Main eath bonding

twist · May 12, 2013

My water enters at the front of the house, from the crawl space then skims earth/whatever I keep there and enters the meter at the rear of the house, 15-20m away. If I collared the water pipe at the front for an earth bond it would hardly be accessible. Should I photograph it for the spark who fixes my CU or will he be able to determine suitability through impedance tests?

Octopus · May 12, 2013

twist said:
My water enters at the front of the house, from the crawl space then skims earth/whatever I keep there and enters the meter at the rear of the house, 15-20m away. If I collared the water pipe at the front for an earth bond it would hardly be accessible. Should I photograph it for the spark who fixes my CU or will he be able to determine suitability through impedance tests?

It needs to be accessible.

Redvanman · May 12, 2013

You want to connect the earth just after the main stop cock which would need to be accessible any way.
hope I've understood your question

Engineer54 · May 12, 2013

Eaisest way would be to cut a trap in the floorboard directly above the bonding position. It would then be classed as accessable!!

Stroppy · May 12, 2013

Perspex panel, so you don't have all the bother of finding the trap!

twist · May 12, 2013

Perspex panel? Under the front door mat? "Aw, Mr Bond, we've been expecting you!"

I think I'll dry line the earth floor and let the inspector/spark crawl along if he wants to see it. The Water Company's cock is at the front, mine is at the rear, after the inlet branches to the upstairs flat. The gas bonding will run a similair course and the gas entry point is similarly buried, although not quite under the floorboards. Just seeing the bonding is no guarantee of a good connection, I don't really understand the significance of it being accessible.

Geordie Spark · May 12, 2013

twist said:
Perspex panel? Under the front door mat? "Aw, Mr Bond, we've been expecting you!"

I think I'll dry line the earth floor and let the inspector/spark crawl along if he wants to see it. The Water Company's cock is at the front, mine is at the rear, after the inlet branches to the upstairs flat. The gas bonding will run a similair course and the gas entry point is similarly buried, although not quite under the floorboards. Just seeing the bonding is no guarantee of a good connection, I don't really understand the significance of it being accessible.

Champion!!

mg_smile::thinking::whatchutalkingabout:hanged:

happyhippy68 · May 13, 2013

twist said:
Perspex panel? Under the front door mat? "Aw, Mr Bond, we've been expecting you!"

I think I'll dry line the earth floor and let the inspector/spark crawl along if he wants to see it. The Water Company's cock is at the front, mine is at the rear, after the inlet branches to the upstairs flat. The gas bonding will run a similair course and the gas entry point is similarly buried, although not quite under the floorboards. Just seeing the bonding is no guarantee of a good connection, I don't really understand the significance of it being accessible.

The requirement for it to be accessible is to allow for future inspections and verification of continuity. I have seen many bonding clamps that have corroded through or rusted so badly that although it is connected there is no continuity. This would then give rise to the possibility of not completing the fault path during an earth line fault and therefore not operate the protective device for the faulty circuit within the required time. This could lead to a fire or a very dangerous shock for someone.

Deleted member 9648 · May 13, 2013

happyhippy68 said:
The requirement for it to be accessible is to allow for future inspections and verification of continuity. I have seen many bonding clamps that have corroded through or rusted so badly that although it is connected there is no continuity. This would then give rise to the possibility of not completing the fault path during an earth line fault and therefore not operate the protective device for the faulty circuit within the required time. This could lead to a fire or a very dangerous shock for someone.

You've lost me on this one....whats the bonding got to do with fault paths and operating protective devices? Are you suggesting we can rely on bonding to operate a protective device?

Octopus · May 13, 2013

twist said:
Perspex panel? Under the front door mat? "Aw, Mr Bond, we've been expecting you!"

I think I'll dry line the earth floor and let the inspector/spark crawl along if he wants to see it. The Water Company's cock is at the front, mine is at the rear, after the inlet branches to the upstairs flat. The gas bonding will run a similair course and the gas entry point is similarly buried, although not quite under the floorboards. Just seeing the bonding is no guarantee of a good connection, I don't really understand the significance of it being accessible.[/QUOTE]

To many DIYer's this isn't clear either but for those who know, understand and apply the regs its perfectly clear. Accessible means for visual and testing now and in the future.

happyhippy68 · May 13, 2013

wirepuller said:
You've lost me on this one....whats the bonding got to do with fault paths and operating protective devices? Are you suggesting we can rely on bonding to operate a protective device?

No I am suggesting that it is possible for a class 1 appliance to be live due to a fault but not operate the protective device until you come along and touch it and something that should be bonded such as a radiator thus giving a fault path to earth. If the fault path + R1 does not cause the protective device to operate within the required time then you have a potentially very bad day! That is the whole point of equipotential or supplemental bonding and testing it for continuity. It is also the reason we have to test it in special locations that are not RCD protected.

44ALLAN · May 13, 2013

I always thought earthing tripped the protective device....................oh well.

Deleted member 9648 · May 13, 2013

happyhippy68 said:
No I am suggesting that it is possible for a class 1 appliance to be live due to a fault but not operate the protective device until you come along and touch it and something that should be bonded such as a radiator thus giving a fault path to earth. If the fault path + R1 does not cause the protective device to operate within the required time then you have a potentially very bad day! That is the whole point of equipotential or supplemental bonding and testing it for continuity. It is also the reason we have to test it in special locations that are not RCD protected.

Your logic defeats me I'm afraid. Why should a radiator be bonded?

44ALLAN · May 13, 2013

"That is the whole point of equipotential or supplemental bonding and testing it for continuity".

No it isn't !!

Earthing and bonding are completely different beasts and should be treated as such.
If bonding produces parallell paths that a fault current 'might' take, then all well and good.

Earthing is there to clear the 'earth fault'...................not bonding.

Gawd..........................................

Brightspark2 · May 13, 2013

happyhippy68 said:
That is the whole point of equipotential or supplemental bonding and testing it for continuity. It is also the reason we have to test it in special locations that are not RCD protected.

What about so in the event of an earth fault all parts/metal work are brought up to the same potential and thus leaving no potential difference between simultaneous accessible parts...