Maximum wire size for DC Circuit Breaker in a PV Combiner Box

[DEEP NNN]

I'm finding it quite difficult to nail down wire size specification for DC Circuit Breakers. I'm most interested in the type we see in PV Combiner Boxes on Amazon as well as WATTS247.com. I've sent queries to several vendors. Anyone on here with hands on experience?

I'm running AWG 4 wire 50 feet x 2 from my charge controller to a future 12V PV panel install. All my gear is 12V and that is not going to change.

So can anyone tell me if AWG 4 wire will fit into a typical DC Circuit breaker? I've seen youtube videos where it was mentioned they were using AWG 4
wire but I'm having doubts.

This all affects which combiner box I use because, if I need to add a small bus bar to change wire size, the box will need the room.

 

[Supervstech]

Probably depends on the breaker amperage.
#4 should fit most sizes above 30A

 

[PreppenWolf]

I am using AWG 6 in my WATTS247 combiner. You can likely squeeze in AWG 4 but it will be a "fun" time.

 

[DEEP NNN]

Probably depends on the breaker amperage.
#4 should fit most sizes above 30A

A lot of these boxes come with 63A circuit breakers.

 

[DEEP NNN]

I am using AWG 6 in my WATTS247 combiner. You can likely squeeze in AWG 4 but it will be a "fun" time.

Yeah, not the fun time I'm looking for. Lol. Thanks.

 

[MichaelK]

Midnite makes breakers that can handle up to 2 gauge wire.

MidNite Solar 100 Amp 150Vdc DC DIN Mount Circuit Breaker MNEPV100 - FREE SHIP! | eBay

MNEPV100 100 Amp 150 VDC Din Rail Mount Breaker - 26mm Wide. Midnite Solar MNEPV100 100 Amp 150 VDC Din Rail Mount Breaker - 26mm Wide. Always use a properly sized breaker for disconnecting. MidNite breakers have been evaluated by ETL to 150VDC and are listed for US and Canada.

www.ebay.com

 

[DEEP NNN]

Midnite makes breakers that can handle up to 2 gauge wire.

MidNite Solar 100 Amp 150Vdc DC DIN Mount Circuit Breaker MNEPV100 - FREE SHIP! | eBay

MNEPV100 100 Amp 150 VDC Din Rail Mount Breaker - 26mm Wide. Midnite Solar MNEPV100 100 Amp 150 VDC Din Rail Mount Breaker - 26mm Wide. Always use a properly sized breaker for disconnecting. MidNite breakers have been evaluated by ETL to 150VDC and are listed for US and Canada.

www.ebay.com

Thank you.

I also just found out that WATTS247 use a Jiuce JCB3-63 which has in its .

Terminal size top/bottom for cable

25mm2 / 18-4 AWG

 

[SniperX]

I am using AWG 6 in my WATTS247 combiner. You can likely squeeze in AWG 4 but it will be a "fun" time.

Do you think the fuse size in the combiner box is ok? 15A? Or can you swap that out for 20A? I have a 4-2 from Watts247 but I wondered if I am only using half of the box, can I use 20A fuses for the two strings instead of the 15A? It stays under the 63A... I would take the other 2 15A fuses out and not use them. My strings should really have an 18A fuse by the math.

 

[PreppenWolf]

I am not sure honestly. I would call Watts and ask them. They have always been super helpful.