Subpanel feeder breaker size?

[Artimuskillz]

This is a solar tie in generating 22 amps max current, hence the 25a/2p breaker on the subpanel but is there any reason the breaker feeding the subpanel has to be an 80a/2p? Can it be a 50a/2p?

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[pc1966]

This is one for one of our USA members such as @Megawatt

Having two MCB (breakers) in series will not give you good selectivity, i.e. the ability for a downstream fault to be cleared only by the downstream breaker (25A in your case), usually the upstream breaker (here 80A) will also go on a hare fault that reaches the "instant" magnetic trip point of the upstream breaker.

Achieving good selectivity with breakers requires the upstream one to be one of the fancier MCCB that has a short-term delay that gives the downstream one a chance to clear first. That is unusually outside of industrial installations.

If your sub-panel has nothing but the solar panels and some trivial other circuits I can't see what a 50A feed is a problem, but this side of the pone the regulations differ.

Also it is odd not to show the N-E link on the main panel (i.e local earthing/grounding of the supply neutral/cold line).

 

[Megawatt]

This is a solar tie in generating 22 amps max current, hence the 25a/2p breaker on the subpanel but is there any reason the breaker feeding the subpanel has to be an 80a/2p? Can it be a 50a/2p?

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It all depends on the rating of the panel like 60 amp or 125 amp panels. You can never exceed the rating of the panel so having said that you can use what size breaker you want to as long as the wiring corresponds to the breaker and the loads being used.