I bought a new consumer unit for €65 and it came with various mcb's and one rcd.
Q1: Why are the lighting MCB's rated at 10A? - Should they not be 6A to protect the 1mmsq and 1.5mm sq cable in the event of overload? Or does it really matter that much?
Q2: Why are light circuits not wired via an RCD? You could potentially give yourself a shock if your being careless with rewiring lamps or doing drilling work on a floor above a ceiling. And sure some switch plates are metal, same for some light fittings. Would it not be best practice to run these circuits from the main RCD that protects sockets? Or is it to ensure that lights remain on for basic safety in the event of a ring main fault to earth?
Q3: Why are 40A shower MCB's protected with there own dedicated RCD/MCB switch? Is this for reaction times being that bit more critical in a shower situation or is it because a shower potentially pulling 37A (8.5kW Triton) if shared with load on ring main circuits could cause an unbalance in the circuit thus tripping the RCD when not required?
Q1: Why are the lighting MCB's rated at 10A? - Should they not be 6A to protect the 1mmsq and 1.5mm sq cable in the event of overload? Or does it really matter that much?
Q2: Why are light circuits not wired via an RCD? You could potentially give yourself a shock if your being careless with rewiring lamps or doing drilling work on a floor above a ceiling. And sure some switch plates are metal, same for some light fittings. Would it not be best practice to run these circuits from the main RCD that protects sockets? Or is it to ensure that lights remain on for basic safety in the event of a ring main fault to earth?
Q3: Why are 40A shower MCB's protected with there own dedicated RCD/MCB switch? Is this for reaction times being that bit more critical in a shower situation or is it because a shower potentially pulling 37A (8.5kW Triton) if shared with load on ring main circuits could cause an unbalance in the circuit thus tripping the RCD when not required?