Extractor fans - is the double pole isolator switch mandatory?

[BigWallop]

The neutral is more likely to be at, or very very close to, the same potential as earth. So why should the switch need to be double pole?

[Stefek Zaba]

Letter-of-the-regs answer: because they're specifically exempted!

Why-we-don't-all-die answer: ES holders where the outer screw is all-metal are dinosaur objects - nothing that's been on general retail sale for domestic use has had the all-metal-outer-screw construction for

20+ years. The construction that's replaced it has a plastic or ceramic thread, with a spring contact some way down which makes contact with the ES blub's screw-in base. Arguably, the two contacts on such an ES holder are a little less likely to be touched than the two pins of the British Bayonet.

Yes, halide; yes, stage lighting fittings. I did say "domestic use".

And again in th'domestic case, most people who want to get on with life switch off before changing a bulb, and avoid poking their fingers in anyway; and are rarely in low-resistance contact with earth should they make inadverdent contact anyway.

But hey, if you want to get double-pole switching for lighting circuits written into 17th Edn Regs, campaign away...

[Derek *]

Following up to last week's thread.

A "Bathroom Fan" is not a "Fixed Electric Motor".

It strikes me that I've never seen a bathroom fan with it's own isolator in any of the (what seems like millions of) hotel/lodge bathrooms I've used, which almost universally have a fan controlled via a run on timer operating off the light switch. In fact I've never seen such a fan with a dedicated isolator switch at all, an occasional fused spur, possibly.

Clearly this regulation was intended to apply to bigger, more powerful electric motors which constitute a seperate installation in themselves, with the intention of ensuring it is possible to reliably isolate it for maintenance of the motor and the machinery it drives, or in an emergency.

There is a difference between an 8 watt motor inside a "loovent" and a 5 horsepower "Fixed Electric Motor" driving a workshop full of machine tools through shafting and belting.

Or am I wrong?

DG

[BigWallop]

You're wrong.

[Lurch]

On Mon, 03 Jan 2005 15:13:04 +0000, Derek * strung together this:

What is it then?

Right then, several reasons why this could be.

The wiring could be wrong. The isolator could be hidden from direct view to stop people turning it off. The isolator could be a lockable one in a remote location. The fan could be fitted in a void somewhere, in which case it would have an isolator local to it.

No, when you say clearly you mean you have no idea so you're making it up as you go along.

There is in physicsl size, but not in the way the isolator rules apply to them as they are bioth fixed electric motors.

Yes, you're guessing and assuming. You haven't a clue so please please please don't touch anything electrical in the future.