60 amp Xantrex CC - 80 amp breakers?

Seanadirondacks

Hello I have a 60 amp Xantrex and I have 80 amp breakers on the positive lines. Are these the correct breakers or should I scale down to 60 amps? Thank you!

Raj174

The main function of the breakers is to protect the wire. That means you have at minimum  #4 AWG wire installed for these connections.

Rick

Seanadirondacks

Thanks Rick I am using #4awg wire. Im unsure if using the 80 amp breaker is the correct choice or if i should be using 60 amp breakers as the CC is 60 amp. Thanks!

mike95490

80A breaker is good for 4ga wire.  If your charge controller melts into a puddle of solder, when the shorting amps reach 80A, the breaker will pop, preventing the wires from causing a fire.   This happens only when the CC is already dead, if it was going to die, 60A or 80A would make no difference.  The breaker is for the wire.

Seanadirondacks

Thanks Mike95490!

Estragon

BUT... if you want to send the puddle to Schneider for a warranty claim, you might want to be able to say you used their recommended breaker size ;--)

Seanadirondacks

I was just reading the manual as its a new CC. Im gonna need #6 wire and a 60 amp breaker! I'll just step down my #4 wire from the bank using a bus bar and bring the #6 to the CC.

Estragon

If the #4 wire physically fits in the controller terminals, I'd go ahead and use it (but with the recommended 60a DC rated breaker).

Seanadirondacks

Good advice! Thanks!

Horsefly

The CC is rated for 60A continuous output.  The NEC rule says that the breaker size should be 125% of the continuous rate. 125% of 60A is 75A. Since you probably can't find a 75A breaker, the 80A is fine. I wouldn't switch it out. If you put in a 60A you will be - strictly speaking - undersizing your breaker.

BB.

It also depends on which brand/model of circuit breaker you use... Most circuit breakers (and supporting wiring) should be 1.25x larger than the highest constant current you expect. For a 60 amp charge controller:

• 60 amps * 1.25 NEC derating = 75 amps (round up to next standard size is 80 amps)

Outback and (I think) have some breakers that are rated for max continuous load (something like 63 amps). In theory, you do not need to up rate them (but you should still use up rate the cabling to ~75-80 amps).

Typically, breakers (and fuses) will not trip at 80% of capacity and will (eventually, minutes to hours) at 100% or rated capacity. But without spec sheets, it is difficult to be sure.

-Bill

Dave Angelini

Schneider lists the battery circuit breaker they sell/make for the mppt 60 at 80 amps and the mppt 80 at 100 amps.