Share isolation switch - allowed?

[elmoputney]

Hey folks, I need some guidance, searched but could not find any answers.

In my bathroom I currently have a 45A DP isolation switch for the electric shower, I'm going pumped (under bath) so was going to use the existing switch and wiring for the pump but fused down to a suitable value.

At the same time I would like to fit a towel rail electric element, 2 questions:

1/ I assume I need to have a DP isolation for the towel rail element even if I use this:

http://www.traderadiators.com/acatalog/Wall Plate Towel Rail.pdf


2/ To avoid another pullcord or external switch I don't suppose its permissible to share the 45A DP ex shower - now shower pump isolation switch? between both the pump and the towel rad?

Thanks all.

 

[EFLImpudence]

In my bathroom I currently have a 45A DP isolation switch for the electric shower, I'm going pumped (under bath) so was going to use the existing switch and wiring for the pump but fused down to a suitable value.

Yes but a bit naff.

At the same time I would like to fit a towel rail electric element, 2 questions:
1/ I assume I need to have a DP isolation for the towel rail element even if I use this:

No, single (FCU) will suffice although double would be better.

2/ To avoid another pullcord or external switch I don't suppose its permissible to share the 45A DP ex shower - now shower pump isolation switch? between both the pump and the towel rad?

I don't see why not, electrically. I just don't like the idea of using the switch.
Is there not a way to do it properly - loft above or airing cupboard or spur from Ring nearby?

You must install RCD protection if not already in place.
Also it is notifiable work and should be properly tested before energising.

 

[elmoputney]

Thanks for responding.
I have a loft above but assumed isolation would need to be "close" i.e. inside the room (zone3) or outside above door or similar, would individual isolation in the loft one for pump one for rad be allowed?


It's all already on a 30ma RCD, so I'm ok there, no ring on any adjacent walls and only lighting circuit (and shower circuit) in the loft which is whats driven me down this solution.

I just don't like the idea of using the switch.

Please explain why? Just because the big 45A switch is ugly as?

Also it is notifiable work and should be properly tested before energising.

Understood, will be seeking help on that from a sparky

 

[riveralt]

Also it is notifiable work and should be properly tested before energising.

Understood, will be seeking help on that from a sparky

Not sure you do. If you intend you use an electrician who is a member of a competent person scheme then he should be involved before and during the installation - he cannot just come along and test your installation at the end and give you a certificate.
If you intend to do the work yourself then you should be speaking to your Local Authority Building Control Office.

BTW Zone 3 does not exist anymore.

 

[EFLImpudence]

I have a loft above but assumed isolation would need to be "close" i.e. inside the room (zone3) or outside above door or similar,

No.
As has been mentioned - now only zone 1, zone 2 and 'outside zones'.

would individual isolation in the loft one for pump one for rad be allowed?

Yes, it is to isolate for maintenance.
You can use the shower circuit - fused down, as you said.
All out of sight.

I just don't like the idea of using the switch.

Please explain why? Just because the big 45A switch is ugly as?

Yes. Unavoidable for showers.

 

[JohnW2]

1/ I assume I need to have a DP isolation for the towel rail element even if I use this:

No, single (FCU) will suffice although double would be better.

Do SP switched FCUs actually exist? (real question, not rhetorical).

Kind Regards, John.

 

[securespark]

I think some early ones used to be. But AFAICT, all FCU's now are DP.

Unless there are some cheap Chinese imports, I shall stand corrected.

 

[JohnW2]

I think some early ones used to be. But AFAICT, all FCU's now are DP.

That was certainly what I thought.

Kind Regards, John.

 

[EFLImpudence]

1/ I assume I need to have a DP isolation for the towel rail element even if I use this:

No, single (FCU) will suffice although double would be better.

Do SP switched FCUs actually exist? (real question, not rhetorical).

Who said switched?

 

[JohnW2]

Who said switched?

Oh, I see

Kind Regards, John.

 

[EFLImpudence]

In answer to your question I am sure they do exist - just one neutral terminal.

Whether the ones I've encountered were all old I am not sure.

Yet, still, in advertisements for SFCUs some mention DP and some do not so I would assume the ones that do not are not.

Although I'm not certain, I will have a look tomorrow.

 

[JohnW2]

In answer to your question I am sure they do exist - just one neutral terminal. Whether the ones I've encountered were all old I am not sure.

I certainly don't recall having seen one of those.

Yet, still, in advertisements for SFCUs some mention DP and some do not so I would assume the ones that do not are not.

That's certainly not true - many of the current advertisments don't mention DP switching, and nor are a lot of the roducts marked 'DP', so I always test any I buy or acquire (unless they have DP marked on them) - and I can't recall (certainly not for a good few years - I wouldn't trust my memory back 'for ever!) ever having come across one which isn't DP switched.

Kind Regards, John.