TT to PME

[Raney]

Hi

We moved into our house about 6 months ago. Soon after we were told that we had a TT supply and what appeared to be no visible earth rod, the only earth bonding was to the Gas main.

This is how we found the meter, earth wires and incoming supply.

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• Raney
• 16 Sep 2008
• 1

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• Raney
• 16 Sep 2008
• 1

After many calls to the DNO we have finally PME installed.

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• Raney
• 16 Sep 2008
• 1

The guy that did the conversion said we need to get a spark to connect the earth wires to the metal block, is there any reason why I can not? Surely its just a simple 5 minute job.

Thanks

 

[JohnD]

You can. It is not notifiable work.

See our Wiki if you are not familiar with this job.

 

[davy_owen_88]

You really should have the circuits tested to ensure that there are no other problems but technically there is no reason why you can not attach the wires to the earth block yourself.

I'd recommend isolating the supply before you do so incase you have an uncleared fault due to no previous means of earthing.

How old is the wiring in your house? Do you have RCD protection?

 

[Raney]

Cheers. Will take a look.

The house has no RCD protection and still has old rewirable fuses. However from the loft and airing cupboard the wire does look fairly modern PVC.

We are thinking about having a new CU fitted and if required a some sort of rewire, its just trying to find the cash!

Thanks again.

 

[plugwash]

You can. It is not notifiable work.

Unfortunately I beleive you are wrong there. Afaict the part P law has an exception for installing or upgrading main and supplementry equipotential bonding but not for installing or upgrading the main earth.

 

[ban-all-sheds]

If they're long enough (and they look as though they are), cut the old twisted-together ends off and strip back just enough for the earth block, and have 1 cable per terminal.

 

[FingRinal]

You can. It is not notifiable work.

Unfortunately I beleive you are wrong there. Afaict the part P law has an exception for installing or upgrading main and supplementry equipotential bonding but not for installing or upgrading the main earth.

Well spotted Captain...

 

[333rocky333]

Do any of the three actually connect to the CU.

 

[Pensdown]

If they're long enough (and they look as though they are), cut the old twisted-together ends off and strip back just enough for the earth block, and have 1 cable per terminal.

Make sure the installation is turned off at the CU main switch and then follow the above instructions. As noted, also make sure one connects to the CU.

You should do this ASAP because there is a very good chance your installation is without an earth.

I'm a bit surprised the DNO made it live and then left it like that.

 

[JohnD]

You can. It is not notifiable work.

Unfortunately I beleive you are wrong there. Afaict the part P law has an exception for installing or upgrading main and supplementry equipotential bonding but not for installing or upgrading the main earth.

'hmmmmmm
Hadn't thought of that.

But I would find it very difficult to recommend to Raney that he leave the G&Ys unconnected for even a day.

 

[sm1thson]

Unfortunately I beleive you are wrong there. Afaict the part P law has an exception for installing or upgrading main and supplementry equipotential bonding but not for installing or upgrading the main earth.

so basically he is 'allowed' to attach two of the 3 of them (the third one been the most important one). and as per JD's post above it is very unsfe without it connected.

(and I will reiterate the above advice (just incase the op missed it) to turn off the power before touching / attaching the cables, and whilst i am at it, i will itterate the question, does one of the G&Y cables to be attached to the block go to the consumer unit/fuse box?)

 

[Raney]

The three cables go in to the botton of the CU. But as far as I can see only two come out of the top. (I don't want to get to close to the cables)

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• Raney
• 17 Sep 2008
• 1

Would it be better to get a spark in just to be on the safe side?

Reason I ask is we have some new class 1 light fittings (purchased before we moved into the house!) that we would like to be installed. The connection of earth wires, earth check and light fittings could be done at the same time. Any idea how long that may take someone, and estimated cost?

Thanks again.

 

[davy_owen_88]

Obviously without being able to see inside the CU to check the connection what I am about to say is based on assumptions.

It makes perfect sense the you have 2 cables going straight through the CU - they will be your main equipotential bonding conductors and the other ends should be connected to your water and gas supply pipes.

The cable that probably terminates in your CU is the main earthing conductor.

I would suggest that you do call an electrican if you intend on fitting metal face plates because if you went for so long without an effective earth it is likely that there are other problems, possibly no earth continuity between light fittings etc.

The time it would take would depend on whether the circuit test results are acceptable - as it is a new PME supply I'd hope that Ze was confirmed so earth continuinty between MET and fittings, insulation resistance and earth fault loop impedance need to be checked before you can safely change plastic fronts to metal. If you have problems such as a break in earth continuity then the solution could be simply tightening some terminals or it could mean you need some new wiring installed. The cost will depend on the time taken and many other factors such as your location, the hourly rate of the electrician you use etc etc etc.

Best advice I could give would be to get recommendations from your friends/family and make sure he is registered with a self-certification scheme.

 

[Taylortwocities]

Davy, the web site you quote only lists ECA members

This one www.competentperson.co.uk lists all registered members and has been developed by a collaboration of all of the approved scheme providers and local authorities to provide the consumer with the ability to search for a Competent Person registered with any of the schemes.

 

[davy_owen_88]

Apologies, I only did a google search and thought with a url like partp that it wouldn't be dedicated to only one certifcation body. Probably should have paid a bit more attention to the big BRE/ECA logo...