skts x 2 earth terminals

[driverman]

Been 2nd fixing today, which i've not done for many years. I've noticed that both Volex 13A twin & single sockets have 2 x earth terminals. Is that now standard? I thought that requirement was only applied to sockets that served a lot of IT equipment. Even years ago i would sleeve the earths separately, but then into one terminal. Is there any electrical reason for the change? Thanks

 

[driverman]

Awww now i'm thinking put both earths into one terminal! Which is what I have been doing for years!

 

[Doomed]

No matter what you do it will be wrong somehow.

Especially if your married.

 

[driverman]

No matter what you do it will be wrong somehow.

Especially if your married.

Baffled....although had a few drinks hic

 

[wildgoose]

Decent sockets with double pole switching, will have 2 earthing terminals. The cheaper single pole switched sockets - which I stay away from, normally have just the one earth terminal.

I personally will use both earth terminals on a newly wired sockets only because it looks better. On a refurb/replacement socket, I'll use whichever terminal is best for the existing cable length.

Earthing of the metal knockout boxes in domestic applications, is of course not required providing one of the mounting lugs is fixed.

 

[ayjay]

use tenby sockets
they have very fine terminal threads and don,t loosen

 

[Engineer54]

Well i would personally use one of the socket earth terminals for the rings circuit conductors, and the other for a flying lead to the back box. I don't really care what BS7671 has to say about relying on a face plate fixing screw, i was taught to use flying leads to the back box and see no reason not to continue to do so!!

 

[shanky887614]

Baffled....although had a few drinks hic

nothing rong with that, just got back fron pub myself.

not completely out of it yet, but i need to take extra care wiyh spelling

 

[wildgoose]

Nothing wrong with flying earth leads inside the boxes - I was taught that way back too. However, back in the old days of the 60's & 70's, you really did need flyleads. Limited use of rcd's and no knockout box grommets was common place - how many original socket boxes from this era do you find without any grommets?

 

[Simlec]

There does appear to be a misinterpretation of the requirements for 2 separate CPCs for such circuits.
One conductor run in a ring formation and terminated at separate terminals does not equate to two CPCs.
It needs two separate conductors, each connected to a separate terminal in order to comply.

Im not sure what your saying Spin?
Are you saying the image (for example) in Guidance note 8 page 132 is incorrect!
As it says on page 131 that if the ends of the protective conductor are separately terminated at DB & sockets then Reg 543.7 will be met as shown in image

 

[onions1066]

Hey guys. Haven't been on in a while but is this really what it's come to arguing over how many earth terminals to use in a domestic socket. Does it actually matter. ...........

Sent from my GT-I9505 using Tapatalk 4

 

[UNG]

ugh, twisted earths, the bane of fault finding / testing!

You forgot the twisted live and neutrals for extra grief just weakens the cable IMO

Exactly, never have liked twisting conductors together. As an apprentice years ago, it was the norm to twist (was imperial then) conductors together. When metric cables came out, many electricians still twisted conductors together. In my opinion very bad practice. I doubt if many twist conductors together nowdays! Or do they ?

There are people who still do it they should have their pliers confiscated

There are arguments for both.
Twisting together would allow for continuity of the conductors, if the terminal became loose.
Twisting together restricts the number of conductors that can be terminated.
Twisting together is a pain when it comes to testing.

I think people who do are just twisted

i can't see it making any difference what so ever. However, as not in the game as such I just wondered why the introduction. Surly must be more expensive to produce, therefore there must be a reason why. Could it be an EU instruction?

It probably won't make much difference to the Bob's in the factory whether it has one earth terminal or two

EU are not interested in UK sockets....the reason is manufacturers dont have to manufacture both types....cheaper to tool for one only,and the extra cost of the two terminals is sneaked onto us.

The mouldings on a lot of sockets these days universal so they can have one or two earth terminals, the extra cost of the second earth terminal is probably only a few pence

In fault-finding an RFC with a higher-than-expected value for r2, on at least a couple of occasions it has turned out to be due to relying on the socket internal metalwork.

One end of the RFC into one terminal, the other end of the RFC into the other terminal. Screws done up tight. But the sockets had riveted bits of metal work, not always making good contact. I've seen sockets with the best part of an Ohm measured between the two terminals.

Had this a few times I also find the switches can be a bit hit and miss when doing R1 - R2 tests

 

[Deleted member 9648]

You forgot the twisted live and neutrals for extra grief just weakens the cable IMO



There are people who still do it they should have their pliers confiscated



I think people who do are just twisted



It probably won't make much difference to the Bob's in the factory whether it has one earth terminal or two



The mouldings on a lot of sockets these days universal so they can have one or two earth terminals, the extra cost of the second earth terminal is probably only a few pence



Had this a few times I also find the switches can be a bit hit and miss when doing R1 - R2 tests

Those few pence per socket add up when you are mass producing.

 

[Tidy Max]

Im not sure what your saying Spin?
Are you saying the image (for example) in Guidance note 8 page 132 is incorrect!
As it says on page 131 that if the ends of the protective conductor are separately terminated at DB & sockets then Reg 543.7 will be met as shown in image

That is specifically for circuits that have high protective conductor currents. Which is what Spin is saying.

In the post that you quoted he is saying in a normal RING circuit there is only ONE cpc.

 

[Simlec]

That is specifically for circuits that have high protective conductor currents. Which is what Spin is saying.

In the post that you quoted he is saying in a normal RING circuit there is only ONE cpc.

​Are you sure?

 

[Tidy Max]

Yes i am sure! You may have two ends but its two ends of the same cpc! There aren't two seperate circuit protective conductors! Once again i will totally hold my hands up if i am getting the wrong end of the stick which is usually the case!