The Smallest Tap Conductor?

[Dale Hayes]

What is the smallest gauge 75C tap conductor that can be connected to the load side of a 3-phase 1600 amp circuit breaker?

The breaker will have 3 terminal pads for making the conductor connections and there will be 15 connections to each pad.

The taps are less than 10ft in length.

These "tap conductors" are protected only by the 1600Amp breaker.

Isn't this covered in the 10% Tap Rule of NEC 240.2 1 (B) (1)?

 

[raider1]

I would say the the tap rule in 240.21(B)(1) would cover the taps.

Chris

 

[Dale Hayes]

Raider ... can the (15) tap conductors be as small as 6ga 75C wire?

 

[Dennis Alwon]

I see that a 1600 amp breaker would mean that a 10 tap cannot be less than 160 amp wire. 240.21 (B)(1)(4) states the rating of the OCPD on the line side shall not exceed 10 times the ampacity of the tap conductor.

 

[iwire]

I see that a 1600 amp breaker would mean that a 10 tap cannot be less than 160 amp wire. 240.21 (B)(1)(4) states the rating of the OCPD on the line side shall not exceed 10 times the ampacity of the tap conductor.

Devils advocate.

8 THHN rated 80 amps 90 C column of 310.17, seems like that would do it.

 

[steve66]

Aren't we limited to the 70 deg. column for terminations?

Or even the 60 deg. column for #8??

 

[skeshesh]

Devils advocate.

8 THHN rated 80 amps 90 C column of 310.17, seems like that would do it.

How would 80A be adequate ampacity in this case? 1/10 of 1600A is 160A as pointed out by Dennis.

 

[iwire]

Aren't we limited to the 70 deg. column for terminations?

Or even the 60 deg. column for #8??

I am not sure that we are for this application.

How would 80A be adequate ampacity in this case? 1/10 of 1600A is 160A as pointed out by Dennis.

It would not be, for some reason I had 60 amps in my mind not 160.