Light switch earthing

[a1679]

Hi, excuse my ignorance on the topic but am concerned having read up on earthing. I may have understood incorrectly. Some light switches have the earth cable in connector and sockets do not have it connected to the box. My understanding is the back box needed to be connected to the earth?

Some faceplates are metal, some are plastic.

Any advice much appreciated, thanks!

 

[Jackrae]

All back boxes and metal face-plates should be connected to the cpc but more importantly it appears that the 2-way Wago connectors each have three wires inserted. The wago connectors can only have 1 wire per point so you need to change the neutral wago to a 3-way version and the cpc one to a 4-way or 5-way version, the extra ways being to accommodate the back-box and face-pale tails. The fourth photo shows too much copper exposed on the live line

 

[a1679]

All back boxes and metal face-plates should be connected to the cpc but more importantly it appears that the 2-way Wago connectors each have three wires inserted. The wago connectors can only have 1 wire per point so you need to change the neutral wago to a 3-way version and the cpc one to a 4-way or 5-way version, the extra ways being to accommodate the back-box and face-pale tails. The fourth photo shows too much copper exposed on the live line

Thank you. The Wago is a brand new install by contractors so concerned it's not correct. Where would the tails run to and from?

 

[Jackrae]

From cpc wago (1) to back-box and from cpc wago (2) to face-plate. Other three cpc leads (3,4 and 5) into wago (ie 5 in total)
Other opinions will vary
Do not replace any of the wago units unless you've first isolated the power at the consumer unit

 

[a1679]

From cpc wago (1) to back-box and from cpc wago (2) to face-plate. Other three cpc leads (3,4 and 5) into wago (ie 5 in total)
Other opinions will vary
Do not disconnect the cpc leads unless you've isolated the power

Thanks. So the CPC does not need to go direct to the back box or faceplate, the Wago box carries the earth? Forgive my lack of terminology knowledge!

 

[Jackrae]

Correct.

 

[opps]

Are the people that you are employing electricians?

I am not an electrician but all metal face plates should/must be earthed. Additionally, I would earth any metal back boxes.

As mentioned by @Jackrae there should only be one wire running into each port on those Wagos.

 

[a1679]

Are the people that you are employing electricians?

I am not an electrician but all metal face plates should/must be earthed. Additionally, I would earth any metal back boxes.

As mentioned by @Jackrae there should only be one wire running into each port on those Wagos.

Thank you. The picture with the Wago is brand new install by legit electricians subcontracted by builder. The other photos are from a kitchen I inherited but think is from the last decade.

My query arises from replacing metal plates with plastic ones in existing locations and taking a photo of a brand new light switch install for reference, which would seem is also wrong.

How would I go about earthing the boxes? In the socket example, the two earth wires go to the two earth terminals on the faceplate.

 

[opps]

Thank you. The picture with the Wago is brand new install by legit electricians subcontracted by builder.

Ok, image number 2 has a plastic face plate. Do any of the CPCs run back to the fixing point on the metal back box? Without it, in the event that a live cable pops out, the fixing screws running from the faceplate to the back back could become live.

I find myself wanting to be generous to your electricians, cutting them some slack, but I cannot.

Feeding 4 cables in to a fitting designed for 2 is wrong on every level. I cannot see any justification for that.

 

[Murdochcat]

The earths at the light switch should connect using the back box connection. Where you have a metal switch an earth cable should run from the same point in the back box to the earth connection on the switch.

With sockets the earths should connect at the socket. It’s not essential to have an earth lead from the socket to the back box

 

[opps]

With sockets the earths should connect at the socket. It’s not essential to have an earth lead from the socket to the back box

Why not?

If an earth on a plastic face plate pops out and hits the metal back box, the fixing screws will become live. I do not understand why any electrician would not reduce the risk of that happening.

 

[Murdochcat]

Why not?

If an earth on a plastic face plate pops out and hits the metal back box, the fixing screws will become live. I do not understand why any electrician would not reduce the risk of that happening.

Errrrrr

If an earth on a plastic faceplate pops out and hits the metal back box the fixing screws will become live

Are you sure about this statement?

Your earth should never be live unless you have fault

 

[opps]

Errrrrr

If an earth on a plastic faceplate pops out and hits the metal back box the fixing screws will become live

Are you sure about this statement?

Your earth should never be live unless you have fault

Fair call, I meant to say that if the live pops out and hits the back box (rather than the the earth) , without an earth at the metal back box, the face plate fixing screws will become live.

With sockets the earths should connect at the socket. It’s not essential to have an earth lead from the socket to the back box

Again, I am not an electrician, but what protection exists if there is no earth to the metal back box in the event of a live cable touching the metal back box?

 

[RandomGrinch]

As you, I am not an electrician...

If an earth on a plastic face plate pops out and hits the metal back box, the fixing screws will become live. I do not understand why any electrician would not reduce the risk of that happening.

Metal back boxes usually have a fixed lug (as well as an adjustable one), in which to screw the accessory into.
This fixed lug (and the screw connecting it) is sufficient to earth the back box (if the faceplate is metal, or the accessory is a socket).
The back box isn't required to be earthed independently, but it is considered good practice to run a flying lead between the two.

If the faceplate is plastic, the earth wires should be connected into the terminal on the metal back box (many plastic boxes also have a suitable terminal).

As opposed to what has been said above - I would run the primary earth wire/s to the place with the greatest risk, i.e. with a metal switch plate, I would run the earth to the switch plate itself, rather than having a flylead to the plate, from the back box.

 

[a1679]

Ok, image number 2 has a plastic face plate. Do any of the CPCs run back to the fixing point on the metal back box? Without it, in the event that a live cable pops out, the fixing screws running from the faceplate to the back back could become live.

I find myself wanting to be generous to your electricians, cutting them some slack, but I cannot.

Feeding 4 cables in to a fitting designed for 2 is wrong on every level. I cannot see any justification for that.

All the cables are visible in the photo, to the best of my knowledge there is nothing attached to the back box.

Three light switches and nine sockets have been installed in that job, I am terrified what may be amiss.