ELI Reading above 200

[Echo the husky]

I've seen meter fitters test polarity at sockets before and after replacing the meter, to ensure the wiring is the same after the meter is replaced. Any wrongly wired socket would then show up before hand. It's good they check, we did a site of houses about 9 years ago, at the start we would do a second fix, then dead tests, then connect the tails to the meter and complete the live tests. About half way through EDF made some changes to how things were going to work and that they wanted to connect the tails at the same time as the meter was fitted, after being given a copy of the results of the dead tests. Trouble was a total of 3 houses ended up being connected backwards by the meter fitters. We'd then have to call them back to correct it.

The appliance man was probably just trying to ensure safety. Without a good earth a fault on an appliance could become a hazard. Many white goods are also fitted with substantial mains filters, the earth leakage from these is enough to cause an uncomfortable shock from the metalwork if it is not connected to a properly earthed supply. If he was to carry out the repair, and then inform the client of the issue, the majority of people wouldn't care, after all, the appliance is working again. The fault then gets left to cause trouble in the future.

 

[Taylortwocities]

Testing of the impedence of the earth electrode, and consideration of the >200Ω figure is always done on the electrode in isolation.
When the tumble man came, he would have tested the installation with main bonding to other services (water, gas, etc) still in place.
I would therefore expect the earth impedence to be much less in that case.

As above, I do suggest that you get an electrician to look at this as well as testing the earth rod.

 

[JohnW2]

Testing of the impedence of the earth electrode, and consideration of the >200Ω figure is always done on the electrode in isolation. When the tumble man came, he would have tested the installation with main bonding to other services (water, gas, etc) still in place. I would therefore expect the earth impedence to be much less in that case.

Indeed, particularly with my much-mentioned TT installation in mind, that was one of the first things which occurred to me. However, on reflection I realised that a fair number of properties these days will not have any effectively-bonded extraneous-c-ps - either because all services come in plastic or because people have obeyed the idiotic regulation and bonded on the 'wrong side' of an insulating segment/meter! ... so that (together with an iffy earth rod) could possibly be the explanation in the OP's case.

As above, I do suggest that you get an electrician to look at this as well as testing the earth rod.

Yes, I'm sure we are agreed about that - which is why I didn't bother mentioning issues such as you have raised.

Kind Regards, John

 

[John D v2.0]

Yeah when we had the meter guy doing work he checked polarity before and after at a socket, however when the dno changed the cutout they also checked the earth loop impedence before and after. And even cat scanned the incoming cable under the drive

Mind you the guy checking it before hand struggled because he used a plug in tester and all our sockets were above 1 ohm back then, eventually he tried the cooker socket and it was fine. The guys doing the work checked it directly at the main earth terminal.

 

[JohnW2]

Mind you the guy checking it before hand struggled because he used a plug in tester and all our sockets were above 1 ohm back then ...

Nothing wrong with that (provided they were not a lot above 1Ω), assuming the circuit was protected by a B32.

I'm not sure that the DNO (or meter guys) should be interested/concerned about the Zs of final circuits in the installation - they really should be looking at the EFLI at the DB or origin of the installation, shouldn't they?

Kind Regards, John

 

[John D v2.0]

True and maybe that was his next option, but I doubt they want to start cutting the power for checks like that, or worse still, working live. Most socket circuits would be fine.
And there were no b32s in sight, it was probably bits of cpc from 2.5mm t&e. I should mention that was before I sorted everything out it wasn't in a good state

 

[JohnW2]

True and maybe that was his next option, but I doubt they want to start cutting the power for checks like that, or worse still, working live.

Measuring the loop impedance at the DB requires no more 'risky' an operation than does measuring a voltage anywhere in an installation with a suitable insulated test lead/probe.

Kind Regards, John

 

[Iggifer]

Measuring the loop impedance at the DB requires no more 'risky' an operation than does measuring a voltage anywhere in an installation with a suitable insulated test lead/probe

Nit picking, but it's highly unlikely the DNO would ever take an EFLI reading at the DB, they will (almost) always do it at the head. Which is somewhat more risky - they're well trained enough.

Having said that, I was on a job where they installed a Lucy MSDB, the guy tested the EFLI when he connected the service cable. We had to get a DNO guy back because they'd locked it with a substation lock. The guy who came back to unlock it and check it was ok to enter service couldn't get a reading. Assured him the previous guy had 100% got readings on all 3 phases as I watched him do it. Previous guy had forgotten to put the link in between E+N, was SNE in the street but should have been CNE at the cabinet.

 

[JohnW2]

Nit picking, but it's highly unlikely the DNO would ever take an EFLI reading at the DB, they will (almost) always do it at the head. Which is somewhat more risky - they're well trained enough.

Agreed. I was really thinking about people in general. As you imply, DNO folk would probably do it at the cutout, but they are used to doing, and trained to do, such things!

Kind Regards, John

 

[Iggifer]

Agreed. I was really thinking about people in general. As you imply, DNO folk would probably do it at the cutout, but they are used to doing, and trained to do, such things!

Kind Regards, John

And more than likely not allowed in your DB! The way the stupid world is these days

 

[JohnW2]

And more than likely not allowed in your DB! The way the stupid world is these days

Very true

Kind Regards, John

 

[John D v2.0]

Sorry wasn't clear there, the dno sent the first guy to do a survey, he just checked everything and the jointers came over the next week to do the actual work. Opening the cutout would have exposed live parts and I can't imagine they'd work live when 99% of the time they can get what they need from a normal socket! However for there jointers they had to work live so the risk assessment is already there.