Bonding to main gas and water

[aaelectric]

Went to look at a cu change first inspected the gas and water bonding,
lathe meter for gas is 2 floors down and no access the pipe that comes into the house goes under the floor to the boiler. There is no access to fuse board I could not find main water looked under sink and all is boxed in. War would you do. Of the continuity test was under the 0.05 would you say it's ok

 

[malcolmsanford]

First off ascertain that the gas pipe is in fact an extraneous conductive part, chances are it is but you need to make sure it is.

Then confirm that the water pipe that is boxed in is bonded back to the MET, and agian if it is not then make sure it is also an extraneous conductive part.

If they both are then they need bonding as per regulation 411.3.1.2 and that is a fact. There are of course ways you can bond the pipe, as reg 544.1.2 tell us it must be as near as practicable to the point of entry, which is not always the case. So if you bonded where it is practicable and made sure that all the pipework that was extraneous was had the continuity of that bond then I would just make a note on your EIC of what you done

 

[telectrix]

what do you mean by no access to fuse board. ???

 

[i=p/u]

couldnt you just test between Met and taps with continuity tester or insulation resistance between MET and point in question

 

[Deleted member 9648]

You cant really go by continuity tests.....almost inevitably parallel paths will give a false impression. I'll wager on many installs you would get pretty near identical readings whether bonding is present or not.
If the system is TNCS IMO you will have to confirm main bonding to extraneous services...TNS or TT may be a little more flexible,your call,your name on the cert. Have you looked in the CU??.....a couple of 10.0mm's going out will at least give an indication.

 

[i=p/u]

so the test of 0.05 is pointless in your eyes, you would rather see it, and if a plumber sticks in plastic fittings does it still need to be bonded

 

[Deleted member 9648]

so the test of 0.05 is pointless in your eyes, you would rather see it, and if a plumber sticks in plastic fittings does it still need to be bonded

IMO it is rather pointless...it does not prove the presence of main bonding where it is required but is not visible. Whats plastic fittings got to do with main bonding an extraneous conductive part entering a building?

 

[i=p/u]

ok forget the plastic fittings... on sinks etc... so what test do you do if you cqnt see the bonding but your getting 0.04 ohms when you continuity test

 

[Richard Burns]

The 0.05 ohms continuity test is used for checking if there is supplementary bonding in place, where it is required but cannot be seen if it is boxed in. If the continuity between cpc and exposed / extraneous conductive parts in the area is <0.05 ohm then the supplementary bonding can be considered in place.

For main bonding you should be able to see and access the connections (often not the case), the connections must be to BS951 and you must prove continuity from the incoming service to the bonding conductor connection at the MET. Then you get into the csa requirements.

 

[telectrix]

and if you ain't got a BS951, drill the pipes and fit with a self-tapping screw. use a bit of PTFE tape to stop the gas and water leaking out. OH, Sorry, thought i was on the plumbers forum.

 

[mcauto]

so the test of 0.05 is pointless in your eyes, you would rather see it, and if a plumber sticks in plastic fittings does it still need to be bonded

afaik, no as u would be introducing a fault path

 

[aaelectric]

what do you mean by no access to fuse board. ???

Where the gas pipe is there is no way of pulling a cable threw without major damage

 

[telectrix]

then you have to fix wherever you can as near to the point of entry as possible. then explain on your cert. why.