Wiring LV lights

True - but, alternatively, you could still use T&E without connecting

But Owain seemed to be saying that it is a *requirement* - presumably on safety grounds - to have it connected at the supply end. I don't doubt that he is right, but am just curious to know what is the logic behind it. Just what sort of potential disaster does it prevent?

That would be silly. It makes life very difficult for no good reason. Its the stupid sort of thing that some trades people do to make life difficult for the DIYer.

Regs require all mains cables to have a CPC, I would envisage one reason being so that anywhere an accessory is connected it can be earthed if needed.

Ah, back in the halcyon days of red-and-black when Part P was just a tingle in John Prescott's surgical truss.

Owain

So, in a cable dedicated to a transformer for LV lighting, no immediate disaster is going to occur even if the cpc *isn't* connected.

Indeed. And I still have a reasonable supply of old-colour cable!

No, but what you should have done was connected the feed end normally, then sleeved and taped the other end so it could be used later if needed.

The regulati "In every installation which provides for protection against indirect contact by automatic disconnection of supply, a circuit protective conductor shall be run to and terminated at each point in the wiring and at each accessory except a lampholder having no exposed-conductive-parts and suspended from such a point."

Note the key words "and terminated". It is not acceptable to cut the CPC (earth wire) off flush with the end of the cable sheath. It must be connected to some form of terminal in order to be available for future use.

Reg. 471-09-02 makes it crystal clear that the above still applies where Class 2 ('double insulated') equipment is to be installed. There is an exception in 471-09-03 for special situations remaining under engineering supervision - this certainly could not be applied to a domestic installation.

Future-proofing, as already explained.

Replacement equipment or alterations or extensions to the installations being left unearthed because some idiot cut the wire off. (This used to happen a lot in the dim and distant...)

Right - I've just had a crawl in the attic to remind myself what I actually did 5 years ago - and it looks ok.

I have 2 transformers connected into a junction box with short (~ 1 metre)

That would also suggest my usual practice of leaving the CPC full length at the transformer end, but sliding a slightly longer bit of earth sleeving over it, and then folding it back on itself to keep the sleeving in place and the wire out of the way is technically not correct then since it is not terminated as such.

That's exactly what I do as well. What else are you expected to do? - maybe attach a floating one-way terminal block to the end or something? (Not that I've ever seen that done in any installation I've worked on, and my usual practice has been signed off without comment during Periodic Inspections...)

David

Hmm, no definition of "terminated" is provided. Is termination in a piece of sleeving acceptable? I've certainly done similar things myself where no earth or parking terminal was available, but termination into a single piece of choc-block or one end of an in-line crimp splice is regarded as better.

Would a single choc block hanging off the end of the ECC be considered better?