UK.

This is in round figures.

UK runs 220 Volts. It used to be 240 but our masters which art in Brussels have been standardising things again. In fact actual supplies are often 240V.

A house will have power ring mains, and each such ring main will be fused (or have a cutoff switch) 30 amps at the fusebox (consumer box). So you can get nearly 7KW out of a ring main. But squarepin UK plugs are fused at no more than 13 amps. Call it 3KW. You can't get (well, you can't easily get) the standard size fuse in higher ratings. However, if you WANT to take a chance on melting the plug or the socket you could add a strand or two of wire to the fuse and rely mainly on the fusebox.   In theory you should not melt the ring main or start a fire under the floorboards. Probably. Also, there may be up to four (well, I've never seen more) of those rings on the consumer box.

There well also be lighting rings, probably tripped at 16A but it might be 10 or 6.

Spur mains are permitted under certain circumstances.

You MAY find cooker or shower spurs run in doubled 30Amp housing cable, fused or tripped at 70A at the board, but you shouldn't!


To add a ring or spur can only be lawfully done by a part P certified electrician, and it is illegal to sell a house without a part P certificate. Silly really 'cos any fule who can pass O level physics should be able to sort a basic AC circuit, but some landlord killed a tenant and Parliament intervened..

Do not play about with industrial premises without exact information. A house will only be on one phase of the grid, but industrial premises will often have more than one phase and so potentials can be well over 400 volts. Also the earths of the two phases are often off relative to each other - enough to give a guitarist whose guitar amp is on one phase a nasty but not lethal surprise using a microphone on a PA amp on a different one. They SHOULD both go back to local earth but faults are not that rare.


Agricultural premises are riskier. There will almost certainly be all three phases in there somewhere, and wiring dating from before the first world war, repaired by farmers with hairpins nails and binder string. Farmers never fix anything right.