Wire size for heater

[Sierrasparky]

Hey just curious as to what others think?
what size wire (Cu) is minimum requirement for a 4,000 watt wall heater. No derating issue for voltage drop.

 

[jumper]

What voltage?

 

[Sierrasparky]

240v

 

[jumper]

# 10.

 

[david luchini]

I agree with Der?k, from 424.3(B), 210.20(A), & 240.4(D).

 

[Sierrasparky]

Just as I thought! 30 amp minimum wire ampacity and standard breaker size. I was asking because where I work mostly we use electric for heating. TIme and time again I see 4,000 watt cadet heaters on a 20 amp circuit. Sometimes I see melted connections.

 

[petersonra]

Just as I thought! 30 amp minimum wire ampacity and standard breaker size. I was asking because where I work mostly we use electric for heating. TIme and time again I see 4,000 watt cadet heaters on a 20 amp circuit. Sometimes I see melted connections.

4000/240=16.7 amps.

It should work fine on 20A circuits without melting the connections. If you are melting a #12 wire with under 17A load, there is something else wrong.

I agree it should be sized as a continuous load so it can't legally be on a 20A circuit.