Extractor Fan wiring

[beontheweb]

Hi,

I have just moved house and in the kitchen there is an existing electric Xpelair extractor fan vented through the wall to outside. It looks like it is wired from an existing 13amp socket via an isolating switch using 1.0mm twin and earth flex (pinned to the wall surface).
I would like to confirm if this complies with current wiring regulations?
For example, is 1.0mm flex enough or should it be 1.5mm twin and earth?

Any advice welcome.
Thanks.

 

[JohnD]

1mm is OK. There should be a 3A fuse cartidge in the plug. 5A would do.

It is a bit poor to use a plug and flex for a fixed appliance, an FCU with flex outlet would be better.

It would be even more elegant to use an FCU at worktop height with a cable chased into the wall running vertically to a flex outlet adjacent to the fan.

 

[beontheweb]

Thanks for the reply JohnD.

Just to clarify, there is no 13A plug involved. The power is sourced from the back of a 13A socket (short length of flex out the edge of the facia!). This short length of flex then enters a switched FCU (don't know what the fuse in there is rated yet!). Another length of flex then leaves the FCU and is pinned around a window to the Extractor Fan itself.

Your suggestion of an FCU at worktop height and a flex outlet adjacent to the fan sounds very tidy. Bearing that in mind, I would like to do away with the cabling over the wall surface, but want to avoid too much work channeling the cable in the wall. I can gain access to the void behind some existing coving. Would there be any regulation issues running a new cable behind the coving and then channeling down the wall to the new flex outlet / fan?

Thanks.

 

[securespark]

What is the protective device?

 

[beontheweb]

Hi Securespark.

What is the protective device?

Forgive my ignorance, but what do you mean by this?
Would that not be the switched FCU fitted between the 13A socket connection and the fan itself?

 

[Steve]

Think he means the circuit protective device, at the fusebox / consumer unit. What is the rating of the fuse / MCB and which is it?

 

[beontheweb]

Aha, in that case, the socket supplying the circuit in question is on the downstairs ring main which I believe is protected by a standard 30A fuse wire in the main fusebox.

 

[pcboffinuk]

Would there be any regulation issues running a new cable behind the coving and then channeling down the wall to the new flex outlet / fan?
.

You are allowed to run cable in 'safe' zones without additional protection, and one of those safe zones is along the top of a wall (although some people don't like that method)

//wiki.diynot.com/electrics:installation_techniques:route has more information on those routes.

From what you say, the flex connecting the 13A socket to the Switched FCU is undersized - by the regs it should be 2.5mm2, the same as the ring main. From the FCU it can be smaller, depending of course on what fuse is fitted.

I should add for completeness that since this is in a kitchen, rerunning cable would be notifiable to building control under Part P - if you were just replacing the cable from socket to FCU it would technically still be notifiable I think, but I wouldn't let that stop you doing it.

Gavin