25 feet tap conductor

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hhsting

Senior Member
Location
Glen bunie, md, us
Occupation
Junior plan reviewer
I have 1600A main breaker feeding a wireway trough inside building. The trough is tapped six times. One of the taps is more than 10 feet long but less than 25 feet and terminate in 400A disconnect fused at 200A. The tapped feeder cable is 2 sets of 250 kcmil AL.

I have inspector who came out and said feeder tap cable ampacity does not comply per 25 feet tap rule. However he didnt say anything about 200A fuse size in 400A disconnect.

I guess he is talking about 1600/3 = 533A
So feeder tap cable size should be 2 sets of 500 kcmil.

I dont get why he didnt say anything about 200A fuse in disco. Is he right? Can you sill have 200A fuse in the fused disconnect or that needs to be upgraded? If upgraded then to what?
 
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infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Yes he's correct. The tap conductors have to comply with the 1/3 ampacity rule, the fact that you have a smaller OCPD is irreverent.
 
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