Hello! I am planning a trip to Great Britain in May and came across a
useful piece of information in the Fodor's 98 London travel book. In
the Gold Guide, on page XIX, travelers are reminded that "the
electrical current in Great Britain is 220 volts, 50 cycles alternating
current," and that continental-type plugs are needed, with two round
prongs.
To prepare, I went to Radio Shack to purchase the adapter and converter.
They asked me where I was going, checked their list, and provided me
with a continental-type plug. Now, to the dilemma.
Last night I was reading the "Britain, How to Plan Your Vacation"
provided to me recently by the British Tourist Authority. In their
Factfile section, on page III, they say that "the electrical voltage in
Britain is 230v, 50 cycles. So a three square pronged adapter plug
and/or an electric converter for applicances is required."
So, which is it, three sqaure or two round? Talking with one person who
has traveled over to England to visit the locals, she recalls that the
wall sockets required the three square pronged adapter plug.
I'd appreciate it if someone could help to clear this up!!

It's a big, clunky three square. On the "continent" it's the two round. Check the appliances you're taking, many, razors, hair dryers, video camera chargers, have a switch from 110 to 220 built in.

Yep, 3 square's the one.

Electricity in the UK is nominally 230v 50 cycles (hertz) but anything rated between 220 and 250 should run OK. Plugs are three pin, two horizantal rectangular pins for live and neutral and one larger vertical rectangular pin for earth laid out in a triangular shape. In bathrooms you'll often find sockets for razors which accept two round pins and these often accept the the two flat-pin plugs as well. Lightbulbs generally have bayonet fittings rather than screw threads. Three pin sockets are normally rated at 13 amps and lighting circuits are normally rated at 5 amps.