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.