Class 2 light's

[dokkan1080]

would a class 2 light fed from a flex off of a hager klik Marshall box need a 2 core and earth flex or would a just a 2 core flex be okay

on an rcbo

 

[Mikegh]

The other thread seems to have disappeared

I was arguing that you can in theory as fixed wiring requires a CPC at points while appliances and accessories can be wired in 2-core

Luminaires I would also say the CPC may be brought to a junction in the case of selv downlights and a robus trafo with 2-core lead connected


Other side of the argument is they're 3 and 4 pin plugs and the earth should be brought to luminaire as it may be changed later to a class1 type

 

[westward10]

Nine times out if ten you will get the ready made plug and cord which will be three core to save time. For a fitting which doesn't need three core and has no facility to connect the earth just use another lighting connector, three core to one side two core to the other.

 

[dokkan1080]

Nine times out if ten you will get the ready made plug and cord which will be three core to save time. For a fitting which doesn't need three core and has no facility to connect the earth just use another lighting connector, three core to one side two core to the other.

Thats how it would be ideally but is 2 core okay

 

[dokkan1080]

The other thread seems to have disappeared

I was arguing that you can in theory as fixed wiring requires a CPC at points while appliances and accessories can be wired in 2-core

Luminaires I would also say the CPC may be brought to a junction in the case of selv downlights and a robus trafo with 2-core lead connected


Other side of the argument is they're 3 and 4 pin plugs and the earth should be brought to luminaire as it may be changed later to a class1 type

But with no earth would it be compliant?

 

[westward10]

Thats how it would be ideally but is 2 core okay

I don't see why not.

 

[timhoward]

As it's ok to have 2 core flex leaving a ceiling rose to a suspended BC holder I don't see what the difference is with a class II fitting.

 

[littlespark]

I wondered where the other thread went….

as I mentioned on the other one, you wouldn’t wire downlights with only two core, you’de take an earth there too, even if not used.

I believe standard BC pendants are a special case, all other luminaries should have an earth in the flex… (IMO)

 

[timhoward]

I believe standard BC pendants are a special case, all other luminaries should have an earth in the flex… (IMO)

I know BC pendants are a special case regarding Basic Protection, but can't recall any other exceptions.

all other luminaries should have an earth in the flex… (IMO)

I generally agree with you on most things (!) but do wonder about this.
As you can have a 3 pin plug with 2 core flex in it for a class II appliance, and could could potentially connect a class II appliance to an FCU with 2 core flex, I'm not immediately sure why luminaires should be any different.
I encounter this quite a lot with the LED grid ceiling panel panels with a transformer - they have no room to terminate an earth beyond the clamp, or loop in and out. The neatest approach I've found is to use a Quikwire flex connector on the in and out cables to maintain the CPC, and a short 2 core flex to the transformer which is marked class II and the output is SELV. For reasons above and fact it was SELV I reasoned this was ok.

I'd be genuinely interested if anyone's aware of specific regs on this kind of thing.

 

[littlespark]

The only thing different between this and a table lamp with 2 core flex would be the fused plug, I suppose… but then it’s an appliance, covered by it’s own rules.

 

[timhoward]

BTW I've had a nice glass of Oban and a quick scan through the regs.
The closest I can get to anything relevant is the general fault protection section:
411.3.1.1 ... A cpc shall be run to and terminated at each point in wiring and at each accessory except a lampholder having no exposed-conductive parts and suspended from such a point.

"point in wiring" is in section 2 and says "a termination of fixed wiring intended for the connection of current using equipment"

It's not quite an exact fit, but pretty close if the Quickwire is the "point in wiring", and the way downlighters are fitted by a lot of cowboys they end up suspended half the time!

 

[Mikegh]

That would seem to me to suggest 3-core is necessary

Suspended to me means hanging in free air

I dunno

 

[timhoward]

Yeah, I know what you mean. I honestly have no idea how to do anything else for something like this though. No chance of safely terminating a 3rd core in there!


(this is more an example of the wiring space than a particular product I would choose to fit btw!)

 

[Dartlec]

It's something that has cropped up before for me with the LAP cheapo downlights (which actually aren't awful).

https://media.NoLinkingToThis/is/image//ae235?src=ae235/3046V_P&$prodImageMedium$

They have two terminals for L and N, but no provision for earth - so you can be sure that most people installing them will either cut it short or think they should use 2 core...

The 'installation' image even suggests as much

https://media.NoLinkingToThis/is/image//ae235?src=ae235/3046V_A1&$prodImageMedium$
and last time I looked at the instructions for one there was nothing about ensuring any existing earth is linked separately. I used Wago lite boxes for the feed cable with earth, and then short 2 core flex to the light last time I installed any - and the NICEIC assessor had no issues with it.

I think if the quick fit connector has an earth terminal, then 3 core should be run to it, and I'd likely do it anyway to each junction box at least, because the price difference is so slight and there is always the chance of a change of fitting to Class 1 in the future.

Whether that is a strict requirement under the Regs is another matter..

 

[Mikegh]

Nine times out if ten you will get the ready made plug and cord which will be three core to save time. For a fitting which doesn't need three core and has no facility to connect the earth just use another lighting connector, three core to one side two core to the other.

Something like that seems a.good compromise

Bring the 3-core as close as possible to the accessory if not able to connect

In the example of the transformer you'll have a cable joint with CPC which will drop-down the hole so is present at the accessory in reality