On Tue, 31 Jul 2007 19:52:40 +0100, Geoff Berrow
wrote:

I've just bought a house which was built in 1965. It has a modern
consumer unit but having just removed a light switch I notice the wires
leading to it are black and red.

At what point does a rewire become necessary?

Just before it kills someone.

If you're concerned you could get it tested to see if it's all working
correctly.
--
http://www.orderonlinepickupinstore.co.uk
Ah fetch it yourself if you can't wait for delivery
http://www.freedeliveryuk.co.uk
Or get it delivered for free