Shaver Socket from a Ring Final

[Marcus Vaughan]

Hi All,

A customer has asked for a shaver socket to be installed in his bathroom.

The only issue is that there is no lighting circuit available (loft conversion above and no access to the eaves).

His idea was to come off a socket in a bedroom on the other side of a stud wall to the proposed location.

I'm assuming its a ring final.

My first thought was - yeah - but I'll have to put a fused spur.

Then I thought - wait a minute - shaver sockets are 230 volts anyway - and have their own inbuilt thermistor to trip at only 200mA.

I can't see any regulation or design problem that enforces the need for the fused spur - so I could just run a 2.5mm or even a 1.5mm to it? Its not a fixed load as such, it can't be overloaded.....

Bad practice?
I am wondering what others would do?

I suggested a mirror light with integrated shaver scocket - which are SELV - now that I would fuse down because the light is a fixed load...

 

[Rpa07]

By an MCB 'or alternatively' an FCU so the MI does give you the assessed choice!

Interesting question, MK has a pdf of the MIs here, they look a bit dated and generic (isolated/non isolated, red-black wires) but presumably they're still valid. It says this about the mains supply..

5. Isolated shaver supply units should be connected to a mains supply protected by an MCB or fuse of 10 amps maximum rating, such as lighting circuit, or alternatively to a fused connection unit that complies with BS1363: Part 4 supplied from a ring circuit.

So it looks like a fused spur is required to meet the 10A protection spec.

But in this case as MV is coming from an RFC then FCU with max 10amp fuse it is.

 

[Shoei]

By an MCB 'or alternatively' an FCU so the MI does give you the assessed choice!

True, I was referring to @Marcus Vaughan s application with a 32A protected ring.

Edit:
That pdf link I posted does look out of date so I had another look at the MK site, this one seems more current, a generic instruction set (Wiring Devices Technical) for a range of MK Logic stuff include the Logic+ shaver socket. It doesn't say anything about supply protection but does mention internal protection for the transformer.

@Marcus Vaughan , does that one on the van still have its MIs? Maybe they improved protection on later units to avoid the need for an FCU.

 

[Marcus Vaughan]

@Marcus Vaughan , does that one on the van still have its MIs? Maybe they improved protection on later units to avoid the need for an FCU.[/QUOTE]

I just had a look, pulled it out of the box, but no instructions with it?

 

[DefyG]

If you had discovered that doing an EICR what would you have thought? ……..
Its a spur off a ring circuit so therefore ok? The safety isolating transformer cannot supply more than its design current!

Ive come across this before when doing a bathroom refurb some years back and initial thoughts were that it is wrong but couldn't find anything in the regs to support that.

 

[Marcus Vaughan]

If you had discovered that doing an EICR what would you have thought? ……..
Its a spur off a ring circuit so therefore ok? The safety isolating transformer cannot supply more than its design current!

Good question. Earlier I said it would be a no-code but now I'm leaning towards a C3 - because of the replies above mentioning appendix 15 and those manufacturing instructions.

Ive come across this before when doing a bathroom refurb some years back and initial thoughts were that it is wrong but couldn't find anything in the regs to support that.

I think they'll be a lot of examples of it - but I cannot see any real risk with the set-up.

Does not mean I'm going to do it though - I am going to fuse it down. To ambiguous an issue not to.

 

[Shoei]

I think they'll be a lot of examples of it - but I cannot see any real risk with the set-up.

Does not mean I'm going to do it though - I am going to fuse it down. To ambiguous an issue not to.

Good call, the MK sockets have internal protection but it's to protect the transformer from overload, it doesn't help if the transformer fails.

If a fault develops on the transformer primary and it's connected direct to the ring then there's enough power to set it alight without tripping the breaker. MK have mitigated the hazard by specifying max 10A protection.

 

[Dave OCD]

The thing is if you fit a FCU you can then use 1mm to the shaver socket so much less faff.

 

[Marcus Vaughan]

The thing is if you fit a FCU you can then use 1mm to the shaver socket so much less faff.

Yep. It’s got to be the way to go.