Switch to allow electric shower or electric heating

[purvestj]

Based on the contents of this site, I'm at the installation stage of a heating system into a property I'm refurbishing.

I'm planning on an electric wet central heating system (Amptec) with a direct heated cylinder, but so there is no dependence on the boiler I'm going with an electric shower also.
I recently got the input fuse of the property upgraded from 60A to 80A, but I'm aware of the fact that I'll not be able to run both the shower and boiler simultaneously, and believe there is a product on the market that disables the heating when the shower is activated. Can anyone tell me the name of this product and any links to where I may buy it.

Tom

[sparx]

Hi I don't know of a proprietary one but any suitably rated contactor could be used with the shower supply holding the main contacts to heater 'open' by energising the coil of the contactor.
On reflection I think the AMPTEC unit has a control circuit through it's own thermostat which could be broken by a small relay from shower circuit, as above but much cheaper than heavy duty contactor, electrically simple to do.
Practically it would need care with 2 independant circuits at the relay which would need to be enclosed in a plastic box and fused down & labeled to say
"Two circuits inside, dual isolation required before opening" or similar.
Should be no trouble for a 'Part P' leckie though,
regards Sparx