Do I need a breaker between solar panels and AIO inverter?

[edweather]

At most I'll have three panels in series at 41 VOC each. So total would be around 120 volts if I use them all. Probably will only use one or two panels at a time. It's just a hand truck emergency system. Won't use it much.

 

[littleharbor2]

At most I'll have three panels in series at 41 VOC each. So total would be around 120 volts if I use them all. Probably will only use one or two panels at a time. It's just a hand truck emergency system. Won't use it much.

Looks like you've chosen the right breaker. What is the series fuse rating noted on the solar panels data label? You might be ok with a 15 amp breaker. If you're using 10 ga. wire then 20 is fine too. Being that the breaker will be basically a means to shut down the PV for maintenance 15 or 20 amps isn't really critical.

 

[edweather]

Thanks. Really appreciate the help. The fuse rating (just says fuse rating, nothing about series,) on the panel label says 20A. I am using 10 ga. wire.

 

[littleharbor2]

Thanks. Really appreciate the help. The fuse rating (just says fuse rating, nothing about series,) on the panel label says 20A. I am using 10 ga. wire.

One panel or a series string of 20 panels, same current and fuse rating.

 

[GridFree]

GEYA Mini Circuit Breaker DC,Din Rail 6KA DC MCB (2P 32A 500V)

$14 on amazon

- I love these - they dont come with DIN rail, but that easily available

You could get single pole, but I like the double poll bc you know the Solar panels are really disconnected.

 

[littleharbor2]

GEYA Mini Circuit Breaker DC,Din Rail 6KA DC MCB (2P 32A 500V)

$14 on amazon

- I love these - they dont come with DIN rail, but that easily available

You could get single pole, but I like the double poll bc you know the Solar panels are really disconnected.

Are they rated for switching at full load?

 

[GridFree]

Are they rated for switching at full load?

Yes, look at the specs.

 

[Whats_per_question]

In NZ, a breaker or isolator for your (OP, @edweather) situation would be optional (at ~99v for the array, its ELV [extra low voltage] and does not require the breaker to protect the cable, or to trip. I *always* put one in, even for a single panel, for this reason: If you have to power cycle the controller during the solar day, do you really want to have to find a screwdriver to unscrew a terminal?
Also, you might get significant arcing on the terminal, where-as a proper DC breaker will have an arc-catcher to deal with this.
Also, rebooting the controller might be being done by a novice at the end of a phone, do you really want them unscrewing terminals?

 

[zanydroid]

Nobody’s jumped on the comment about double pole being a nice to have instead of a must have? It’s required on the majority of system types in North America (ungrounded)

 

[Whats_per_question]

Nobody’s jumped on the comment about double pole being a nice to have instead of a must have? It’s required on the majority of system types in North America (ungrounded)

Good point - In NZ, if a breaker or isolator is mandated by the code, then it must be a double pole, and non polarised.
Polarised breakers were OK up to about 2014 i think. There is a massive issue with polarised breakers due to the faults that can occur (usually in the form of a completely disintegrated breaker) if they are installed incorrectly, and "correctly" is difficult even for experienced installers to get right every time, so the solution was to ban them in favour of non polarised.

 

[zanydroid]

Good point - In NZ, if a breaker or isolator is mandated by the code, then it must be a double pole, and non polarised.
Polarised breakers were OK up to about 2014 i think. There is a massive issue with polarised breakers due to the faults that can occur (usually in the form of a completely disintegrated breaker) if they are installed incorrectly, and "correctly" is difficult even for experienced installers to get right every time, so the solution was to ban them in favour of non polarised.

I don’t think polarized is even sensible on parallel strings. So like 90% of the time they’d be wrong or unnecessary…

 

[Whats_per_question]

Certainly in NZ and Australia (Kangaroos, not Mozart) polarised would be illegal for any professional to install, and almost certainly void any insurance if you installed them yourself - its just not worth the risk given that non polarised cost the same.