Earthing questions

[Peter Woodford]

Guys,

need some questions answered

1. when doing a earth loop test on stay a lighting circuit if you did'nt have the main earth connected to the board what reading would you get.

2. if you could'nt find the earth rod on a tt system but had a good reading would you have to install a new rod or would you put on cert could not locate.

3. if the gas meter was on ground floor (outside) and the flat was on the first floor would you have to connect the earth on the outside or could you connect to the gas supply to the boiler

cheers

 

[MarcT]

Hi peter,

the reading you would get off the lighting circuit would depend on the parallel paths present.

You would need to locate the earth rod, otherwise you cannot verify there is an earth to the installation, unless as you say, you take the Ra reading and note it as unverified.

i would say that the point at which the gas service enters the installation is adequate for bonding purposes

hope this helps.

 

[Peter Woodford]

the gas pipe can only be accessed at the other end of the flat were the boiler is so would i have to bond outside

 

[Des 56]

I suppose the politically correct anwer to No 1 would be that you dont do an earth loop test on a circuit without that main earth,but I would say the same as Marc T you would be measuring parrallell paths,so unknown

You could take areading off what you believe may be the earth wire,but you are supposed to verify the continuity,so if its buried it should still be made available for inspection
and
No 3 as stated
If the first exposed part of the pipe is at the Boiler and the flat is your equipotential zone,then yes at that nearest exposed part,if the flat is sub mained, then main bond at intake to met and another gas bond at the flat to its DB