Metal Class 2 Wall Lights.

ietmgreen: 
 

broadgage: 
 

 

In doubtful cases I would consider adding an earth connection if reasonably practical. I appreciate that some people are opposed to so doing, and state that adding an earth is “altering the design” or “voiding the CE marking”

 

Are there any real technical disadvantages to adding an earth connection?

Not so far as I am aware in the case of a light fitting. Adding an earth to complex equipment might have undesirable results WRT earth loops, data corruption, or interference with audio or video signals. But fine for a light fitting. 

wallywombat: 
 

ietmgreen: 
 

If the light switch is off, where is the voltage providing the fatal shock.???

That's why I put “know” in italics - because the householder is convinced that the light switch is off, but with a dead/missing bulb and no test equipment, it's easy to get it wrong - especially with 2-way switching. Or someone else switches it on right after the householder checks that it's off.

OK. Your italics were too subtle for me.

Are there any real technical disadvantages to adding an earth connection?

Sometimes Class II fittings have a specific advantage over earthed ones - e.g. where the fitting is outside the equipotential zone, or were normal dry skin conditions really don't apply (e.g. lights for zone 1 of swimming pools) - so in such (rare) cases there would be a disadvantage. Normally though, where Class I would be acceptable anyway, it unlikely to make any difference I would have thought. 

   - Andy.

Chris Pearson: 
 

Zoomy, you have mentioned that the light fittings are chrome, but what is the chrome plated on to?

Steel I reckon Chris.

Z.

Zoomup: 
 

Chris Pearson: 
Zoomy, you have mentioned that the light fittings are chrome, but what is the chrome plated on to?

Steel I reckon Chris.

Thank you. I asked because the only way that I could imagine a Class II device was chromed plastic.

the only way that I could imagine a Class II device was chromed plastic.

Quite a few steel framed appliances are class II - I've got an an anglepoise lamp and a stainless steel cooker hood that both are. As long as there's reliable double or reinforced insulation between the live conductors and the metalwork it should be fine.

    - Andy.

AJJewsbury: 
 

the only way that I could imagine a Class II device was chromed plastic.

Quite a few steel framed appliances are class II - I've got an an anglepoise lamp and a stainless steel cooker hood that both are. As long as there's reliable double or reinforced insulation between the live conductors and the metalwork it should be fine.

    - Andy.

The wall lights have no double insulation or reinforced insulation in the circular base. These lights are exposed conductive parts containing live single insulated wires using a normal nylon choc block, as found not even covered by electrical insulation tape.

Why do we earth steel conduit containing single insulated wires? Or steel trunking and other metal enclosures with the same single insulated wires? This situation is similar.

I will condemn this installation because of the requirements of 411.3.1.1 and 411.3.4. It is dangerous.

Z.

Well, in much of the world the conduit or trunking would only be earthed when serving as the main CPC.  However, in our double fault to danger world,  I agree, we should earth it, and perhaps these lights should be too, or the choc block sleeved. 

It is only potentially dangerous, in that a single fault as you describe,  could expose a dangerous voltage without relief from ADS,  rather than dangerous now, which would be if it was actually live.

Some makers of lights seem to make both class 1 and class 2 fittings on the same production line, and the only difference is the sticker, and if there is a screw or hole for an earth lug or not, I'd not read too much into it.

Mike.