Talk:Circuit-breaker ( full page )/Archive 1

Hello

I think, that there is made a mistake by 'Rated impulse-withstand voltage (Uimp)'

For industrial devices we can really speak about Uimp=8kV, if we speak about overvoltage category IV and nominal voltage 690V. But domestic devices standard do not know voltages over 3x400 V and highest overvoltage category there is III. So - correct 'usual' Uimp by those installation is 4 kV. Some (selektive) Main CB-s are rather exceptions of that rule.