High Earth Loop Impedance Reading

Sloaneranger37

Hi there

I recently arranged for British Gas to come and replace my old boiler. As part of the pre installation process they did some electrical testing and found I have a high earth loop impedance reading on my electrics (approx 11.5 - apparently it should be below 0.8 for a TN-S system which I understand I have). BG won't go ahead with the installation until this is resolved and advised me to contact UK Power Networks and get them to take a look.

UKPN came out today and did some tests. They confirmed the earth loop impedance reading as fluctuating between 6 and 11.5. The main earth in my house is clamped to an old pipe and the UKPN guy seemed to think that the pipe may have degraded causing the earth loop impedance to increase. His advice was that it isn't UKPN's problem and I needed to get an electrician out to either install an earth spike or to potentially have my system converted (from other stuff I've read online I am guessing this would be to PME but he didn't actually mention this).

Just wondered if anyone had been in the same situation and if anyone knew:

Is it right that this is my responsibility rather than UKPN's?

Are the two options he told me the best available? I'm in central London with not much outside space so I'm guessing mucking around with sticking an earth spike in the ground will be difficult.

Any cost issues with either of the options?

Thanks a lot in advance!

brightontraveller

Sloaneranger37 wrote: »

Hi there

I recently arranged for British Gas to come and replace my old boiler. As part of the pre installation process they did some electrical testing and found I have a high earth loop impedance reading on my electrics (approx 11.5 - apparently it should be below 0.8 for a TN-S system which I understand I have). BG won't go ahead with the installation until this is resolved and advised me to contact UK Power Networks and get them to take a look.

UKPN came out today and did some tests. They confirmed the earth loop impedance reading as fluctuating between 6 and 11.5. The main earth in my house is clamped to an old pipe and the UKPN guy seemed to think that the pipe may have degraded causing the earth loop impedance to increase. His advice was that it isn't UKPN's problem and I needed to get an electrician out to either install an earth spike or to potentially have my system converted (from other stuff I've read online I am guessing this would be to PME but he didn't actually mention this).

Just wondered if anyone had been in the same situation and if anyone knew:

Is it right that this is my responsibility rather than UKPN's?

Are the two options he told me the best available? I'm in central London with not much outside space so I'm guessing mucking around with sticking an earth spike in the ground will be difficult.

Any cost issues with either of the options?

Thanks a lot in advance!

Something sounds bull not sure if it’s the bit about BG doing test:rotfl: , type of existing earthing, UKPN response? Whatever electrical system (earthing) you are supplied is suppliers duty too maintain it at no cost to you.?

tacpot12

The conversion will to PME. The DNO don't have to prove you with an earth unless they want to and these days that will mean paying. A local electrician should be able to give advice whether ground conditions in your area make PME or providing a local earth (via an earth stake) a better option. Both are safe if done correctly.

Sloaneranger37

Thanks both - I have a TN-S earthing system, main earth is clamped to the outside of the incoming supply. UKPN did some tests, cleaned and refitted the earth clamp, did some more tests (same result of 6-11.5 ohms) and then just told me it was an "inadequate earth" which I would need to get my own electrician to sort out.

Sounds like as it's the DNO's (UKPN) earth, they have to maintain it and the guy who came out yesterday just tried to feed me some BS about it not being their responsibility?

I have a local electrician coming out this week anyway so will report back on his advice too.