safety switches

[old brick]

Why do you need a safety switch as well as fuses or circuit breakers in your metre box?

[Bob A Job]

Simple, so you can change fuses or breakers without shocking yourself or turning off the whole street.

[norfolk boy]

Do you mean safety switch as in rcd? Rcd will trip only on earth leakage and fuses will only trip because of too much current being used on that circuit.

[Disco Fever]

As a sparky myself the RCD, (Residual Current Device), is a safety feature that is installed mostly on things like your shower and power sockets in the home for added protection against electric shock. ie if you plug in your electric lawn mower in a socket inside the house then because the mower is not in the home, its outside the equipetential zone so you need to have the mower backed up by the RCD. The RCD picks up a small current that flows between live and earth or neutral and earth in the event of an earth fault. Most earth faults come from, in my experience, kettles, fridges and microwave ovens but the most appliance that trips out the RCD is an iron. Always keep the receipt of an iron when you buy it cause I can guarantee that within 6 months the iron will go faulty and the RCD will keep tripping. Easy when you know innit.