Hello All. I hope you had a Merry Christmas/ holidays, etc.
My boss's house had a fire last month due to aluminum wiring. Other than that, I don't have details.
I started checking my house and found aluminum 3 conductor 6AWG going to the air handler. An electrician wants to replace this with romex simpull 6AWG copper NM-B.
The air handler is a carrier FV4 and it has 15KW of heat (part of heat pump system). More data:
L1/L2 heater amps: 36.2/40.0 min. ampacity 53.8/58.5 max OC protection: 60/60
L3/L4 heater amps: 18.1/20.0 min. ampacity 22.7/25.0 max OC protection: 25/25
My first question is that the circuit breakers on the front of the FV4 are both 60 amps. One for L1/L2 and the other for L3/L4. Why would L3/L4 have a 60 amp breaker on the front of the unit? Shouldn't it be a 25 amp breaker as per the label? The breakers in the main panel are 60 for L1/L2 and 25 for L3/L4. I suspect that is ok.
Second question is about the NM-B 6/2 wire. I checked the website and it is rated for 55 amps. It seems to me this is not enough for L1/L2? This is the scary part because if copper 6AWG is not enough, then certainly aluminum 6AWG is an accident waiting to happen.
I appreciate your help. I want to be comfortable with what this electrician does.