Where to bond?

[RF Lighting]

I was working in a terrace house recently. The cold water supply comes from the street into my cellar, and runs the full length of the cellar before branching off into a supply for my house and a supply for next door.

There is a stop cock in the cellar as the pipe enters my house, which supplies both properties, and then after the branch there is another stop cock which supplies my house only.

Where should this be bonded? Should it be where the pipe enters the house, or where it brances and becomes just my supply? The pipe could introduce a potential from both the front of the property AND where it passes through the party wall. Does it need bonding in both places?

I did a drawing

(Its not actually my house)

 

[Steve]

Slip a bit of plastic pipe in.

But serously, I dont see the harm in bonding at all points of entry, as long as the neighbours have the same earth arrangements.

 

[JohnD]

Well, the point of Main Bonding is to bond metallic services that could introduce a potential from outside... so the safety aspect must mean that it should be done at the point of entry.

Safety aspect is unaffected by who owns what part of the house.

 

[RF Lighting]

But does it also need bonding near the party wall, as next doors MEB could be at a different potential to mine, or does the metallic (lead) pipe suffice?

 

[EdwardCurrent]

Hello RF,

No pic ???
'They' say
The MEBC has to be within 600mm of the meter, or where the pipework enters the building ()if the meter is external too,
'before any branches' in the pipework will come into play maybe, as may the term 'main' stop cock as opposed to your own.

I think we can entrust you to bond and test the installation to your usual high standards.

Solder on. ( soldier sorry ).

Ed.

 

[Cremeegg]

Surprised to see you asking - you usually provide such good answers!. I'd bond at entry to your cellar as that's where it enters your house and your neighbour should bond where it enters theirs.

My turn for the question - Are you really going to get that different a potential to require bonding at either end of your cellar ? - which is I guessing no more than 50 feet.

 

[EdwardCurrent]

Ed.

 

[Cremeegg]

If its in a cellar - surely access isn't usually a problem - I don't see many that are underdrawn.

 

[RF Lighting]

All the pipework is fixed to the wall in the cellar, so no problem with access.

It was one of those situation where I jut wasn't sure. I would personally bond both places just to be sure to be sure

Nice to get others opinions tho. I wonder if Softus might give me a pointer?

 

[EdwardCurrent]

Do you think that your neighbour's should be bonded in the same way ??

 

[Pensdown]

As John has said, the point of Main Bonding is to bond metallic services that could introduce a potential from outside. For example, if RF bonded at his stop cock the section of pipe between the point of entry and the stop cock could be at a different potential if there was a rusty joint between the two. So RF should bond at the point of entry.

As for the neighbour, RF's bond should make their bond superfluous, however, they don't know that and as they have no control over RF's bond they also need to bond where it enters their property for the same reason John has stated.

I do hope Softus agrees

 

[plugwash]

the neighbours property is outside your equipotential zone and thier pipiping can introduce a potential.

imo best to bond at both entry points but as long as that whole section of pipe is soldered together i don't think it matters much.

 

[Pensdown]

Thanks plug, I did miss that the neighbour could have a water feed (in copper pipe) underground between the house and a garden shed/pond which could introduce a potential between RF's bond at the point of entry and his stop cock if the pipe was in a poor state of repair.

I'm surprised Softus missed that..

 

[JohnD]

On second thoughts, I see Plugwash has got it... in another way, the pipe from the neighbour's cellar is entering your property too, so (even though it's "the same" pipe, it enters your property twice so needs bonding twice.

Neighbor might have a stupid fault in CU or cut out, you never know; or an electrical supply from a different cable round the corner, or an incorrectly installed stand-by generator.