DC vs PV Solar Disconnect wiring difference?

[LionKing]

Looking into a 1000V DC MCB for solar string because string voltage is around 600V. Came across this breaker and it has different wiring recommendation for DC system vs PV wiring (which is also DC), so confused about the reason for difference. It seems its only isolating negative in case of DC Equipment, But Not in the case of PV wiring. Does anyone know why? I was under the impression both, positive & negative, need to be isolated.

 

[12VoltInstalls]

It seems its only isolating negative in case of DC Equipment, But Not in the case of PV wiring. Does anyone know why? I was under the impression both, positive & negative, need to be isolated.

I’m not reading that diagram that way.

I’m assuming that the Letter Monikers A-F are expounded upon in the instructions for that breaker. I’d peruse the instruction sheet until you make some correlations as to what the diagrams are referenced to.

 

[timselectric]

The diagram labeling is actually backwards. A & B is what is required for isolated PV circuits. And C thu F are acceptable for DC loads.