Bonding argument

[ezzzekiel]

metal stop tap then some plastic pipes which then return to copper, site manager insisted that no main bonding is required, i argue that a bond should still be in place however im now starting to doubt myself and cant find anything to back up my theory - whats your views.

copper stop tap....plastic pipework.......returns to copper pipework, plastic are a few feet in length?

 

[shaun123]

don't forget the bonding is there to equal out the voltage in the event of a fault therefore if there is still a possibillity of electric shock from an earth fault then bonding should be fitted.

 

[ezzzekiel]

thats my view, but as the feeds from stop tap are plastic then earth potential cant be introduced is his argument

 

[IQ Electrical]

I know I keep posting this and I know it's got 16th Edition references but the principles remain the same:

 

[Des 56]

If you have a read of this piece of advise off Paul Cook of the IET it seems to suggest that yes you do have to have main bonding

If the incoming pipes are made of plastic, but the

pipes within the electrical installation are made of
metal, the main bonding must be carried out. The
bonding being applied on the customer side of any
meter, main stopcock or insulating insert and of
course to the metal pipes of the installation.
The connections of the bonding wired to the pipes
has to be made with a proper clamp to BS 951
complete with the label “SAFETY ELECTRICAL
CONNECTION - DO NOT REMOVE.”
If the incoming services are made of plastic and
the pipework within the building is of plastic then
no main bonding is required. If some of the
services are of metal and some are of plastic, then​

those that are of metal must be main bonded.

My own take on this is, if the copper of the stop tap main bonded pipe is simultaeously acessable with the other copper pipes, they should be supplementary bonded to the main bond

 

[IQ Electrical]

Yes, that's it, taken from page 2 of the IET Earthing Plastic Pipes Guidance.

 

[NMc]

Des 56 is correct if you have non plastic water pipes you need to earth them using the main protective bonding conductor.

 

[ezzzekiel]

only reference i found is in scadden book,
q. what do i do when pipework is mixture of metal and plastic?
a. no bonding required.

 

[IQ Electrical]

That's also covered in the guide that I attached.

 

[ezzzekiel]

my answer was i would normally clamp the stop tap and loop the earth round and clamp to the nearest part where it returns to copper and ive never given it much more thought.

reading your guide it states "If some of the services are of metal and some are of plastic, then those that are of metal must be main bonded."

Which is pretty much as i have said. Been looking it up and getting a lot of conflicting answers. Although i do understand his argument i thought there would be a regulation to back it up, gonna print the guide you attached and use as my argument.

 

[kmcgold]

see page 29 onsite guide 4.4

i would get the site manager to confirm in writing that any metal pipe work within the building
is not introducing earth potential no bond required.
but if i was not sure i would bond it.

 

[SimpleSimon]

If the stop tap and copper piping are simutaneously accessible than I would supplementary bond between these two to bring them to the same potential and main bond the cock stop. A potential could still be introduced if a fault was to appear whilist someone was touching both parts.
PS. Did you say it was plastic before the cock stop?

 

[gamblor6]

thanks for that pdf iq. i never knew bonding only applied if the fitting was in the zones

 

[Des 56]

PS. Did you say it was plastic before the cock stop?

Is a cock stop a woman with her legs closed

 

[ezzzekiel]

Did you say it was plastic before the cock stop?

not sure on that, stop comes straight from ground so couldnt tell. going to speak to qs tommorow for his view before putting it to site manager as his sig will go onto cert also.
Site manager is a heating engineer who also insists on cross bonding at boiler .....sigh