Spa Bath installation and bonding*Newbie question*

[Gadfium]

OK, here goes (and apologies if this is incorrect as i am a newb!)

i am finishing off an extension that was added to my house last year. The extension contains an ensuite bathroom, into which I am fitting a spa bath. The bathroom will also have a power shower (over the bath)...the pump for this is under the hot tank in a sperate airing cupboard.

The sparky that did the electrics ran a cable from a downstairs ring main to supply the spa bath. I am going to fit a switched fused spur with a 30A RCD (both mounted into the plasterboard bedroom/bathroom wall- facing into the bedroom). The flex from the bath pump will terminate in a waterproof junction box under the bath, then to the RCD. I have also bonded the bath & shower pipes to the bath legs, sink hot & cold pipes and the radiator, using 10mm cable (should be 4mm......but should be no harm!).

Does this sound OK??? Do I run the new bonded earth to the earth pole in the RCD (or junction box), or does it need to run back to the existing airing cupboard, where the old pipes are bonded to the immersion earth point?

Also, will i need to install a ceiling pull switch for the shower pump (I am going to fit an RCD off an existing spur to power the pump)??

I hope I have given enough info....if not please let me know.

[Gadfium]

Anyone????? Any help/advice much appreciated

[ban-all-sheds]

Gadfium wrote:

Do I run the new bonded earth to the earth pole in the RCD (or junction box), or does it need to run back to the existing airing cupboard, where the old pipes are bonded to the immersion earth point?

Both.

Quote:

Also, will i need to install a ceiling pull switch for the shower pump (I am going to fit an RCD off an existing spur to power the pump)??

The shower pump should have a means of local isolation, so you do need a switch. Whether it should be a pull-switch depends on where you want it...

Also, the existing spur - is it a fused one itself?

And why have you got all these extra RCDs if these are spurs off the downstairs ring - surely that's already RCD protected?

[Gadfium]

Thanks for the reply.

Quote:

The shower pump should have a means of local isolation, so you do need a switch

I had intended to put a switched spur to the shower pump off a nearby socket (or off the immersion heater point....would that be better??). I take it that there will then be no need to have a pull switch in the bathroom???

Quote:

And why have you got all these extra RCDs if these are spurs off the downstairs ring

I don't think so. The main CU doesn't have RCDs...fuses only (replacing it is a job for another day). It had assumed that as it was connecting to a bath that a dedicated RCD would be best for safety reasons.

Quote:

Also, the existing spur - is it a fused one itself?

I believe so.....

[ban-all-sheds]

Gadfium wrote:

I had intended to put a switched spur to the shower pump off a nearby socket (or off the immersion heater point....would that be better??). I take it that there will then be no need to have a pull switch in the bathroom???

A switched FCU will be fine for isolation purposes, but I don't think I've ever seen a switched RCD FCU. As for which circuit, there are those who deprecate the use of "immersion heater circuits" for additional purposes, but I maintain that a circuit is a circuit, and provided that the cable and the fuse/MCB are rated in accordance with the expected load then there's nothing wrong with this.

Quote:

The main CU doesn't have RCDs...fuses only (replacing it is a job for another day). It had assumed that as it was connecting to a bath that a dedicated RCD would be best for safety reasons.

Oh yes.

Quote:

Quote: Also, the existing spur - is it a fused one itself? I believe so.....

Good-oh.

[Gadfium]

ban-all-sheds wrote:

I don't think I've ever seen a switched RCD FCU.

I have put in a switched fused unit, then the RCD.....probably belt and braces, but it does allow me to isolate the sub-circuit

ban-all-sheds wrote:

As for which circuit, there are those who deprecate the use of "immersion heater circuits" for additional purposes, but I maintain that a circuit is a circuit,

Hmmm.... on reflection, I will probably not use the immersion circuit, for the simple reason that acccess is awkward. There is a 13A socket beside the airing cupboard where the shower pump now lives, and I will probably spur off this and stick a RCD in to power the shower pump. Would this be OK????

[theshogun]

You could use a combined FCU RCD less conections to do av from screwfix

[Gadfium]

I was on Screfix today, and all i could get was http://www.screwfix.com/app/sfd/cat/pro.jsp?ts=13371&id=14770

I am sure that I did see the switched FCU with RCD in the past tho.....

[theshogun]

thats the one rcd fcu 13 amp