Concerned customer having cheap bill!

[Deleted member 54734]

Not sure if these pics are breaking the rules so I apologize if they are mr mod!

I've been having a few jobs lately where I wished I'd had my camera and today I did.
This may not be as good as one I had last week where the builders moved the cutout as it was in the way but because the incomer wouldn't reach they used a choc block, this was outside and of course the customer hadn't had any problems in the last 2 years

But anyway I had a job today, the note on the job read something similar too "CUSTOMER CONCERNED OVER LACK OF USAGE (it does happen tho you wouldn't get me phoning up to tell them), PLEASE CHANGE METER AS IT MUST BE FAULTY!"

Elderly gent shouted me to come in (as he couldn't walk very well),
It's in the back he said, I had a electrician in a month or 2 ago to put me a new CU in and the last electricity bill I got was only £14 for the quarter.

Can anybody spot the deliberate mistake?

View media item 4423

 

[Chri5]

The electrician must have been named 'Robin Hood'.

He took pitty on the old boy and decided free electricity was the way forward.

 

[Lectrician]

Difficult to see where the tails where originally on the old board.

Sometimes the obvious is blinding!

 

[Spark123]

I'm finding it confusting as to why the meter tails have white paint on them, infront of the cutout?? Almost as if they have all been out and someone has put them all back wrong

 

[Deleted member 54734]

Is it common to have 2 RCD's on the one board BTW?

Surely one would protect the lot?

 

[oldman2]

New CU has been put in the place on the wall where the store heater rcd was originally, I think thats why the tails are painted.

Now had he kept quiet and used the night stores to excess I wonder if anyone would have noticed the billing differences?

 

[Spark123]

The external RCD is just for the storage heater CU at the bottom RHS, I can't quite make out what there is in the LHS CU, if there are two RCDs in the then you'll probably find one is 100mA (maybe also time delay type S) and the other 30mA.

 

[Deleted member 54734]

Hows this

View media item 4425
It needs 2 then?

Just curious.

 

[RF Lighting]

It's possibly an ex TT system which appears to have been updated to PME, and for some reason the electrician has treated this still as a TT supply.

Either that or he misguidedly thinks this covers the additional RCD requirements of the 17th edition.

 

[Spark123]

The one on the right is a Type S 100mA so the 30mA device it is feeding will discriminate against it, setup often employed in TT systems.

As this system is a TN then the 100mA isn't really required, under the 17th if there are any cables concealled in a wall or partition less than 50mm deep then they will need to be protected by a 30mA device, hence the new dual 30mA boards with a main switch. Some also have a couple of non RCD ways for RCBOs.

 

[plugwash]

So what did you do? quietly fix it? fix it and report it to your boss? call out some other department to fix it?

 

[Deleted member 54734]

It's possibly an ex TT system which appears to have been updated to PME

As this system is a TN

View media item 4424
Don't know if you can see in the picture but there is a sticker saying there is no earth connected.

This wasn't PME in the cutout as the link wasn't across.
The block did however help to light up my trusty test lamp with the other end on phase so I treated it as SNE as there are 3 earths in the block (one being painted white and disappearing through the hole on the right just below the board).
This explains the 2 RCD's then?

So what did you do? quietly fix it? fix it and report it to your boss? call out some other department to fix it?

The old guy obviously didn't do it himself as he could hardly walk never mind fiddle(either that or he's a damn good actor).

So I called one of my boss's who's quite clever, explained what had happened and got the ok off him to put it straight and not get the heavies in.
View media item 4433Must admit it was a bit rushed as It was 1 o'clock when I found it and I had 6 jobs left.

 

[RF Lighting]

Oh, that explains it.

It is common to use multiple RCDs in a TT system, as the EFLI is too high to automatically disconnect a fuse / MCB in the event of an earth fault as not enough current will flow to earth.

An RCD is therefore employed to disconnect earth faults, as it will operate with an external loop of upto 1666 ohms, which far exceeds the 100 ohms permitted by BS7671.

I just saw the earth block on the side of the cutout, and ASS-U-MEd an TN supply

 

[Spark123]

Yep, so it may very well be a TT system (earth electrode) as opposed to having the earth supplied by the cutout.
Do you carry an efli tester in your kit?
Seems odd to even touch the cutout earth terminal if it isn't connected - would be better if it was just from a separate MET.

 

[Spark123]

I just saw the earth block on the side of the cutout, and ASS-U-MEd an TN supply

You're not the only one there Rob, but we both would have picked it up with our efli testers