Hi George, you can do that. I have one installed on my rig which is just plugged into my pre-amp. Mainly because, the ELCB came moulded in-line with my kettle lead mains cable. Since the pre-amp is where my first contact with the rig is. I felt that was the best place for it.
I also have a plug in one, ( from B&Q), that I plug my guitar amp into. I too have been the victim of an electric shock on-stage.
Fortunately it was in the USA, (110v), and happened when the singer put his arm on my shoulder whilst holding the mike. We only felt a bit of a tingle, but it did make me think.
I used to be an electrician many moons ago in my early 20's and fortunately have only had one electric shock in the UK that was 240v DC and believe me that hurts big time.
if you are playing anything above a tiny venue in the UK you are likely to find that the building has a 3 phase supply at 415v which gives you 3 different circuits at 240v ac.
This can often result in the PA being plugged into one circuit and the stage backline is plugged into another circuit. If my electrical theory memory is correct, if the earth is lifted on either the stage or pa due to fault or a deliberate act, and you were holding your guitar and a microphone, you would complete the circuit and become crisp..
My electrical theory teacher used to say... Volts Jolts, Current Kills.
Basically, an elcb is designed to cut the circuit before enough current flows to cause injury. They also have a test button on it which it is recommended you check before use.
if you are still worried get a local sparky to check over your rig. You could also get your stuff PAT Tested which should find any problems to do with earthing etc. I got my band stuff done for ?30 which includes 20 items tested and a certificate.
Jazzyvee
(Message edited by Jazzyvee on September 22, 2009)