Circuit Breaker recommendations


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Godoh
Senior Member

Joined: 26/09/2020
Location: Australia
Posts: 169
Posted: 06:13am 17 Nov 2021      

I have just installed an 8010 based 5kw inverter in our place. I bought a 120 amp automotive/marine type circuit breaker to mount on it for safety, just in case it decides to emit smoke. Which all of my powerjacks over the years have done!
I checked it today and found that the 120 amp breaker was tripping at 85 amps. Not good as at times I want to run 2.4kw loads for short times.
I am wondering if any folks here have any suggestions of brands or types of circuit breakers for inverter protection.
I have a couple of DC rated 63 amp two pole breakers but need more current than they can hold.
It seems that 120 amp or 150 amp industrial type breakers cost almost as much as an inverter.
Thanks
Pete

Solar Mike
Guru

Joined: 08/02/2015
Location: New Zealand
Posts: 963
Posted: 06:43am 17 Nov 2021      

I have used these  125A and they seem ok, they have quite strong blowout magnets inside for arc quenching, unlike other cheap brands.

Better and what I'm using now are these , a lot more robust and available in quite high currents.

Those cheaper rail mounted breakers have to be kept cool, by using 50mm^2 cable to act as a heatsink, don't place them in a small box or jammed in with others as they will get hot and trip prematurely.


Cheers
Mike
Edited 2021-11-17 16:45 by Solar Mike

Godoh
Senior Member

Joined: 26/09/2020
Location: Australia
Posts: 169
Posted: 07:17am 17 Nov 2021      

Thanks Mike, the big ones look good. I like the BluSunSolar ones, it is much better to be able to use lugs on the cables and bolt them to the breaker. I have had too much trouble with the normal breakers that just clamp the cable, especially on heavy battery cables.
I will chase some of them up.
Thanks again
Pete

wiseguy

Guru

Joined: 21/06/2018
Location: Australia
Posts: 698
Posted: 11:01am 17 Nov 2021      

Very timely, I am also looking for 80/100/120A circuit breakers, when I saw these.

I am still trying to work out their polarity information (maybe they are too....)

Does this make sense to anyone else - maybe Solar inverter refers to the switch ?  Is it April 1st ?


Edited 2021-11-17 21:03 by wiseguy

Godoh
Senior Member

Joined: 26/09/2020
Location: Australia
Posts: 169
Posted: 08:31pm 17 Nov 2021      

Hi Wiseguy Mike, the 63 amp breakers I have look like that one.
They only have + and - marked on the top too.
That one looks like two single pole breakers with a piece of plastic tying them together. The metal piece on the bottom looks like a link.
Surely they are not suggesting to hook two breakers in series?
I have seen breakers with polarity markers before, some are pretty confusing too. I believe they are set up to work properly to extinguish the arc when they are connected in the correct way. Although I have seen some on Grid connected setups connected incorrectly.
I reckon the polarity markers on that one are just showing current flow.
They usually don't come with any paperwork so one can only guess and connect them in the way they are marked.
Pete

Solar Mike
Guru

Joined: 08/02/2015
Location: New Zealand
Posts: 963
Posted: 08:34pm 17 Nov 2021      

Polarity can be tricky, here is an article on the correct way to wire them Link ,electricians it seems cannot follow these simple instructions thus the reason for the regulation changes to allow only NON-polarity types in solar or DC installations.

Cheers
Mike

wiseguy

Guru

Joined: 21/06/2018
Location: Australia
Posts: 698
Posted: 09:07pm 17 Nov 2021      

When wiring in a single breaker with polarity marked on at least one terminal regardless whether placing it in series with the positive or negative lead it is easy to  consider what is regarded as the source and connect it appropriately. But to see a dual breaker with  the positive & negative looking inverted at the other end just doesn't look or feel right.  If you consider each breaker in isolation it does make sense but the markings look like a mistake has been made.

I can imagine many issues being made by the uninitiated, if you intuitively connect the Load red wire to the terminal marked positive the results are bound to be not real good.

If they put the word "source" or "if source" at each end and encompassing the polarity markings I think it would help those unfamiliar to understand the markings.

Thanks for the replies and for the link Mike - its no wonder they intend to legislate to go non polarised breakers.  I probably don't need to say I am not licensed to install solar !
Edited 2021-11-18 07:09 by wiseguy

Godoh
Senior Member

Joined: 26/09/2020
Location: Australia
Posts: 169
Posted: 10:10pm 17 Nov 2021      

Hi Wise Mike, if they had just put arrows showing current direction it may have been clearer.
If the supply positive is connected to the + terminal on the top right, then the load  positive is connected to the bottom right terminal. Then the load return (-ve) is connected to the bottom left and the top right connected to the Supply -ve then the current flow should be right.
Yep non polarised would be clearer. But then there would not be so many stuff ups and the inspectors would not have so much fun, getting folks to return and rectify their mistakes.
Cheers
Pete

Godoh
Senior Member

Joined: 26/09/2020
Location: Australia
Posts: 169
Posted: 10:21pm 17 Nov 2021      

I found an Australian supplier for a breaker that is only a bit above the aliexpress price.
Once the freight in included in the aliexpress breaker the prices are pretty similar.
https://sbpe.com.au/products/beny-battery-breaker-160a

Pete

wiseguy

Guru

Joined: 21/06/2018
Location: Australia
Posts: 698
Posted: 12:35am 18 Nov 2021      

  Godoh said  I found an Australian supplier for a breaker that is only a bit above the aliexpress price.
Once the freight in included in the aliexpress breaker the prices are pretty similar.
https://sbpe.com.au/products/beny-battery-breaker-160a

Pete

Thanks for the link Pete I was not aware of them & they look the part & for a good price.

Godoh
Senior Member

Joined: 26/09/2020
Location: Australia
Posts: 169
Posted: 10:56pm 18 Nov 2021      

Just an update on the circuit breaker I ordered.
Unbelievably the breaker arrived at my post office this morning.
I ordered it from SBP Electrical in Melbourne yesterday and it arrived in Tasmania today.
It is a very solid looking breaker with large allen head bolts for the connections.
Also came with mounting bolts and instructions.
Amazing, in these times with slow post I had not expected to see it for at least a week.
The breaker I ordered was a Zbeny 160 amp.
Pete