missing earth clamps in bathroom.new consumer unit fitted.

[davelx]

I wouldn't say it is a different issue as it is one of the requirements for omission of supplementary bonding in a bathroom.

You seem to have slipped that in after I replied! We're just talking semantics (whether or not it is a 'different issue'). As you've implied yourself, there is always a requirement for any extraneous-c-p which enters the premises anywhere to be main bonded - regardless of the considerations relating to supplementary bonding in a bathroom. As far as I am concerned, whether or not one calls that a 'different issue' is really neither here nor there

Kind Regards, John

I'd be interested to know how many premises have their cast iron soil pipe main bonded where it enters the toilet on the first floor through the wall. It would also be interesting to know how it had been done - you can't get 6" diameter bonding straps AFAIK.

 

[JohnW2]

I'd be interested to know how many premises have their cast iron soil pipe main bonded where it enters the toilet on the first floor through the wall. It would also be interesting to know how it had been done - you can't get 6" diameter bonding straps AFAIK.

I doubt that you'd find any - I certainly can't recall having ever seen bonding applied to a metal soil pipe. It's really a situation in which common sense prevails. Although strictly a violation of the equipotential zone if not bonded, the extent to which such pipes enter the property and the (usual) very poor accessibility of what little pipe does enter the building, coupled with the fact that such pipes do not (usually) have electrical continuity with any other conductor means that, in reality, they represent virtually no electrical hazard.

Lead waste pipes serving baths, basins and sinks can be a different matter (if they dive into the earth, or connect to cast iron stacks), and one does sometimes see them bonded. However, such waste pipes very often discharge into a hopper or drain, in which case they do not necessarily qualify as extraneous-c-ps.

Kind Regards, John

 

[davelx]

Yes, my thoughts exactly.

 

[bernardgreen]

I am about to do an insulation resistance check on the large ceramic bowl that feeds the cast iron stack pipe.

But it does make a bit of a mockery when a small water pipe that is plastic outside the house is considered to be a source of dangerous potential yet a 4 inch diameter cast iron pipe can be ignored.

Some plastic gas service pipes once had a metal strip so they would show up on pipe tracing equipment so they could possibly introduce an extraneous potential.

Where did common sense go ?, down that ceramic pan maybe.

 

[davelx]

Interestingly, when our gas mains (~12") were replaced with plastic a few years ago, they replaced all the feeds into the houses by running plastic up inside the existing iron pipes, which were cut back about 18" from the new plastic main.

They used a metal adapter inside the house to connect the new gas meter which maintained continuity of the old iron pipe (so no exposed plastic), which is just buried in the earth but not connected to anything else externally. MPB to the consumer side of the meter clearly required here, of course.

 

[JohnW2]

Where did common sense go ?, down that ceramic pan maybe.

As I said, I think that metal soil pipes are one area where common sense does actually seem to prevail! There's little point in looking to the regs for guidance, since the person(s) who wrote them clearly did not understand the concept of Main Equipotential Bonding!

Kind Regards, John

 

[bernardgreen]

Cast iron stack pipe and conductive "stone" walls ( rubble and mortar ) can make the use of a TT earthing arrangement the better option.

That is my opinion and one shared with a chap who renovates ancient buildings.

Rubble and mortar walls are invariably moist enough to be conductive so they can introduce an extraneous potential ( true ground ) into the building.