GU10 downlighters - Class II?

[SolarCity]

This has probably been covered before but I can't find any info on it. Can anyone tell me how some GU10 downlights can be declared class II by their manufacturer when their general build appears to suggest they should be earthed?

 

[Wayne Watts]

Class II insulation is just unearthed metal separated from live parts by reinforced insulation or supplementry insulation. there are various ways to achive it but basically the metalwork is not earth potential and not likely to become live under a fault condition.
The IEE code of pratice for in service inspection and testing (used for PAT guidance) has some useful info on this too!

 

[SolarCity]

That may be so but some GU10 fittings, in my opinion, have every chance of becoming live under fault condition.

 

[Top Cat]

Thought about that myself. Just because the cables are going through a grommet, does'nt mean the grommet could'nt come adrift after several lamp changes.

 

[Farmelectrics]

how could the metal become live the ones i fit are class 2 just 2 cables going into porcelane lamp holder seprate from crome surround

 

[Wayne Watts]

I appreciate that as electricians we have these opitions of what if and how but the product type/spec will vary by manufacturer. regs require us to follow thier instructions, not our opinions. If the product is type test class II even if we think it should be earthed, we would be causing more danger trying to earth it! Just accept the manufacture info as a given!

 

[jumpin jax]

I have also fitted somme 'class 2' downlights where the cables are clearly not double insulated, how does that work?

 

[Wayne Watts]

The wiring system should always be wired with CPU (earth wire) to facilitate any existing or future accessories that may require earthing. BS 7671 requirements for double insulated circuits would usually be in more specialised installations / areas. Simply ensure that the earth wires are connected together to maintain the CPU throught the installation. Some manufaturers supply a "spare" terminal for this.

 

[SolarCity]

I've seen GU10 fittings labelled as class II where the cable passes through the metalwork of the fitting - now I know the cables will be rated to do so but surely the risk that these cables will degrade after years of heating a cooling could compromise this protection?

 

[Adam W]

Class 2 equipment is constructed using double or reinforced insulation therefore can still be class 2 even if there doesn't appear to be 2 layers of insulation.
Equipment with metallic casing can also be class 2 if there is insulation between the live parts and metallic outer parts.

 

[Wayne Watts]

There is always insulation between the metalwork and live parts! At least there is in my installations! Ouch! I think post #2 covered that a week ago!
I think I'm going onto a plumbers forum to wind some of them up! Lol.

 

[Adam W]

There is always insulation between the metalwork and live parts! At least there is in my installations! Ouch! I think post #2 covered that a week ago!
I think I'm going onto a plumbers forum to wind some of them up! Lol.

Yes but it isn't always double or reinforced insulation, which is what we're talking about here.

 

[Wayne Watts]

This really does make me laugh. Hello! That's what I said in the second thread! I was just being funny about your previous comment! The whole point was regarding the manufaturers and how they could produce a class II product that looked like it should be earthed due to the exposed metalwork! I'm bored of this thread now!