ampacity of a conductor

[nathan01]

Wiring a furnace, there are two 60 amp-240 volt breakers tied together with only one lug each. Would like to know the wire size to feed the heating unit and the optimal breaker size? Approx. 40' from panel to heating unit.

 

[lrollo]

Re: ampacity of a conductor

What is the KVA or KW rating of the heater? I have seen this kind of breaker before. The best thing to do is look at the KVA or KW of the heater and lets go from there.

 

[iwire]

Re: ampacity of a conductor

I agree with Irollo you can not figure the size based on the ratings of the breakers in it.

Try that with a 42 circuit panel filled with 20 amp breakers and you would need a 420 amp feed to the panel. 21 poles x 20 amps = 420 amps

You need to go by the name plate ratings, look at the name plate for minimum circuit ampacity or at least the total KW as Irollo has said.