Help! Never seen this before!

[Steve93]

I am installing solar to a house and this is there main incoming. I can’t see an Earth anywhere but test ZS across L-N coming out at 0.20. Then with gas bond disconnected is 0.38! But we only have gas bonding. No other earth anywhere. Anyone had this?

 

[Nigel]

It’s a old detached house which is a fair few meters away from neighbour. I am stumped atm

So with the gas bond removed there is no other earths connected to the CU earth bar apart from the final circuit earths?

 

[Steve93]

Not that I can see no

 

[Nigel]

Not that I can see no

Surely you can see the whole of the earth bar? Is there another earth or not? Your answer seems unsure so just need to clarify.

 

[Steve93]

So with the gas bond removed there is no other earths connected to the CU earth bar apart from the final circuit earths?

Sorry that’s correct yes

 

[Steve93]

Surely you can see the whole of the earth bar? Is there another earth or not? Your answer seems unsure so just need to clarify.

There is no other earths

 

[Octopus]

Old properties often have earth's from random sockets to the incoming water ....

 

[Steve93]

Old properties often have earth's from random sockets to the incoming water ....

As I can’t find an Earth would you suggest earth rod? Although this zs at db reading is so low

 

[Nigel]

I think you need to disconnect earths one at a time and see how the Ze fluctuates and hopefully when you remove one the results will go up massively. This should then point you in the right direction to where the the earth is currently coming from.

I would not resort to an earth rod yet until you get to the bottom of the where the earth is coming from currently.

 

[davesparks]

That is a lead sheathed cable coming in which should be connected to the ISCO sealing chamber and other ISCO boxes.

Inspect and test the cover of the sealing chamber to see if it is connected to the lead sheath and then test it to see if it gives a good Ze.

 

[Steve93]

Just t

That is a lead sheathed cable coming in which should be connected to the ISCO sealing chamber and other ISCO boxes.

Inspect and test the cover of the sealing chamber to see if it is connected to the lead sheath and then test it to see if it gives a good Ze.

just tried that and it wouldn’t pick an Earth up from the casing

 

[davesparks]

Just t

just tried that and it wouldn’t pick an Earth up from the casing

That’s not good, I’d suggest speaking to the DNO, they like to replace cast iron cutouts

 

[davesparks]

This is a page from the 1940 WT Henley jointing manual showing how to install these cutouts. You can see the earthing wire which should connect to the screws on the top of the cutouts and front of the sealing chamber.

 

[Lucien Nunes]

Steve93, I agree with the others about checking the present earthing config although you might find it has been relying on the gas bond, and anything else providing a bit of continuity is purely by luck. The service cable almost certainly has a good earth on its sheath although it doesn't look like it was made off.

But what interests me is that ISCo service head. That was probably a 3-wire DC service originally, pos and neg lines with separate cutouts (in this case each with two fuses) and a neutral. These are very scarce now and if the DNO are called to replace it, I will happily send you some loot to give them a drink to leave it behind, and ship it to us for the museum. Please give me a shout if you go down that route!

 

[Steve93]

DNO don’t seem to care! They bassicly told me to put it on a TT system. They can send someone out to see if it can be changed to PME but that’s a 5 week waiting time.

 

[telectrix]

DNO don’t seem to care! They bassicly told me to put it on a TT system. They can send someone out to see if it can be changed to PME but that’s a 5 week waiting time.

DNO coming on a slow boat from China? that lead time is a disgrace.