question

nesswill avatar image
nesswill asked

Circuit Breakers for 500vdc @ 20amps

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.

Solar Panel
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5 Answers
luphi avatar image
luphi answered ·

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

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nesswill avatar image nesswill commented ·
Thanks for your reply but i have done all that, what i am asking is for recommendations for what people here have or are using.

Typically these searches find the cheapest option and not what professional use.

Regards, Dave.

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JohnC avatar image JohnC ♦ nesswill commented ·
Hi @nesswill

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.


1 Like 1 ·
nesswill avatar image nesswill JohnC ♦ commented ·

Thanks John.

Yes that looks like what i need just need to see if the Australia Battery shop will ship to the UK as i can not find that anywhere here.

Thank you again for your advice.

Dave.

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nesswill avatar image nesswill nesswill commented ·
@ John i also sorted my SOC thanks to you, now have 16.5kw of Solar and 1820Ah of AGM batteries, completely off grid now in the UK and in January!!

Cheers, Dave.

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JohnC avatar image JohnC ♦ nesswill commented ·

@nesswill

Haha, good work.

I just went for a look for that device on google for UK. EBay bobbed of course, and amazingly, Energy Connections is my own supplier in OZ with a free delivery price in those Pound things. They're legit, Victron dealers too, and I've used them for over 10 years.

https://www.ebay.co.uk/itm/392912244103?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20200818143230%26meid%3D89aad8aaaa784c1a9f98b2a3db17ddb6%26pid%3D101224%26rk%3D2%26rkt%3D5%26sd%3D261991768549%26itm%3D392912244103%26pmt%3D0%26noa%3D1%26pg%3D2047675%26algv%3DDefaultOrganicWeb&_trksid=p2047675.c101224.m-1

You may need to look at the voltage per pole thing though to see if this is suitable for you.

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nesswill avatar image nesswill JohnC ♦ commented ·
Thanks John.
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Michelle Konzack avatar image
Michelle Konzack answered ·

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.

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nesswill avatar image nesswill commented ·

Hi Michelle , thank that is helpful i will look into them,

Thanks again,

Dave.

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sharpener avatar image
sharpener answered ·

Or this from Kraus + Naimer, reputable brand, 650V at 20A.

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nesswill avatar image nesswill commented ·
Thank you.
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Al avatar image
Al answered ·

@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:



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Phil Gavin avatar image Phil Gavin commented ·
Steer clear of magnetic arc quenching on DC MCBs. The magnets make the MCB unidirectional.

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.

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nesswill avatar image
nesswill answered ·

Thanks to everybody who has helped me with this.

Dave.

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