How important is it to earth a exterior halogen floodlight?

Not many as you are unlikely to touch a LIT floodlight up a wall BUT if the thing does get a short to case on a damp wall it will trip your main RCD anyway.

cable is cheap. Why take the risk?

Being electrocuted at the top of the ladder, whilst changing the bulb? (Even if not electrocuted, the jolt may well kill you when you fall off.) Electrocuting a painter/windowcleaner/etc who happens to be working near it. ...

ONLY if its switched on, or it has a switch in the neutral AND its also faulty.

Doesn't adding a new external light where none existed before come under Part P?

There really is no point is most electrical earthing. After all, most appliances, switches, etc. don't become live and thereby threaten mortal coil shuffling to anyone. The regulations could be changed to save a fortune by only requiring the ones that are going to become live be earthed.

If it's got a metal case, the case can become live if it isn't earthed.

If it's this one:-

I was considering buying one today, but as my existing floodlights haven't been turned on since I moved in, I didn't bother. I don't even know whether they work.

Far too complicated for idiots.

Elfin Safety means earthing bits of plastic, bits of water pipe connected by plastic, and just about anything that moves.

When an accident happens, there's pretty well always more than one thing that's gone wrong. If you start by installing it wrongly, then that's one less additional thing that has to go wrong before it kills someone.

He hasn't yet asked if the switch goes in the live or neutral. Given the first question, he may well not think to ask even if he doesn't know.

Not if on the outside of a house. A circuit that needed to cross a garden to reach it would however be notifiable (should anyone actually care)

John Williamson wrote in news:ae5m0hF8cneU1 @mid.individual.net:

Yes, it has a metal case.

I have at lest two interior domestic table lamps that don't have an earth, despite the bulb holder (with integral switch), being made of bare metal! I always feel slightly uneasy when switching thosne lamps on. Perhaps they were made in days of yore when people were less cautious...

Thanks to all for the replies.

Bad idea, live to earth leakage is quite common on outdoor electrics. Add to the list being presented to a judge if someone has an accident

NT

In article , Al Shahadie writes

The general concept of electrical safety is that a single fault shouldn't expose a user to danger.

In the case of a metal cased lamp designated as requiring an earth (designed with an earth as a safety element), the insulation within the lamp is insufficient on its own to ensure the safety of the user in the event that it fails (a single fault). In this case the earth provides a safe path for fault current, blowing the fuse or tripping the overcurrent breaker for the circuit and leaving the lamp in a safe condition.

In the case of a lamp, metal cased or otherwise not designated as requiring an earth (designed to be safe without an earth), the insulation within the lamp will be to a far higher standard. It will either be made up of 2 separate layers[1], each of which would make the lamp safe on its own (in case one fails) or it will be tested to an especially high standard for 'reinforced' insulation which makes it reasonable to expect that it will not fail in service.

In both cases a single fault in insulation will leave the lamp safe.

If you fail to fit an earth to a lamp that has been designed to use it as a safety feature you are exposing anyone who might use that lamp in the future to significant risk should a single, relatively simple, fault occur.

Is the fitting Class I (earthed)

Stop being a cheapskate and go and buy the correct cable, otherwise a few years down the line, we will be reading "window cleaner electrocuted by DIY fitted lamp, all DIY electrical work to be outlawed".

En el artículo , polygonum escribió:

Which is exactly what they do.

No they don't. They require ones that COULD BECOME LIVE be earthed.

It seems quite feasible to me that the almost all things that could become live actually do not.

Obviously the time machine required to identify those which are actually going to become live adds to the costs...

Which it may be if the lamp has blown without you realising.

and especially so if its being switched by a PIR.

If a 2-core cable was already there and it was very difficult to replace with 3-core, ensure that the line is RCD or RCBO protected and there is an externally rated double pole isolation switch next to the light, so when changing a bulb the light is clearly off. It is still naughty but the best sort of naughtiness. The RCD or RCBO replace the protection of the earth to a large extent.

As you have 2-core on the table lamps with metal fitting, ensure the lighting circuit or sockets it is plugged into is RCD or RCB protected. And replace the metal fittings with plastic. Also have the switch in-line with the feed cable, so you are not touching any metal. An RCBO costs from £19 to £35, but a simple straight change with an mcb at the Consumer Unit. Fitting an RCD is more involved.

So, use 3-core and an RCD or RCB. And change the metal lamp fitting and fit an in-line switch to the lamps.