Immersion Heater Wiring

[Andrew Gabriel]

No RCD protection, but make sure your earth bonding is up to spec.

I don't have a clear picture of your intended setup, but if the max load is 3kW, that sounds fine, except you want the isolator to also isolate the controller for maintenance purposes.

I would expect the instructions would indicate this sort of thing. If the immersion heater load goes through it, then I see no point. If it just takes a low current control supply with volts-free relay contacts, then an FCU with 2A fuse would be a good idea.

[Chris J Dixon]

As part of my central heating refit, I am having a new and relocated hot water tank with economy 7 and boost immersion heater elements. I plan to feed these via a Horstmann electronic timer.

The circuit will have a dedicated 16A MCB (is the voting for RCD protection or not?)

What are the requirements for further protection? I can't see the logic in having a separate fused outlet for each element, but local isolators at the point where the high temperature flexible terminates seems sensible. Should I fit a fused spur unit upstream of the timer instead?

Chris

[Chris J Dixon]

The tank will be in the integral garage, so for convenience I want the controller in the pantry, about 3 metres away, as the cable runs. Max load is indeed 3 kW, as the controller ensures the two elements cannot be in use simultaneously.

Pretty lightweight on those aspects. I'm not sure exactly what the regs require.

Chris

[Lurch]

On Fri, 09 Jul 2004 19:59:27 GMT, Chris J Dixon strung together this:

IIRC the Horstmann timers have integral fuses so a DP switch feeding the timer would suffice. The immersion heaters themselves will need a DP switch each, located near to the tank.

[raden]

In message , Lurch writes

AKA pcb track

I'm not so sure you're right there

[Lurch]

On Wed, 14 Jul 2004 21:44:11 GMT, raden strung together this:

Well, it was a while since I fitted one, I've got six in the garage but can't be arsed to check at the moment. Might be worth the OP just confirming the need for a fuse, or not, before installing.