How to change a fuse on a plug socket

[ericmark]

OK 13A 2.42Ω for ELI and 3A 16.4Ω for ELI however in most cases a direct short will either take out the MCB or the RCD or both. What we all want is when some thing faulty is plugged in the fuse ruptures rather than we lose the supply circuit. In the days of a fuse box that worked, but today a MCB or RCD is in the main faster than a fuse, so in real terms the fuse only protects from over load, it does not protect from a short circuit.

 

[JohnW2]

OK 13A 2.42Ω for ELI and 3A 16.4Ω for ELI however in most cases a direct short will either take out the MCB or the RCD or both.

Exactly. The circuit's MCB will nearly always provide adequate fault protection for everything. Only if the Zs at the socket were incredibly marginal would the Zs at the end of the cable plugged into the socket be too high for the circuit's OPD to give adequate fault protection to that cable.

What we all want is when some thing faulty is plugged in the fuse ruptures rather than we lose the supply circuit. ...

Whatever we might "all want", as you go on to say, that is probably an unrealistic expectation when the OPD is an MCB. Furthermore, although it's not impossible that, in the case of a true 'fault' (with fault current = PFC), a BS1362 fuse might blow before an MCB operated, I'm not sure that it would make much difference whether it were a 1A or 13A fuse.

Kind Regards, John