Bus Duct Tap EGC

[infinity]

I saw this the other day, they have a 1600 amp bus duct with a tap box feeding a 200 amp disconnect switch. The EGC between the tap box and the disco is a #6, (the FMC does not qualify as an EGC and there is a #6 within the FMC). I say it's too small and needs to be #3/0 (the size of the tap conductors) based on 250.122(G). I'm being told that "we always size the EGC according to T250.122 based on the 200 amp OCPD in the disconnect." Yes there several other visible violations.

 

[romex jockey]

just don't get why they want to do that externally, when it can be done internally Infinity

~RJ~

 

[infinity]

just don't get why they want to do that externally, when it can be done internally Infinity

~RJ~

There is an EGC on the inside but it's only a #6. I don't know why anyone would put that jumper on the outside either.

 

[Cow]

I thought Table 250.122 summed it up pretty well when the heading says "......setting of OCPD ahead of equipment, conduit,....."

To which 250.122(G) that you mentioned makes it pretty clear for this installation. This particular code isn't a gray area, or need interpretation, it's pretty cut and dried.

 

[augie47]

"we always" means "we have always been incorrect" in this case. I agree, EGC should be 3/0.

 

[infinity]

"we always" means "we have always been incorrect" in this case. I agree, EGC should be 3/0.

Thanks Augie, et al. I always like to hear other opinions before I run something like this up the flagpole just in case I've overlooked something.