Ron-ski
Solar Enthusiast
Z Beny installed in my system
Safely using MCB (mini circuit breakers) for PV & Bi-Directional Battery Protection
- Thread starter LifeWAT
- Start date
That's not a breaker, it's an isolator.
Ron-ski
Solar Enthusiast
You sure about that???? Why do you think that?
The manufacturer specifically refers to it as an MCB - see the picture below, and specifications attached. It even has a trip curve in the specs. I also use Z Beny's larger moulded case breakers for my batteries.
In my use case its used as an isolator for a fused combiner box, each positive and negative of each string is individually fused. My batteries also have T class fuses, and a breaker. I also have these MCB's between the busbar and MPPT's.
Z Beny is one of the few manufactures that appear to specifically mention no polarity and that they are for PV, hence there is no + or - marked on the diagram.
You're right, I thought it was just an isolator because of the symbol on the front. I didn't realized you had different symbols; here the symbol looks like this:
The square and rounded parts indicate it's a thermal-magnetic breaker.
Sorry for the confusion
The square and rounded parts indicate it's a thermal-magnetic breaker.
Sorry for the confusion
Ron-ski
Solar Enthusiast
@BiduleOhm To be honest apart from the switch part of the diagram I've got no idea what the other symbols mean, I just ordered what I considered was appropriate parts going by the manufacturers description, well the second time round anyway.
Sleeper85
Sunday handyman
- Joined
- Nov 28, 2022
- Messages
- 503
Personally, the question I ask myself is at how many amps the thermal protection will come into operation.
Regarding the MCCB TOMZN I don't even know its trip curve.
Is it B, C or D?
No technical information which is a shame.
Even in the case of curve B we can imagine that a MCCB of 100A will not trigger before perhaps 300A.
Below is an interesting article on the subject.
www.gses.com.au
Edit : TOMZN's answer, "should be" a C curve ?
That said, this does not matter in my opinion, the cables must be sized to support the maximum power of the solar charge controller and the inverter, it could never be greater. The usefulness of this breaker will therefore be to be able to isolate part of the system (I use it for my battery) and above all to interrupt a short circuit which the magnetic part will do instantly. On the other hand, for the thermal part, you will probably never see it trigger in the event of over-current.
Regarding the MCCB TOMZN I don't even know its trip curve.
Is it B, C or D?
No technical information which is a shame.
Even in the case of curve B we can imagine that a MCCB of 100A will not trigger before perhaps 300A.
Below is an interesting article on the subject.
Moulded Case Circuit Breakers Explained - GSES
As installed system capacity continues to increase in the Australian PV market, it is valuable for system designers and installers to understand the mechanisms behind moulded case circuit breakers, and the meaning behind their ratings. A moulded case circuit breaker (MCCB) is a type of...
www.gses.com.au
Edit : TOMZN's answer, "should be" a C curve ?
That said, this does not matter in my opinion, the cables must be sized to support the maximum power of the solar charge controller and the inverter, it could never be greater. The usefulness of this breaker will therefore be to be able to isolate part of the system (I use it for my battery) and above all to interrupt a short circuit which the magnetic part will do instantly. On the other hand, for the thermal part, you will probably never see it trigger in the event of over-current.
Last edited:
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