Earth problems

[Rincewind25]

I need to check if I have an earth connection and wondered if it was possible to use a miltimeter?

Basic story is that I recently had my drive relaid and in the process, discovered a gas leak. This resulted in the removal of the existing pipework and installation of new plastic stuff. It didn't occur to me at the time that the old metal gas pipework must have been providing my earthing connection!

Totally unconnected, the washing machine then packed up and when the service engineer came, he tested the earth connection and couldn't find one! This is clearly an unsatisfactory state of affairs and I have now put an earth spike into the garden and run a cable back to the earth connections.

I have a multimeter available and wondered if it could be used simply to check if there is earth continuity. I accept the arguments I have seen that it won't provide an indication of the quality, but at the moment, I just want to confirm that it exists.

Any help/suggestions would be appreciated.

 

[Spark123]

In order to check an earth you need an "earth fault loop impedance" (EFLI) tester". What you have attempted to create is called a TT system which in itself isn't wrong however as this uses the general mass of earth to return the current to the DNO transformer in the event of a fault you will need RCD protection to all circuits. The EFLI including the electrode still needs to be checked with an EFLI tester to confirm it is within spec.
Safest option I'm afraid is to call out a sparks.

 

[ban-all-sheds]

It didn't occur to me at the time that the old metal gas pipework must have been providing my earthing connection!

If it really was then your entire installation must be either:

a) pretty old, and you'd be strongly advised to have it inspected - there could be all sorts of other things wrong with it.

or

b) done by someone incompetent, and you'd be strongly advised to have it inspected - there could be all sorts of other things wrong with it.

 

[Rincewind25]

No need to be afraid!

However, what is a TT system and is there an alternative? I really want to make, for obvious reasons, that the house has an adequate earth connection.

 

[Rincewind25]

Sorry, should have said 'make sure' there is an adequate earth.

House is about 35 years old, so not that old in the scheme of things. Water already enters in a plastic pipe, so although there is earth bonding to the copper on the house side, earthing there probably has no effect and having had a look, I cannot see any other sign of an earth connection

 

[rebuke]

A TT system means that you are getting your earth from an electrode as you've indicated. What I would do, is ring your electricity supplier and ask them to put you onto TN-C-S (often called PME), where the earth comes in with the supply - I believe they are required to do this for you assuming the network in the area supports it. If you're lucky, it won't even require a new cable to be put in.

For more info on the various earthing types, see the wiki here: http://www.diynot.com/wiki/electrics:earthing_supply_types_and_bonding:earthing_arrangements

 

[Rincewind25]

Thanks to you all for the prompt responses. It is obvious that I need to make further enquiries elsewhere to ensure the safety of the system.