Bonding sizes.

[jparker3007]

hi guys
doing some remedial work to give a satisfactory grading after a periodic on a large commercial building, one of the items is the sizing of the gas bond. its done in 6mm. my argument is that it was designed that way when it was installed (30 years ago easily) so y does it need to be upgraded to 10mm? the other is the location of the water bond, no body knows the location of the incoming water services (managers been there 20 years and never found it) how can i give it a satisfactory without finding it? anydoby handy with adiabatic? lol

thanks

 

[telectrix]

you use the adiabatic to determine the required size of the main earth cable. if this gives 12mm or less then the 6mm bonding is suffficient. ( 50% csa of main earth conductor ). you will however have to find where the water supply enters the building.

 

[Electricalserv]

If the system is TNS or TNC-S 6mm bonding is a code 4. You can't give water satisfactory, you need to locate it.

 

[jparker3007]

could it come under whats reasonably practicable? and bond the water at the first location i could?

 

[Electricalserv]

Mate I'd say they are both code 4's. Inaccessible access to water or gas bonding is exactly that code 4.

 

[jparker3007]

so in your opinion do the work and issue cert wth the code 4s on it

 

[Electricalserv]

so in your opinion do the work and issue cert wth the code 4s on it

As its not a defect you don't have to put it right. Complete the PIR with code 4 for both. Explain that it does not comply with the 17th Edition and you advise that both be made to comply.

 

[Apollo]

Surely a maintenance bod will know where the incomer for the water is at? Ask them where the meter is and then you can trace back from there.

 

[jparker3007]

no they dont because whoever plumbed it fit stop taps at every sink and toilet so no need for them to worry. the incoming head is on ground floor the gas is on the 3rd!! so the water must be down road in park lol