Why do people twist CPC's?

I like “screwit” type connectors, they are very effective, insulated, and safe. I have never found one which did not make a positive connection unlike choc-blocks, or other things. In the US they are pretty much the only connectors used anywhere. This technique shown here is pretty horrible, but then so are a lot of jobs by the rough end of the industry.

davezawadi (David Stone): 
 

I like “screwit” type connectors, they are very effective, insulated, and safe. I have never found one which did not make a positive connection unlike choc-blocks, or other things. In the US they are pretty much the only connectors used anywhere. This technique shown here is pretty horrible, but then so are a lot of jobs by the rough end of the industry.

I have never had any problems with choc blocks. They have two screws and both can be used if conductors are pushed right through the body. Also it is reassuring to feel the tightness of the screws which indicate the security of the termination. Personally I like to see the final result. With other methods the result is hidden and unknown.

Z.

It takes two of them to do this??????? 

More like Tom & Gerry! 

I Around twenty years ago I was sat in a classroom at Kidderminster College on  Thursday evening after work attending an electrical training course.

The lecturer was running through ring final circuit testing in particular the continuity testing. On the rolling blackboard he chalked up a table of test results.

Having taken end to end continuity readings the ends of the circuit had been interconnected to create the big ring for testing and sockets tested, so at some sockets the reading was higher than others, but at one of them instead of a numerical test result it said “TPFO”.

I had to stop him and get him to explain it as I didn’t get it straight off after a long day at work, driving and sitting through half a lecture.

So we had a discussion about the cause and effect of “TPFO” , also how and why it’s best avoided.

Over to you ?‍?

“TPFO” Twisted Pair Fell Out, so you got good end to end readings on the socket ring circuit, but it failed testing at the socket.

going back those twenty years I remember it had been a long day and I replied “I thought there’s only twisted pair telephone cable, not twin and earth “ the lecturer announced it was time for a break and coffee then we would discuss it afterwards.

Twisting CPCs together was already an out dated idea twenty years ago and “is not encouraged because it makes fault finding and testing more difficult, also there’s effectively only one CPC rather than two increasing the risk of failpure“.

Since then most manufacturers have introduced double earthing connections on socket and other fittings as “Hi integrity earthing“ with the expectation that the CPCs will be connected separately to each of the two earth terminals to create Hi Integrity Earthing within the ring circuit inline with the requirements of the Wiring Regulations.

Back over to you. 

Sparkingchip: 
 

“TPFO” Twisted Pair Fell Out, so you got good end to end readings on the socket ring circuit, but it failed testing at the socket.

going back those twenty years I remember it had been a long day and I replied “I thought there’s only twisted pair telephone cable, not twin and earth “ the lecturer announced it was time for a break and coffee then we would discuss it afterwards.

Twisting CPCs together was already an out dated idea twenty years ago and “is not encouraged because it makes fault finding and testing more difficult, also there’s effectively only one CPC rather than two increasing the risk of failpure“.

Since then most manufacturers have introduced double earthing connections on socket and other fittings as “Hi integrity earthing“ with the expectation that the CPCs will be connected separately to each of the two earth terminals to create Hi Integrity Earthing within the ring circuit inline with the requirements of the Wiring Regulations.

Back over to you. 

It is better to apply a small twist to two or more C.P.C.s at a socket outlet and then put it into just one earth terminal. They then stay together. That is a much more reliable option in my opinion than just putting conductors singly. They never just fall out using this method. In your example the C.P.C.s fell out of the terminal due to a loose earth terminal, not due to the twisting together. But I would never twist 2.5mm2 solid conductors.

Z.

Sparkingchip: 
 

Since then most manufacturers have introduced double earthing connections on socket and other fittings as “Hi integrity earthing“ with the expectation that the CPCs will be connected separately to each of the two earth terminals to create Hi Integrity Earthing within the ring circuit inline with the requirements of the Wiring Regulations.

Back over to you. 

Did you notice, in the Draft for Public Comment of Amendment No. 2, Regulation 543.7.1.204 (independent termination where two protective conductors are used to provide reinforced earthing for high protective conductor currents) is proposed for deletion?

whjohnson: 
I'll bet these guys are registered contractors too, although I saw what looked like a military insignia on his shirt sleeve, a 12 week course finisher prior to leaving the armed forces?

EDIT: Check end of video - 24:48 in!

It's a hoofing great veteran's badge. Less than 12 weeks!

But it seems that they were having a giraffe. You have to watch the last bit to find out.

I am very surprised that they didn't divide the ring as far as they could reach under the floorboards, which would have avoided the JB.

I hope that they stuck a 2 colours warning sticker on the CU before they left.

Did you notice, in the Draft for Public Comment of Amendment No. 2, Regulation 543.7.1.204 (independent termination where two protective conductors are used to provide reinforced earthing for high protective conductor currents) is proposed for deletion?

I hadn't (probably not aided by the lack of change bars in the DPC (grumble grumble…) and possibly feeling I'd possibly said enough about section 54 on the subject of foundation electrodes!)

Given that the vast majority of c.p.c. failures I've seen have been at terminations (rather than along cable runs) - I can't help wondering what the underlying logic behind the change is (especially as the requirement for duplicate c.p.c.s. remains).

   - Andy.

Did you notice, in the Draft for Public Comment of Amendment No. 2, Regulation 543.7.1.204 (independent termination where two protective conductors are used to provide reinforced earthing for high protective conductor currents) is proposed for deletion?

In a word, no.

And there’s me having been putting ring circuit CPCs into adjoining earth bar terminals when there’s space with the conductors tied together with cable ties, as I do with line and neutral to make it clear which pairs go together.

All these little habits and rituals I have created for myself being an anorak are going to prove futile ?