Installing Gledhill Stainless Lite Unvented Cylinder

[GB]

Installing Gledhill Stainless Lite Direct Unvented Cylinder - I have pretty much decided on one of these (120l) to provide hot water for a shower/basin/kitchen sink.

this a sensible job to attempt to d-i-y? I've done a bit of plumbing, but not huge amounts. Also, is that a sensible choice of cylinder for the money, etc? It doesn't have to last for ages, as the flat will be knocked down within the next 5 years. The present plumbing is completely shot, due to age/misuse.

Also, and I know the practical answer to this: It will be installed (boxed-in) in a corner of the bathroom, with an electrical connection to the immersion heater. Does it need to have a double pole safety cut-out? The practical answer to this is of course do it and don't fuss. But if it's actually not part of the bathroom, as it's boxed in, is that essential (to comply with the law) ?

[Nutkey]

a) Legally, you need to go through buildings control if you're installing an unvented cylinder. You probably also fall under part P, though I can't be bothered looking it up.

b) Are you talking about a double pole switch? I'm pretty sure that the standards say that a means of isolation should be provided (not counting the MCB!). Also, you are probably going to run most of the circuit in T+E - you need to run the final section to the immersion heater in heat-resistant cable, and the switch is the obvious place to change between the two.

[GB]

Thanks for those points. What I meant was an RCD. Oner of these for example:

[Nutkey]

le:

Well if you're running any wiring in a wall, you will need an RCD anyway unless (usally) it's >50mm from the surface, or protected by earthed metal. The RCD will need to protect the wiring, not just the immersion heater.

As for the original question - do you need a RCD if the immersion heater is boxed in? I don't think you do, provided that there are no controls accessible from the bathroom. Under 16th, the bit under the bath was considered outside zones, provided you needed a tool to access it. So it seems to me that a boxed in area wouldn't count as part of the bathroom for the purposes of requiring RCD protection. However, I still think you should be putting in a double pole switch to isolate the immersion heater - and that will need to be accessible from outside the boxing, and will therefore require an RCD.

The immersion heater will be wired on a 20A radial circuit back to the fuse box, so you could just put an RCBO there. If the existing wiring has it on a spur (i.e. bodged) then you could add an RCD at that point, but it's better to have it on its own circuit.

[GB]

example:

>>> Well if you're running any wiring in a wall, you will need an RCD

The existing immersion heater is in the airing cupboard. I'm ripping out the bath and installing a shower. That then gives me room for the cylinder in the bathroom. So, I'm just planning to extend the wiring from the airing cupboard (underneath the shower tray) to the new water heater. I'll do that in heatproof cable, as it's only 3 meters, and I'll stick the RCD in place of the current switch in the airing cupboard. Job done, I think.