part of the GES. So if it's already bonded to the water pipe electrode then you can run your GEC from the X0 to nearest building steel. Unless your referring to CSST a separate gas bond is not required.

I am getting my primary from existing exterior switchgear that is feeding two units same structure. the steel truss is bolted onto block wall ( cmu) how do I determine if it qualifies as ges Also don't remember what csst stands for. the inspector did a job inspection on rough in walls and when he walked by the gear partially installed he asked if The gas and water would be bonded or if they were bonded at gear, I said I would check, he did not seem to have answers when I asked about bonding and since I am novice in this area I wanted to get more info before debating issue. Any info is appreciated.

 

[augie47]

are the steel trusses supported solely by the concrete walls with no columns to the slab or footer ?
If so it is commonly not bonded or considered an electrode.

 

[normbac]

Yes there is column support Can you advise on water and gas

 

[ActionDave]

Yes there is column support Can you advise on water and gas

Is the water pipe in the same room as the transformer?

Gas is not required.

 

[normbac]

Is the water pipe in the same room as the transformer?

Gas is not required.

Yes water runs right by it so should i bond it per 250.66
also can elaborate on gas not needing bond

 

[infinity]

Gas:

250.104(B) Other Metal Piping. If installed in, or attached to, a
building or structure, a metal piping system(s), including
gas piping, that is likely to become energized shall be
bonded to the service equipment enclosure; the grounded
conductor at the service; the grounding electrode conduc-
tor, if of sufficient size; or to one or more grounding elec-
trodes used. The bonding conductor(s) or jumper(s) shall be
sized in accordance with 250.122, using the rating of the
circuit that is likely to energize the piping system(s). The
equipment grounding conductor for the circuit that is likely
to energize the piping shall be permitted to serve as the
bonding means. The points of attachment of the bonding
jumper(s) shall be accessible.

 

[ActionDave]

Yes water runs right by it so should i bond it per 250.66
also can elaborate on gas not needing bond

It's like Infinity said....Only the first five feet of the water pipe count as a grounding electrode and that should be bonded at the service which should be bonded to the building steel.

250.104 says that any gas pipe is bonded by the branch circuit that serves it so it does not need an extra connection.

 

[normbac]

Ok starting to get this (starting) Sds bonding should only be if the steel, or water is considered an electrode ?? Water would normally be bonded at the gear and therefore does not need bond at sds Gas is bonded by circuit serving appliance since it not considered an electrode. Am I getting close:dunce::dunce::dunce:

 

[ActionDave]

Very close. SDS needs a grounding electrode conductor just like a service but the rules are relaxed a little bit.

Do you have access to the NEC handbook? Even a really old copy will do.

 

[normbac]

Very close. SDS needs a grounding electrode conductor just like a service but the rules are relaxed a little bit.

Do you have access to the NEC handbook? Even a really old copy will do.

Yes have 08 on computer Old brain needs pictures (mike holt style) or people like you guys explaining over and over
So at sds i need to find a gec or does the egc from the gear to xformer work

 

[normbac]

Yes have 08 on computer Old brain needs pictures (mike holt style) or people like you guys explaining over and over
So at sds i need to find a gec or does the egc from the gear to xformer work

Disregard found answer under 250-30