Combiner box

[Dennis 1]

I have a question I have 2 sets of 4 -100watt panels in series going to a Midnight Solar Combiner Box and each panel is VOC of 22.6V and Isc of 5.86A should I have a 15, 20, or 25 amp circuit breaker in the combiner box. Then this will be going to a 150/60 Charge controller which I'm hoping will be alright.

 

[pvgirl]

Assuming this is a config of 2 parallel strings of 4 panels in series.. With only 2 strings in parallel no separate protection is needed per string, and they can simply be connected together. You can put a 20 amp breaker after they combined to provide a disconnect.

 

[MisterSandals]

should I have a 15, 20, or 25 amp circuit breaker in the combiner box.

What is the max fuse size listed on the back of your panels? This is the correct size.

And @pvgirl is correct, a fuse/breaker is not required on each string (only when 3 or more strings in parallel).

Individual string breakers can be handy should you need to work on a single string.

 

[MaikaiLifeDIY]

I think you meant 100-watt panels. If you have two strings in parallel you have approximately 11.72 amps. Using the 125% rule, take 11.72*125% = 14.65 amps, then use the closest breaker size, larger than your calculated amps. In this case, it would probably be a 15-amp breaker.

Like the other posts, this would be for disconnect not between the parallel strings.

 

[Dennis 1]

I think you meant 100-watt panels. If you have two strings in parallel you have approximately 11.72 amps. Using the 125% rule, take 11.72*125% = 14.65 amps, then use the closest breaker size, larger than your calculated amps. In this case, it would probably be a 15-amp breaker.

Like the other posts, this would be for disconnect not between the parallel strings.

Thanks, I changed it, my mistake