Plastic water pipe

[Elmer BeFuddled]

No s**t Sherlock!! Obviously it's an insulator!! So as I said it would be completely pointless bonding it!! But seen as how stupid the regs have gotten lately I thought I would ask advice of other qualified electricians. But then you always seem too get an keyboard warrior like yourself who feels the need to reply with an absolutely pointless reply!! If you don't have a positive answer too my question don't reply at all!! You absolutely utter moron!!

I quite agree. What's the point of having a Q&A forum if anybody asks a question they get shot down for being a Electrical Trainee?

I'm a 9MW, but have the latest regs quals.

Personally I always get confused over re-wiring sealed plug tops, but wouldn't dare ask for help here as I fear the ridicule that would fall upon my very tender (and sensitive) bonce would push me into a relapse.

With that, I'm off t'pub to watch the local derby.

 

[DNS1]

Plastic incoming pipe, no possibility of introducing a potential, so no bonding. The only time you'd need to bond in this situation is if any of the internal metal pipe was in contact with the "outside world" (eg if a length of metal pipework was run in the ground to an outside tap)

Is this right?

Every time the subject comes up I end up more confused!

 

[Richard Burns]

Plastic incoming pipe, no possibility of introducing a potential, so no bonding. The only time you'd need to bond in this situation is if any of the internal metal pipe was in contact with the "outside world" (eg if a length of metal pipework was run in the ground to an outside tap)

Is this right?

Every time the subject comes up I end up more confused!

Internal metal pipes where the main incomer is plastic could be come "earthy" for a variety of reasons, the pipes could be embedded in the structure of an old wall and damp in the wall allows an earth potential, your example of a pipe running underground is also possible, it maybe just run in the concrete of a floor internally, if the pipework at a boiler connects (possibly through the boiler metalwork) with an incoming "earthy" gas pipe, if part of the plumbing system is connected to the earthing arrangement via CPCs connected to the metalwork this will make them "earthy" but not sufficiently well connected for bonding (really!!whatever), even pipes clipped with metal clips screwed into a (usually external) wall can cause an earth potential.

Test by measuring the continuity to the main earth terminal.

 

[Engineer54]

Internal metal pipes where the main incomer is plastic could be come "earthy" for a variety of reasons, the pipes could be embedded in the structure of an old wall and damp in the wall allows an earth potential, your example of a pipe running underground is also possible, it maybe just run in the concrete of a floor internally, if the pipework at a boiler connects (possibly through the boiler metalwork) with an incoming "earthy" gas pipe, if part of the plumbing system is connected to the earthing arrangement via CPCs connected to the metalwork this will make them "earthy" but not sufficiently well connected for bonding (really!!whatever), even pipes clipped with metal clips screwed into a (usually external) wall can cause an earth potential.

Test by measuring the continuity to the main earth terminal.

Absolutely correct Richard!!

Had a big argument on this very subject not so long ago on here. Just because the incoming service has been replaced with plastic doesn't necessarily mean that the existing metal pipework within the building isn't capable of carrying a potential, from flat to flat and beyond, for all the reasons you have highlighted above. The older the building, the more likely you will find via testing, that the existing internal metal services will be far, far lower than the magic 23K ohms and will indeed need bonding.

People also scoff at internal metal staircase railings being capable of carrying a potential in concrete framed buildings. Bet if they actually checked/tested them, over 90% would warrant a case of being bonded, (They will generally be welded direct to the stair re-bar reinforcement) not that i normally would, ....not unless there was a significant risk, with say a buildings electrical incoming supply system or whatever, being in in close proximity!!! lol!!