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Sorry to ask but i want to ensure i get something good, i have looked around and read lots of posts but for here in the UK i can not find something suitable ( well recommend by someone i trust)
So with that said i need to put a Circuit Breaker on each PV string (x4) what is a good quality units to use please, it will be mounted in a barn but it is dry so weather proof is probably not required.
Thanks for your help and patience!
Dave.
DC breakers are not easy to find, nor they are cheep.
I have chosen those fuse holders: https://www.google.com/search?q=abb+e92%2F32
Of course you have to add the right fuses (there are special ones for PV)
Cheers,
luphi
Typically these searches find the cheapest option and not what professional use.
Regards, Dave.
The pros would probably suggest a double-pole breaker for solar. I use Noark d-p 500V/20A, and indeed I added one just a few months ago because it's 11yo mate kept tripping when 20A exceeded (yep, spot on). But I note now that they're only available up to 360V rating.
And there's virtually nothing via google with the low 20A, always much higher A for the 500V spec.
Maybe you should have a look into the
ABB S202M 20B UC
They are made for 220Vdc, but you can double the Voltage by putting the two contacts in series. If you need to disconnect both wires from the Solarpanels, then you have to go with the
ABB S204M 20B UC
Have a nice day.
@nesswill I have used Schneider DC breakers (C60H-DC), they do a 500v 20a, they are pricey, and beware of cheap fakes on Amazon! RS UK stock them amongst others.
I've also used Tomzn Breakers too, they do 1000v DC dual pole breakers.
Both brands seem to be reliable, and use magnetic arc quenching - the cheap fakes don't bother.
Video insight into the inner workings of the Tomzn:
The MCB will fail catastrophically when switching even load current in the wrong direction.
The magnet ensures the arc is sustained instead of quenched. Seek out bi-directional DC MCBs.
@Phil Gavin Yes, don't use Arc quenching DC circuit breakers for Bi-directional circuits I.E. Inverter<>Batteries, but for solar circuits, fine. *Edit: and make sure the + and - connections are connected correctly!
Only use unidirectional MCBs where it is impossible, not where it is doubtful.
If the OP parallels the PV strings at the MPPT, which is likely. Then it is possible to back feed current to a string cable fault from parallel strings.
Thanks to everybody who has helped me with this.
Dave.
