Double insulated down lights cpc

[Alextrician]

whats classes as the correct method of terminating an earth cable when you have double insulated fittings?

You can see on the picture I can’t get a wage inside nor a normal connector block it’s just too tight.

I have seen in the past the cpc being bent over and also snipped off which isn’t recommend just wanted to know the correct way of termination.

 

[Deleted member 26818]

As an amateur, I am really intrigued by this. I don't want to get into the semantics, just a practical solution. Let's suppose you have, say, 6 downlighters, loop in, loop out, one after another...no earth terminals on those fittings...if the "earth" isn't used/necessary, why not just "loop" it beside the light fitting, so ensuring there is a continuous cpc available if and when it may be required in the future? Containment isn't an issue if it's not being used, but is a question to be addressed if/when a class 1 fitting is substituted in the future?
Surely that is better than cutting it back/taping it to the outer of the t&e?
Pith helmet on...

It’s only really a problem when trying to comply with the Regs, or when the same switch and circuits feeds other non double insulated fittings.
The Regs say terminated at each fitting, and if the CPC is required further along, it needs to be continuous.

 

[pirate]

OK, so you might have a circuit that feeds both Class 1 and Class 2 fittings? So if you continue the cpc (by joining it outwith the Class 2 fittings)then it is "continuous" and can be utilised at the Class 1 fittings...in which case the cpc needs to be made continuous at each Class 2 fitting, and proper termination and containment might apply...

"terminated at each fitting"...beside each fitting?
within each fitting?
"in reasonable proximity to each fitting such that it may be readily utilised"?

Is it maybe just common sense to keep a cpc "handy" at all fittings, properly connected/terminated for use if required?

In practice, it's quite easy to use a JB that loops in/out all three wires, except the cpc is a straight through where no earth is needed, but I would have thought that mixing types would be unusual, but not extraordinary...
and I haven't seen it, being strictly amateur...

 

[Deleted member 26818]

To be honest, most of these small fittings are poorly designed when it comes to terminating.
PIRs are the same, especially when you’r trying to fit loop in, loop out and a feed to a fitting.
The old GU10s weren’t much better, a tiny enclosure often with only two terminals fixed to a bent piece of metal clipped into one of the springs.
Becomes a töss up whether it’s easier to terminate the loop in loop out into a choc box and spur some 2 core flex out to the fitting or waste time fitting the loop in loop out into the terminals on the fitting.
Have to make sure the chock box will fit through the hole for the fitting first.

 

[Ffoeguk]

Pirate is correct, the regulations are a guide. The skill is with the electrician. T&E is not the correct cable to connect any down lights.
In GU10 days it was temperature which pointed the way to the use of heat resistant flex from a JB to the light. The CPC should never be removed from the T&E cable, cut out or pulled back from the JB. It should always be terminated.
Makes me worry about the skill level of the electricians Great Britain is producing when this subject has spanned 7 pages, with people looking for ways not to do the job correctly. The CPC should be left local to and accessible for any future use. 526 Electrical Connections indicates the correct way to terminate the afore mentioned problem.
hope this helps
Electricity at work Act 1989 states:
integrity of referenced conductors
9. If a circuit conductor is connected to earth or to any other reference point, nothing which might reasonably be expected to give rise to danger by breaking the electrical continuity or introducing high impedance shall be placed in that conductor unless suitable precautions are taken to prevent that danger.

 

[snipersmith87]

It's protecting the cable.

The over current protective device protects the cable....the cpc protects us.

 

[Deleted member 26818]

Pirate is correct, the regulations are a guide. The skill is with the electrician. T&E is not the correct cable to connect any down lights.
In GU10 days it was temperature which pointed the way to the use of heat resistant flex from a JB to the light. The CPC should never be removed from the T&E cable, cut out or pulled back from the JB. It should always be terminated.
Makes me worry about the skill level of the electricians Great Britain is producing when this subject has spanned 7 pages, with people looking for ways not to do the job correctly. The CPC should be left local to and accessible for any future use. 526 Electrical Connections indicates the correct way to terminate the afore mentioned problem.
hope this helps
Electricity at work Act 1989 states:
integrity of referenced conductors
9. If a circuit conductor is connected to earth or to any other reference point, nothing which might reasonably be expected to give rise to danger by breaking the electrical continuity or introducing high impedance shall be placed in that conductor unless suitable precautions are taken to prevent that danger.

The particular fittings being discussed are 230V and designed for loop in loop out.
The pictures on Screwfix show 3 of the fittings looped together.
BS7671 requires us to terminate a CPC at each fitting, yet the fittings have no terminal for the CPC.
Not sure where you have obtained the information about T&E not being suitable for connecting to down lights?

In any event, can you explain how you in this instance, would follow manufacturer’s instructions, whilst also complying with the requirements of BS7671?

 

[Octopus]

Pirate is correct, the regulations are a guide. The skill is with the electrician. T&E is not the correct cable to connect any down lights

Sorry but have to disagree with that. There are downlights on the market specifically designed so twin and earth can , and should be used.

JCC and KSR are 2 examples

 

[Deleted account]

The over current protective device protects the cable....the cpc protects us.

My statement wasn't accurate so you are correct.

However my meaning was the cpc in the cable is there for protective reasons, to create an earth fault path in the event of penetration of the cable which would result in the tripping of the mcb or rcd.

Without a cpc the circuit would rely on a short circuit to trip the mcb. An earth fault could not occur so additional protection by rcd would not occur.

So yes the cpc in the cable is protecting us not the cable.

 

[Ffoeguk]

Alextrician asked
"whats classes as the correct method of terminating an earth cable when you have double insulated fittings?

You can see on the picture I can’t get a wage inside nor a normal connector block it’s just too tight.

I have seen in the past the cpc being bent over and also snipped off which isn’t recommend just wanted to know the correct way of termination."

Above is the original question to which my answer relates, it is not brand specific but suits all installations.
T&E is for fixed wiring, under certain limitations. Heat and sunlight are the 2 things that affect T&E the most, put your hand up if you would install external lighting with T&E clipped to an external wall.

spinlondon states:
BS7671 requires us to terminate a CPC at each fitting, yet the fittings have no terminal for the CPC.
412.2.3.2 states Except where regulation 412.1.2 applies, a circuit supplying one or more items of Class 2 equipment shall have a circuit protective conductor runto and terminated at each point in the wiring and at each accessory. It does not say in the accessory!!