No Earth Apparantly

[david_galashiels]

The G&Y coming out of the ground is approx 0.7mm thick - there is only a green wire (approx 0.5mm thick) coming from the fuse box up to a brass connector that you can see just to the left of the meter name. The incoming feed does appear to be some kind of cloth material yes.

The g&y comes up out of the floor so no way to tell where it comes from underneath that without lifting the floor boards.

 

[david_galashiels]

I can't see a PME label.

What is the PME label?

 

[JohnD]

It's what you haven't got one of

"Protective Multiple Earthing" is a very common way for the electricity supplier to provide you with an earth. It means the cable is earthed at lots of points (so even if one gets detached it is likely still to work).

An installation with PME has to have a label saying so.

If you write to your electricity supplier requesting an upgraded earth they will quite likely give you a PME, or they might sweat a terminal onto the cable sheath.

Try to get a look under the floor boards. That G&Y might go to an earth spike; it might go to the cable sheath, it might go to a gas pipe or a water pipe which has to be done, but must not be the source of your main earth.

A modern earth usually has to be 16mm2 cable which is about 9mm diameter, but you have a big 3-phase service head so it might be different for you (it can be calculated but not by me).


BTW you might like to get one of these Socket Testers (about £10). It is not sophisticated enough to warrant that your installation is safe, but it can detect some basic faults.

And if you have a number of earth wires to connect, it can be convenient to gather them all together in an earthing block like this as your consumer unit may not accomodate them all

 

[securespark]

Can you lift the boards?

 

[Adam_151]

modern earth usually has to be 16mm2 cable which is about 9mm diameter, but you have a big 3-phase service head so it might be different for you (it can be calculated but not by me).

3 phase doesn't change anything with regard to earth sizing, and I'd just look at table 54G and use a 16mm² main earth conductor in this case, Pointless calculating it when the length of cable and thus saving is going to be very small

 

[Adam_151]

Can you lift the boards?

Yeah, I can lift a wylex standard board with perfect ease... even the metal clad ones

 

[securespark]

[Chuckle! Chortle!]

 

[gittish_bass]

does'nt David just need to remove the tar tape on the incomer and add an earth bond and cable of the correct size (16mm)then run to the earth block?

 

[Steve]

does'nt David just need to remove the tar tape on the incomer and add an earth bond and cable of the correct size (16mm)then run to the earth block?

No, his DNO needs to do this though.

 

[gittish_bass]

[How can I get an earth connection into the house - there doesn't appear to be any earth cable at the fusebox at all.
quote]

so this is acceptable for David but he needs who?[/quote]

 

[RF Lighting]

does'nt David just need to remove the tar tape on the incomer and add an earth bond and cable of the correct size (16mm)then run to the earth block?

The sheath of the cable may not necessarily be suitable for supplying the main earth. The best course of action is to contact your DNO and see what sort of earth, if any is available, and get them to supply it.

[How can I get an earth connection into the house - there doesn't appear to be any earth cable at the fusebox at all.
quote]

so this is acceptable for David but he needs who?[/quote]

I don't understand what you are trying to say / ask

 

[gittish_bass]

The earth block is visible in the photo, with cable in and out, Lead encased supply cable is the most likely for dom/install giving tn-s earthing arrangement albeit under sized. so Davids question was ( although I can't do that quote thing yet) 'How can I get an earth connection into the house '

My question on Davids behalf was - Earth clamp and 16mm earth cable to terminal block seems easy cost option - what's the expert opinion?

 

[JohnD]

The earth block is visible in the photo...

I think you're right, I didn't notice that little terminal on the side of the neutral link on the service head. I wonder if it might be an old TNC-S? Or if that was just a convenient place to put the terminal?

Anyone recognise it?


BTW David is not obliged to contact his DNO, he only has to contact his PES, who is responsible for knowing who the DNO is. In my experience it is better done by letter to Perth than by phone call to Mumbai.

... 'How can I get an earth connection into the house '

My question on Davids behalf was - Earth clamp and 16mm earth cable to terminal block seems easy cost option - what's the expert opinion?

I'm no expert, I'm a complete numbskull but amateur pipe clamps on cable sheaths are frowned on, they can damage the cable and may not provide a satisfactory earth. Far better to ask the Electricity Supplier to arrange a modern MET (which they probably will at modest cost). For the moment 16mm G&Y on that terminal would be a quick and easy improvement but would benefit from testing to see what it does. The terminal looks very small so I would say 1 16mm in there, going to a nice roomy 8-way block, then 16mm to the 2 consumer units (unless they have little earth terminals that will only take 10mm and 10mm to the main water and gas or oil incoming services. When the new CU is fitted, 16mm to that straight from the service head should do the trick and be neater.

 

[david_galashiels]

Thanks for all the advice guys - much appreciated, but I am a bit bamboozled by all the abbreviations. TNC? DNO? PES? I would guess that a qualified electrician could do the entire job and would also check that the earth requirements are being met.

This is the terminal block and the offending loose earth wire from the fuse box.

 

[david_galashiels]

Can you lift the boards?

I would think it should be easy enough to lift the carpet and boards to see what's underneath, however the people who were in before have put hardboard sheets down to cover and make a flatter surface rather than have the old floorboards.