UK Main Earth Cable Source

[littlespark]

Notwithstanding the fact the pipe is plastic....

new boards still come with a earth bar inside, labelled, and there’s usually a “B” for bonding next to the numbered terminals for circuits.

saying that, if there is an MET, main earth terminal, then I’d use it.
It’s easier to test from, and you can visually check it without cover off board.

 

[timhoward]

If I still had a metal gas pipe coming into my house and the dedicated 10 mm earth cable from the main earth terminal was needed near the meter what exactly would this earth cable be protecting me from ?

In simple terms....
Firstly it prevents the pipe inside your house becoming dangerous to touch due to it becoming live from a source outside your house. The current path will be via the low resistance bond making the pipe safe to touch.
Secondly if the pipe became live inside your house, it protects someone outside your house being able to receive a shock by touching the pipe while standing on real earth as the current path would again be through the low resistance bond.
(Touching an insulated but live pipe inside your house is not something I'd volunteer to do but with dry hands wearing shoes is certainly less dangerous)

 

[Pete999]

When earthing gas and water service pipes do the 10mm earthing cables HAVE to come from the main earthing terminal (first tee) or can they come from a consumer unit that is connected to the main earthing terminal by a 16mm earth cable ?

What specifiacally do the relevant regulations say about this (my house was built in 2012) ?

I ask because Cadent recently changed the gas pipes in my street to plastic and they moved my gas meter nearer the road because the gas pressure was too low with the new thin pipes.

However they refused to earth the new copper gas pipe they installed inside my garage that connects my boilers to the new meter position.

They said the earth cable for the old meter position comes from a consumer unit after the first tee which doesn't comply with regulations and so they wouldn't earth the new copper gas pipe they had just installed.

Note there are three consumer units in my house each of which is connected to the main earthing terminal by 16mm earth cables which is why I have a main earthing terminal even though it's not directly used to earth the gas and water pipes.

On a wider note do you think Cadent are being reasonable or unreasonable as regards refusing to earth the new gas copper pipe in my garage ?

You aren't earthing the pipework, you are bonding them to ensure the pipework is at the same potential as the main earth conductor to your property, pedantic it maybe, but that is why they are called main bonding conductors. from the CU EARTH BUSBAR IMO

 

[DPG]

You aren't earthing the pipework, you are bonding them to ensure the pipework is at the same potential as the main earth conductor to your property, pedantic it maybe, but that is why they are called main bonding conductors. from the CU EARTH BUSBAR IMO

Indeed.