Electric shower to power shower wiring

[TheKeymeister]

At some point (by previous owners) the shower in my ensuite has been changed from an electric heated shower (where it heats its own water) to a pumped power shower (with hot and cold feeds). I suspect it was wired up by the plumber as they've done away with the existing 6mm feed from the CU on its own 32a MCB, and instead put a 3a FCU in the loft connected to the nearest lighting circuit.

I can't imagine that complies with anything at all, especially as there is no local isolation, so I want to put it right. I'm thinking of disconnecting the feed to the FCU in the loft and connecting it to the outgoing side of the now defunct shower switch. Is there a better way of doing this? I can't see that there's such a thing as a fused shower switch which would have been perfect for the job.

It would look something like this :-

32a breaker (Shower) => Shower pull switch => 3a FCU in loft => Shower

Thanks in advance

 

[deadshort]

What you propose to do is fine, as long as you have the 3a fuse fitted in the FCU. Is the supply RCD protected ? it should be.
If not, you can install a rcd FCU.

Regards,

DS

 

[EFLImpudence]

It's fine as it is.

A power shower is just a small pump.
You have local isolation at the FCU.

 

[TheKeymeister]

Yep, its an old Wylex single RCD board with the early NSB breakers with coloured switches. Just thought of one potential problem, I suppose the cable between the shower switch and FCU would have to be 6mm, and I'm not sure if I've got any...hopefully the old feed to the old shower is still there for me to scavenge a bit.

Does it count as local isolation when it's in the loft which isn't easily accessible? And is it acceptable to be fed off a lighting circuit?

 

[EFLImpudence]

Does it count as local isolation when it's in the loft which isn't easily accessible?

Yes. You can switch it off should the pump become faulty.

And is it acceptable to be fed off a lighting circuit?

Yes. Alter the CU label then it will be a lighting and pump circuit.

 

[Taylortwocities]

You could dispense with the shower switch altogether. Most shower pumps are permanently powered in any event. The FCU can provide isolation if needed.

 

[winston1]

But FCUs are not used or needed on lighting circuits. If you want isolation use a DP switch.

 

[Taylortwocities]

I was referring to the OP retaining the old shower feed. Not using the lighting circuit.