No earth in garage - should I be worried?

Joe Smith · Dec 21, 2018

Hi,

We recently moved into a new house about 6 months ago and all of the plug socket wiring seems to have the standard, live, neutral and earth wiring as one would expect. However, go out into the garage (separated from the house) and it appears to only have Live and Neutral wiring (old style red and black respectively).

I only found this out recently after changing the facia and backbox to a plastic one as the old one was metal and rusted only to find 2 wires.

My question is, should I be worried and should I get an electrician to come out and quote to rewrite the garage? It seems like a big job as it looks like the wiring goes under ground potentially and is concreted in.

Thanks for any advice.

westward10 · Dec 21, 2018

Can you show any pics of the wiring Chris.

Joe Smith · Dec 21, 2018

Here are some photos of the wiring and the socket/light switch. I have disconnected them as I didn't think they were safe, but this is essentially the wiring inside and it doesn't have an earth.

[ElectriciansForums.net] No earth in garage - should I be worried?

Zdb · Dec 21, 2018

You need to get an electrician to perform a loop test and confirm the Zs on each outlet

westward10 · Dec 21, 2018

Those cables are MICC (mineral insulated copper conductors) and the copper sheath is the earth provided it is correctly connected at all points of termination. You are correct the existing accessories are corroded which is likely to affect earth continuity of the cables. As it stands you need to replace them with metal accessories to maintain the earth, with separate earth protective conductors from front plates to back boxes of the accessories. I would recommend getting an experienced electrician in as those cable glands require correct connection and retesting.

Squid · Dec 21, 2018

So, old house but new to you. That nipple switch must be a good few years old (the analysts will call it a toggle switch)

Squid · Dec 21, 2018

westward10 said:
Those cables are MICC (mineral insulated copper conductors) and the copper sheath is the earth provided it is correctly connected at all points of termination. You are correct the existing accessories are corroded which is likely to affect earth continuity of the cables. As it stands you need to replace them with metal accessories to maintain the earth, with separate earth protective conductors from front plates to back boxes of the accessories. I would recommend getting an experienced electrician in as those cable glands require correct connection and retesting.

Nice one, as they where so blackened I didn't notice, must be a lot of damp in the place.

Pete999 · Dec 21, 2018

It looks like the sockets are installed using MICC or Mineral Insulated Copper Sheathed cable, whereby the Copper sheath was is acting as the cpc (Earthwire)

However if you say you took the socket away from the box and there was no earthwire, the socket would have been earthed, but as soon as you removed it from the back box there would be no earth on the faceplate, the Electrician should have provided a fly lead from the back box to the socket.
You will be hard pressed to swap the back box with this type of installation, as disturbing any MICC cables is fraught with dangers unless you have experience of this type of cable.
If you are still intent on swapping the sockets and back box, then consult an Electrician to do the work for you, he can swap both the back box and socket with a nice new shiny one, shouldn't be that expensive, of course that depends on how many you want changing, sorry for the long post. Good luck, post your postal area and a member may live close to you and may offer to do the work, for a price of course.

Squid · Dec 21, 2018

Piranha nut springs to mind.

Squid · Dec 21, 2018

Or replace with a Crabtree metal box or terminate the MICC to a metal box that then feeds a socket, either way best to get an electrician in.

westward10 · Dec 21, 2018

Biggest problem is imperial size glands which are too small for 20mm knockouts and no good for Piranha nuts.

Pete999 · Dec 21, 2018

SWD said:
Piranha nut springs to mind.

Don't suppose they had heard of those things back when that install was done, earthing was provided by proper installation methods and good workmanship, there ought to have been a lead from the backbox to the Earth Terminal on the socket faceplate, but should the OP decide to employ an Electrician to swap the sockets and backbox the a Piranha washer would be a good addition, along with a fly lead from Box to socket.

Joe Smith · Dec 21, 2018

Ok thanks for the advice. Imagine they are going to laugh at me for replacing another socket in there with a plastic one then...my postcode is ****** if anyone is available to come and quote. Thanks.

westward10 · Dec 21, 2018

Pete999 said:
Don't suppose they had heard of those things back when that install was done, earthing was provided by proper installation methods and good workmanship, there ought to have been a lead from the backbox to the Earth Terminal on the socket faceplate, but should the OP decide to employ an Electrician to swap the sockets and backbox the a Piranha washer would be a good addition, along with a fly lead from Box to socket.

3/4 Piranha nut, good luck with that