25-06-2020, 03:02 PM
RCDs that cover a number of circuits are usually double pole. When they trip you lose half your circuits. When you have turned off an MCB to work on a particular circuit and accidentally short neutral to earth there's a good chance the RCD will trip and disconect several unrelated circuits.
My own house has the deluxe option of separate RCBO for each circuit. An RCBO is a combined MCB and RCD. But they are only single pole. No nuisance trips from other circuits but the neutral of the circuit I'm working on can still have a voltage on it. Technically it's still live.
Strictly we should use the terms "phase" and "neutral", as both are regarded as "live" in the wiring regs. I've just checked and this usage is defined by the IEC, not just locally in the UK.
My own house has the deluxe option of separate RCBO for each circuit. An RCBO is a combined MCB and RCD. But they are only single pole. No nuisance trips from other circuits but the neutral of the circuit I'm working on can still have a voltage on it. Technically it's still live.
Strictly we should use the terms "phase" and "neutral", as both are regarded as "live" in the wiring regs. I've just checked and this usage is defined by the IEC, not just locally in the UK.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
