Wiring extractor fan into outside light.

[EddieJT]

I have a dedicated radial circuit from my CU that feeds 2 outside PIR lights. The outside cable to this conveniently passes the position on the outside wall where I intend to fit an extractor fan for my bathroom. Can the t&e cable going to the outside light be spurred off for a proximity sensor extractor fan?

The fan has no earth, and instructions say nothing about needing a switch.

 

[PrenticeBoyofDerry]

Have you a link to the extractor fan, just make sure it does not require a switch and perm line, for overrun. If it does you cannot use a twin and earth.

 

[Iggifer]

PIR fans usually just require a Perm L and N.

Go for a decent brand though, we fitted some last week from a major electrical wholesaler, and the PIR module was glued to the cover. This meant that whilst fitting, the lid was hanging by the PIR cables. Poor design. One fresh out of the box had already had the PIR come off.

 

[PrenticeBoyofDerry]

The fan has no earth, and instructions say nothing about needing a switch.

The wiring regulation will suggest the requirement for switching/isolation and recommend a cpc being present.

 

[EddieJT]

Thanks guys.

The fan and outside light are on their own circuit which can be independently switched off at CU. Is this not sufficient isolation?

If not, would putting a 3 pole switch in series do the job? Should it be fused?

 

[bernardgreen]

can be independently switched off at CU. Is this not sufficient isolation?

Isolation for outside lighting should have the both Live and Neutral isolated. Isolating the Live and not isolating the Neutral can still trip the RCD if there is a fault in the lighting that creates leakage to Ground or Earth. Rain water in the lamps is a common cause of this

 

[securespark]

Go for a decent brand though, we fitted some last week from a major electrical wholesaler...

5h1tty?

 

[Iggifer]

5h1tty?

Maybe

 

[EFLImpudence]

The fan and outside light are on their own circuit which can be independently switched off at CU. Is this not sufficient isolation?

As far as the regulations are concerned - Yes.

Local isolation is not a requirement; just a good idea.

 

[EFLImpudence]

would putting a 3 pole switch in series do the job?

You must not switch the CPC(earth wire)

Should it be fused?

Not necessary assuming it has the appropriate MCB already.

 

[EddieJT]

Very helpful. Thank all.

 

[PrenticeBoyofDerry]

You also need to be aware of the methods of jointing that is allowed, if the joint is going to be inaccessible when completed.
Then there is the permitted safe cable routes, and the added protection via RCD if the location requires one, or if cables are buried in walls less than 50mm without mechanical protection.
Then with regards of chases for buried cables, they must comply to the structural depths allowed.
And then whether the work is deemed notifiable to building controls, if work is undertaken in the bathroom zones.