Wiring for shower pump

[davety04]

Hi, currently replacing my old instant heat shower(very poor in winter) with a thermostatic mixer & pump. Can I use the existing cable(wired direct to consumer unit & fused @ 32A. to power the new pump? Obviously its heavy duty cable (7 strand 3 wires L N E), but can it be extended safely & fused at a lower rate? Excuse my ignorance of electrics!, I'm ok with the plumbing, but want to be safe electrically. Thanks.

 

[ColJack]

since this is work in a bathroom, then the job is notifiable to the LABC under part P of the building regulations..

this will cost you to do and varies from LABC to LABC..

it will probably be more cost effective to get a part P registered electrician in....

 

[electronicsuk]

I assume you're referring to a separate pump rather than an all-in-one pumped shower and mixer. If that is the case, your first task will be to find a suitable location for the pump. If you want to locate it anywhere within the bathroom then you need to take into account the IP rating of the pump and the zone in which it will be installed.

To get power to the pump you will likely be best using a Fused Connection Unit. This should be located outside the bathroom, and you will need to re-route the existing shower supply cable to the FCU, along with a length of 3-core flex to the pump.

Depending on your existing installation, you may need to have an RCD installed to feed the pump. It would also be prudent to alter the rating of the device protecting the shower cable at the consumer unit to something of a rating more suitable for the pump, although due to use of an FCU this isn't strictly required.

In all, I'd take the advice already given and enlist the help of a pro.

 

[davety04]

Thanks for your replies chaps. I was referring to a separate pump, which I plan to site in a large airing cupboard(housing HWCylinder, boiler & electrics also- A trician wired these so Im presuming they were within Regs at least at that time. It seems that he has wired into a lighting ring main to fused box-is this normal practice? It was just that the existing shower cable was there I suppose. All in all, I will take your advice, it ain't worth the risk. TA.

 

[electronicsuk]

It seems that he has wired into a lighting ring main to fused box-is this normal practice?

I assume you mean the electrician has wired a fused connection unit into the radial lighting circuit? If this is simply to power the CH/HW programmer and pump then this wont do any harm and is unlikely to overload the circuit, but I wouldn't consider it standard practice. It would have been better to wire into a socket ring main or a dedicated supply large enough to also support an electric immersion heater in the future.