Mains Plug Fuse Rating

For an appliance rated as 700w or less a 3a fuse should be fitted.

Mains plug fuse rating.

13a rating only. Mcru rhodium plated uk plug fuses. Hifi tuning gold audio fuses for uk mains plugs. For example bottle style fuses distinguish between ratings with different cap diameters.

For appliances above 700w a 13a fuse should be fitted. Automotive glass fuses were made in different lengths to prevent high rated fuses being installed in a circuit intended for a lower rating. Plugs for appliances rated between about 700 watts and 3000 watts the maximum rating of a wall socket should be fitted with a 13 amp fuse coloured brown. In practice most bs 546 plugs are unfused with fused versions being unusual and expensive.

So if you have a 240 volt heater rated at 3 kw 3000 watts it will have a load of 12 5 amps therefore it requires a fuse rated at 13 amps. Glass cartridge and plug fuses allow direct inspection of the fusible element. Rated 4 50 out of 5 9 60. The 15 ampere a sockets were generally given a dedicated 15 a circuit.

Manufacturers have now standardised plug fuse ratings to be either 3a or 13a. Plugs fitted with bs 546 fuses have been optional since the original bs 546 1934 with maximum fuse ratings of 2 a in the 2 a plug and 5 a in the 5 a 15 a and 30 a plugs. The problem in most homes is that if a replacement plug top is fitted to an electrical item it will more than likely be fitted with a 13 amp fuse regardless of what the wattage is. These are 20mm long to fit inside uk equipment it is important you fit the same fuse rating as per the original fuse.

If it s a rewireable type plug and the original fuse size fitted by the manufacturer is not known the recommended method is to use the 700w rule.