Its always been problem free but this morning its started to switch from scalding hot to cold every few seconds. Im kind of afraid there is something wrong with the electrics and i'll get a massive electric shock. Any views??
There is a problem with the thermostatic housing which senses the temperature of the output and adds more cold or hot depending on the settings. Theses days it is cheaper to buy a new shower which will have a guarantee but it is the replacement fitting which costs more.
As long as the shower is properly sealed and the earth is in place the likelyhood is low as it is a fault with the part and not the wiring. I am trained in plumbing and electrics and would never to advise using a faulty shower so get it fixed ASAP as electic and water dont mix.
What sort of shower is it? In some applications, the shower will run hot water only, if someone is using the cold tap in another part of the house - when the tap shuts off, the cold water comes whooshing back to the shower.
I agree with all that has been said by SOTERIOS and the most important thing is that you get it fixed a ASAP.
My only comment is..... Try to get someone who is fully qualified in both Electrics and Plumbing, otherwise you will require the services of two separate tradesmen which will push-up the cost.
To put your mind at rest, Hairy .............. electric shower circuits should be protected by an MCB (or fuse), usually 40-45A. That'll protect you should a fault current occur. It should also be covered by an RCD (trip) to give protection against earth faults. (A bit simplified, but that's the basics)