Earth Fault

[woodchopper]

Came across a problem when I was installing a one of those USB sockets in a ring main yesterday. Was using a Martindale ring main tester to check which circuit to switch off -when it showed up an earth fault - not just in that ring main but the whole house.
The house supply comes up from the garage 100yds away though an underground cable. I found the garage( on a separate circuit but supplied form the hasn't got an earth either or his brothers house either as it is run off the same cable - I know this is a dodgy set up but the owner is a **** and prefers to do things himself rather than spend a penny. However, checked all the earth connections at the board and looked all right.
the only thing I could think of is that the cable to the earth rod has rotted - tried to find it but it is buried in swampy water sodden ground outside the shed somewhere. I've told him to put a new spike in - What size rod and Cable size are required ??
I would have thought the house would still be earthed albeit through the water pipes? Told to get a Sparky in but as I said, prefers to do things himself.
The shed is at least 40yrs old and was the only building in the area with a supply at the time it was built. But two houses are now run of the supply cable with two separate meters.
What size of supply cable should that be?
You are probably wondering how the electric company connected it but that was dodgy too.
Hvaen't checked nut I dare say his brothers house is earthed either.

[New Judge]

"I know this is a dodgy set up but the owner is a **** and prefers to do things himself rather than spend a penny."

Strikes me that you may be doing the same. I think an electrician may be your best bet.

[youngmafbog]

Amending the eartg falls under Part P.

Clearly you dont know what you are doing to ask such a basic question so pleas get a qualified and regjstered electrician in who has the correct test equipment. Before someone gets killed.

[woodchopper]

It's not me you have to convince to get a spark in- I dont cut corners. I was looking for information rather than a verbal tirade.
Have it installed two earth rods before up to spec - but as regulations change over time was merely asking the correct size rod/cable.

[The Builder]

Sounds like a horrendous installation, Woody. Obviously I can't comment on the state of the supply cable, but You can at least make it safer.

Make sure the whole house is protected by an RCD... then ...

Install an earth rod just outside the house, as close as possible to the position of the consumer unit. Connect with 16mm earth cable.

NEVER rely on water pipes. That went out years ago. But... any incoming METAL water pipe should be bonded to the house earth (10mm cable).

It's essential that the external impedance of the earth rod is then measured. It should be no more than 100 ohms.

[New Judge]

"I was looking for information rather than a verbal tirade."

If "I think an electrician may be your best bet." equates to a verbal tirade I think I'll steer clear of any questions you might post in the future :-)

[woodchopper]

Thanks builder just what I was looking for - what size of rod 3/8" or 5/8"?

[Ryzen]

Use a 5/8 extendable type..then you can check the readings and add another if required.

[woodchopper]

Thanks builder just what I was looking for - what size of rod 3/8" or 5/8"?
The wiring in the house is fine - built 12 years ago - just the wiring in that shed is lacking.

[woodchopper]

By the way Builder, those gu10 fly leads were great apart from the termination block - made from aluminium and stripped out every block - lucky had enough of my own to replace it with.

[The Builder]

Yes, I agree... use a 5/8" rod. Costs around a fiver and gives more surface area. Easier to bang in too.