Find electrician to trace earth leakage

[naylorpd]

OK, so this is a follow-on to my thread about unsatisfactory EICR.

There is a big inconsistency in that the EICR reports all the L-E IR as >100 Megs, but the inspector also comments about earth leakage in two ring mans and one lighting circuit. This seems to be stopping me from replacing the CU and related C2 problems because RCDs will trip constantly (as I understand it).

The guy that did the EICR advised that the earth leakage was measured and the readings were off the scale, and he just didn't change the software defaults on IR (I interpret... he didn't check IR at all).

So my plan of action is to engage someone else to trace the faults, ideally on an hourly rate (probably plus call-out). I need to find that someone (in Reading/Tilehurst) - preferably experienced in fault-finding and not just installation.

What qualifications and experience do I need to look for and ask about? Which is likely to be more suitable, NAPIT or NICEIC?

What's involved in doing this kind of fault-finding? Is it likely to mean disconnecting all the sockets and light switches to test the bare cables?

Thanks

 

[PEG]

I do always wonder if there is a reason why the SMPS in these sockets isn't fed from the switch. It seems to be a simple solution to the problem and means you're not leaving the power supply permanently on.

Good point,but i have asked this question,and it's down to two reasons. One is,the switched outlet may be an appliance which zeros out,memory wise,when the power is cut,so inconvenient....

Two,is additional moving parts,and tooling requirements,for extra switch...therefore more cost= less profit.

....I wonder which one guided that production decision

 

[naylorpd]

Its not just USB sockets that can get fried.... Electronic dimmer switches, PIR sensors, LED lights... nothing with electronics like having the 500vDC pumped through it.

Just been to see my tenant, who reported that after the inspector left, they realised that their fridge-freezer wasn't working. The engineer came and reported that the circuit board was fried. So it seems that the IR tests were done without unplugging everything...

 

[Octopus]

Just been to see my tenant, who reported that after the inspector left, they realised that their fridge-freezer wasn't working. The engineer came and reported that the circuit board was fried. So it seems that the IR tests were done without unplugging everything...

I refer you back to post #2

 

[DPG]

You've been given very good advice several times now. Now is the time to act on it.

'off the scale' - I do love accurate information. Were all circuits the same 'off the scale' figure? Presumably they were each different.

 

[littlespark]

So there is nothing wrong with the installation, just the appliances?
The initial EICR was possibly spot on, and a recommendation of a CU change was just that... a recommendation.
The "off the scale" sparky should have checked for appliances, but as mentioned before, there are so many things that can affect the readings.

 

[SJD]

Just been to see my tenant, who reported that after the inspector left, they realised that their fridge-freezer wasn't working. The engineer came and reported that the circuit board was fried. So it seems that the IR tests were done without unplugging everything...

Perhaps as well as a refund for what appears an incompetent EICR, you ought to request the "inspector" pays for the fridge/freezer repairs that they damaged while testing.

 

[Risteard]

I'll ignore the C3 on cables not buried >50mm, it's nonsense.

It's not nonsense - it is required to code any lack of RCD protection where now required with a minimum C3 observation (which could be given a more serious observation depending on the details).

 

[Wilko]

Hi All - @naylorpd was mad kind enough to let me in for a look at the problem.
On arrival, clamping the tails did reveal a standing leakage of 70mA so there was likely to be a problem to solve. It turns out a fried USB outlet and a kitchen RFC fault were the major contributors. Fixing these two has reduced the installation leakage to 10mA with all appliances and boiler running etc.
The installation is 1980 (ish) TNCS PME , controlled by the original Wylex board with push button 5,15 and 30A mcb. There was a new kitchen fitted 10 years ago and one of the wall units has a mounting point in the middle of the cable safe zone. And sure enough probing the bracket through the back of the cupboard showed connection to the ring. Due to domestic practicalities we decided to deal with Kev's Revenge by disconnecting the damaged section for now. The RFC is now 2 radials with 15A OCPB, until a more convenient time to dismantle the kitchen, dig out the cable and repair it.

 

[naylorpd]

There was a new kitchen fitted 10 years ago

One year ago, not 10!
Main leakage was neutral to earth, not live to earth.
And lots of fun finding extension leads with surge protection stuffed behind beds.
Now all clear for new CU - thanks @Wilko

 

[Deleted account]

One year ago, not 10!
Main leakage was neutral to earth, not live to earth.
And lots of fun finding extension leads with surge protection stuffed behind beds.
Now all clear for new CU - thanks @Wilko

Neutral is a live conductor .

 

[Octopus]

One year ago, not 10!
Main leakage was neutral to earth, not live to earth.
And lots of fun finding extension leads with surge protection stuffed behind beds.
Now all clear for new CU - thanks @Wilko

Interesting update. When you say all clear what are your ir readings now?

Fyi surge protection devices, rcd's and appliances will all give low and false IR readings ...

 

[Wilko]

Interesting update. When you say all clear what are your ir readings now?
Fyi surge protection devices, rcd's and appliances will all give low and false IR readings ...

Yes indeed, it did take a few searches to find them all.
The kitchen ring L+N to E at 250V was initially too low to read on my meter, but not a dead short. Deleting the damaged cable brought the 2 radials to about 200M. By conclusion the global IR at 500V was 40M Ohms.

 

[Pete999]

In reality no, but members of the public are encouraged to use accredited tradesmen because it supposedly gives them more assurance about the quality of workmanship.
As a landlord I have to be able to show that I took reasonable care in having my home tested (and soon worked on) by someone competent to do the job.

And there lies the problem.

 

[Octopus]

Hi All - @naylorpd was mad kind enough to let me in for a look at the problem.
On arrival, clamping the tails did reveal a standing leakage of 70mA so there was likely to be a problem to solve. It turns out a fried USB outlet and a kitchen RFC fault were the major contributors. Fixing these two has reduced the installation leakage to 10mA with all appliances and boiler running etc.
The installation is 1980 (ish) TNCS PME , controlled by the original Wylex board with push button 5,15 and 30A mcb. There was a new kitchen fitted 10 years ago and one of the wall units has a mounting point in the middle of the cable safe zone. And sure enough probing the bracket through the back of the cupboard showed connection to the ring. Due to domestic practicalities we decided to deal with Kev's Revenge by disconnecting the damaged section for now. The RFC is now 2 radials with 15A OCPB, until a more convenient time to dismantle the kitchen, dig out the cable and repair it.

That's top feedback mate ............ Shame the chap who did the EICR wasn't as diligent.