Ra Too Low!

[dave2]

Got a call over the weekend from customer who has had her meter changed by NP****.

Meter guy has condemned  the installation as dangerous.

1.Ra is too low

2.Meter tails too small (6mm T&E)

On inspection Ra is 0.71 and yes the meter tails are too small but what did he do to the new meter?

You guessed it. He put the 6mm back into the new meter and sealed it up.

 

[Andy™]

the lower the better... although at 0.71, id guess the rod has hit something, either the metallic sheath of the supply cable, or a gas/water pipe

 

[dave2]

The earth rod looks pretty new in its shiney black box with 10mm going back to the board.

The incoming water is from a lead pipe which has a 4mm g/y  attached. Not sure where it goes to but will replace when I do the board change.

 

[Andy™]

rod was tested disconnected from MET, wasnt it?

 

[Sidewinder]

I doubt the meter monkey would have done that!

However, if Dave2 has the same result then we can only assume that for once the meter monkey knew what they were looking at.

If Dave2 has not done a full Ze, then I suspect, metallic services bonded, and the same at nearby properties and at least one or more on a TN supply, and thus perhaps an inadvertent connection between properties on the same supply phase via the metallic services.

 

[dave2]

Tested at the board(met) with 10mm disconnected but as I said there is a green 4mm attached to water and I dont know as yet where the other end is presented.

The lady said the meter man put a little box into one of her sockets and said the reading is too low.

 

[Sidewinder]

OK, typical meter monkey!

So your Ze between the disconnected earthing conductor, disconnected from the MET & the incoming live was 0.71 Ohms?

 

[samson337]

Maybe the water bond was connected to the rod ?

 

[dave2]

Maybe the water bond was connected to the rod ?

Maybe as gas bond and main earth are routed in same conduit up the outside wall  and into the loft.

Incoming water is on the other side of the house

The board is located upstairs and the property is an old terrace .

 

[Chewbacca]

where's the nearest sub-station or overhead transformer in relation to the property?

 

[dave2]

Will be working on these premises next Monday--will let you know the outcome.

 

[Sidewinder]

Please do, we would all love to know what you find!