Feeder tap question

[cppoly]

If you have 500 kcmil feeder protected by 400 amp circuit breaker, when you make a feeder tap and terminate to a 400 amp breaker, you need to increase the conductor to 600 kcmils since the ampacity needs to be at least 400. Does this make sense for the feeder tap to be larger than the feeder?

 

[wwhitney]

If you have 500 kcmil feeder protected by 400 amp circuit breaker, when you make a feeder tap and terminate to a 400 amp breaker, you need to increase the conductor to 600 kcmils since the ampacity needs to be at least 400. Does this make sense for the feeder tap to be larger than the feeder?

If you "tap" the 500 kcmil Cu feeder with a 500 kcmil "tap", then it's not a feeder tap, as the 500 kcmil Cu "tap" may be protected at 400A per 240.4(B). So no need to use 600 kcmil Cu, regardless of the rating of the OCPD the "tap" conductor lands on.

Cheers, Wayne

 

[cppoly]

Yes, good point! Forgot about that

 

[infinity]

If you have 500 kcmil feeder protected by 400 amp circuit breaker, when you make a feeder tap and terminate to a 400 amp breaker, you need to increase the conductor to 600 kcmils since the ampacity needs to be at least 400. Does this make sense for the feeder tap to be larger than the feeder?

What you end up with is a splice not a tap. Interesting question, if the feeder conductors were 600 kcmil then would your "tap" conductors also need to be 600 kcmil? No.

 

[cppoly]

Are the tap conductors required to terminate to similar type OCPD devices or can tap 1 terminate in a C.B. and tap 2 terminate in fuses?

 

[wwhitney]

Are the tap conductors required to terminate to similar type OCPD devices or can tap 1 terminate in a C.B. and tap 2 terminate in fuses?

A feeder can have multiple feeder taps connected to it, and the compliance of one feeder tap does not depend on the details of any of the other feeder taps.

Cheers, Wayne

 

[kwired]

Are the tap conductors required to terminate to similar type OCPD devices or can tap 1 terminate in a C.B. and tap 2 terminate in fuses?

Assuming you are talking about different sets of taps supplying separate feeders or branch circuits yes you could have fuses on one and breaker on the other.