Bonding Location

[Smugley]

Just wondering if there is a consensus on this or if it is another divided issue.

When selecting a location to main bond say the incoming water pipe, you need to be within 600mm of entry to the building, but the clamp must be accessible for inspection. Sometimes I choose one or the other requirements to take precedence. For example in Victorian terraces where typically the water supply enters under the front steps and runs at ground level and pops up in the rear kitchen. Do you bond within 600mm of the pipe's entrance into the building structure, under the front doormat, making the clamp difficult to get to, or bond when the pipe enters the living space? Couldn't guarantee this won't be after any t-joints which may be there now or be added in future.

 

[malcolmsanford]

Many thanks for that.

In the event, I fitted the bonding clamp to the pipe & ran the 10mm yellow/green cable from the MET to it but left it disconnected from the clamp on the pipe.

When the inspector arrived to complete the EIC, I explained to him that the copper pipe was connected to plastic at both ends & asked him if he wanted the bond connected or not. Without any testing as you describe, he said he did so I connected it.

That is interesting, Can I ask what inspector it was , was it NICEIC or NAPIT, becasue I know it's a guide only but the OSG on page 29 Section 4.4 is quite adamant about bonding plastic pipes. There is a great chance that as the incomer is plastic and then plastic to where joints are on the boiler that that small section of pipe would certianly not be an extraneous conductive part, and not need bonding, but just to say bond it without checking is a little suprising.

 

[Geordie Spark]

That is interesting, Can I ask what inspector it was , was it NICEIC or NAPIT, becasue I know it's a guide only but the OSG on page 29 Section 4.4 is quite adamant about bonding plastic pipes. There is a great chance that as the incomer is plastic and then plastic to where joints are on the boiler that that small section of pipe would certianly not be an extraneous conductive part, and not need bonding, but just to say bond it without checking is a little suprising.

I agree with you, but after the controversy I caused when I asked the question at college, I thought I'd cover myself by running the cable in & not connecting it until told to do so (or not) rather than not run it in only to be told when the job was finished that it was needed.

The inspector was arranged by the customer - a builder - who was building this 5 bed self-build for himself.

During the whole of my time on site, I only met this inspector twice and honestly don't know anything about him.

I was surprised that he completed the inspection & test in less than 2 hours though & charged £90, I was expecting him to be there for half a day.

 

[malcolmsanford]

Lol I think we maybe going down the road here of a sparks/inspector signing off someone elses work. ...................... whoever it was perhaps is not a good an inspector as the builder thought.

 

[Geordie Spark]

Lol I think we maybe going down the road here of a sparks/inspector signing off someone elses work. ...................... whoever it was perhaps is not a good an inspector as the builder thought.

Yes ... quite !!

 

[IQ Electrical]

Many thanks for that.

In the event, I fitted the bonding clamp to the pipe & ran the 10mm yellow/green cable from the MET to it but left it disconnected from the clamp on the pipe.

When the inspector arrived to complete the EIC, I explained to him that the copper pipe was connected to plastic at both ends & asked him if he wanted the bond connected or not. Without any testing as you describe, he said he did so I connected it.

Just about sums it up really, he had no idea what he was looking at....

This is from Paul Cook at the IET and shows that the pipe described can't be an extraneous-conductive part.

Everyone knows that water and electricity do not
mix, that the risk of electric shock is greater when
there is water around. They know that the risk and
severity of an electric shock is increased as a result
of the presence of water. This may be the reason
for the concern that water in plastic pipes may
conduct electricity and that bonding is required.
Because of this, the IEE commissioned the
Electrical Research Association to carry out
measurements of the electrical conductivity of
water in plastic pipes.
The ERA tests confirm that tap water in a plastic
pipe is a poor conductor of electricity. One metre
of 15 mm diameter plastic pipe filled with tap
water from Leatherhead where the ERA are based,​

has a resistance of 100,000 Ohms. This one metre of

pipe will restrict currents to less than fatal values
and of course in practice, there would be many
metres of pipe between metal items of plumbing
equipment and earth.​

​

​

 

[i=p/u]

ive heard if concerned you could do IR test on it. how would this gtest be carried out

 

[IQ Electrical]

ive heard if concerned you could do IR test on it. how would this gtest be carried out

If you look at post 13 but change the figure to 22 kOhms then you have it.

The test is conducted between the MET and the part in question, using an insulation resistance tester.

If the value is greater than 22 kOhms then the part is not considered to be an extraneous-conductive part.

 

[i=p/u]

nice, i do understand, could you not just test between the nearest earthing conductor and part in question...

 

[IQ Electrical]

nice, i do understand, could you not just test between the nearest earthing conductor and part in question...

No, it must be the MET, that is your earth reference for the installation.

 

[i=p/u]

kk good to know

 

[i=p/u]

one more , do you use a wonder lead .one clip on met and other on part in question??

 

[IQ Electrical]

one more , do you use a wonder lead .one clip on met and other on part in question??

Yes a wander/R2 lead whatever you want to call it.