Changing Sockets?

[Kieran94]

Hi all ,

Well most of you experienced sparks will probably think this is a stupid question, however i have got a feeling something will go wrong.

My dad is changing the sockets/light switches from plastic to metal - which isnt the bit im worried about. The switches are wired in T&E and the cpc is running to the back box(metal). He was planning to take the cpc out of the back box & put it in the earth terminal of the switch. Can that be done?

Also with the plug sockets, they are double sockets and on the plastic have have 3 live, neutral and earth wires going to each terminal in the socket(again im not bothered about this) but then when we look at the metal socket there are 2 earth terminals for the top pin of the plug on each socket, how will he supply both the earth termials? do they both need to be supplied?(i think they do in my opinion).

Thanks for reading & i hope you can understand this

Kieran

 

[Dunc]

CPCs (earths) are always connected to the front plate with metal accessories so your Dad is correct on that one, the back box will gain its earth via the socket screws when the switch/socket is screwed back on to the back box. The second earth terminal on the socket is for instances where the socket will be specifically used to supply IT equipment, in this case you would therefore only need to connect all CPCs to one earth terminal (if they all fit that is).

as an after thought does your Dad own an earth loop tester? Always a good idea to at least conduct a quick loop test before fitting metal accessories in my opinion.

 

[malcolmsanford]

Providing that at least one of those lugs are fixed ..................it as always been regarded as good practice to have a fly earth to the back box but as Dunc as said it is not compulsory to do so, providing that one of the lugs on the box is fixed.

 

[Kieran94]

CPCs (earths) are always connected to the front plate with metal accessories so your Dad is correct on that one, the back box will gain its earth via the socket screws when the switch/socket is screwed back on to the back box. The second earth terminal on the socket is for instances where the socket will be specifically used to supply IT equipment, in this case you would therefore only need to connect all CPCs to one earth terminal (if they all fit that is).

as an after thought does your Dad own an earth loop tester? Always a good idea to at least conduct a quick loop test before fitting metal accessories in my opinion.

Thanks for your reply, so basically just swap wire to wire in the correct terminals & make sure the cpc is connected to the front plate & unfortunately he doesnt at the minute... but soon hopefully i might...

Thanks again

Providing that at least one of those lugs are fixed ..................it as always been regarded as good practice to have a fly earth to the back box but as Dunc as said it is now compulsory to do so, providing that one of the lugs on the box is fixed.

Thanks for your reply

 

[Des 56]

In the event of live working(testing) on the open switch plate that relies on a fixed lug to earth earth the back box, its surly good practice to have an addtional independent fly lead to the back box, especially if there is no rubber grommet where the cable enters the metal box.
If the cable shaffs against the sharp metal edge,whilst the front plate is unscrewed ,the metal box could become live, with plate movement, especially if the outer double insulation TE has been stripped above the metal box entry point and thus vulnarable single insulation entry.

Whether you take the cpc to the plate then to the box or visa versa is often another debate.

Personally, cpc to plate first, then fly lead top metal box.

What
Words like "live testing of unscrewed sockets" will have the NIcey secret police raiding your buisness

Comments like that are not to be made in earshot of the H+S brigade
Thats why I limit my live testing nowadays to the minimum possible

urrrm ( clears throat after telling porkies)

 

[telectrix]

how????

 

[malcolmsanford]

how????

I think we are still going down the road of if the cable sheath damaged scenario.

 

[telectrix]

i meant how do you take a ZS reading at a switch without removing/undoing the front plate.

 

[malcolmsanford]

You got it.

Ive seen the double insulation stripped above the point of entry into a metal back box with no grommet and 'nicks' to the single insulation caused by the sharp 20mm entry hole.

As I said, the fix lug wont protect the tester doing a 'zs' at the switch but a fly lead would, should movement of the dangling switch plate cause the single insulated cables to rub further on the sharp metal entry hole edge, if that is he were to touch the back box.

I do commend your reasoning behind this, and being of the "old school" that still do fit a fly earth to my back boxes, more in honesty out of habit, than the thought I may be that unlucky to get a belt of a back box, there is nothing in the Regs that makes you need to fit a fly lead to that back box unless it comes under reg 543.2.7.

So though like you IMO it is "good practice", it is not compulsory under the regulations.

 

[telectrix]

You can't. I thought I was clear in explaining that.

The flylead protects the tester whilst the plate is off.

was a bit unclear . i read it as " not unreasonable to take a Zs reading without removing front plate ".
whereas i would have said " its not possible to......... "

 

[telectrix]

asocket , i agree with you for the sake of less than 1 minute , a bit of sleeving , best practice.

 

[SirKit Breaker]

Its always good practice to bond the box to the accessory. Just in case the accessory is removed but not disconnected or isolated, like when decorating etc.

Cheers.............Howard

 

[telectrix]

decorator slops paste in switch box. RCD trips. SAFE! but as it's now pitch dark wallpaper goes on sideways. can't win 'em all.