Understanding the new regulation regarding Main Bonding.

[HappyHippyDad]

Regulation 411.3.1.2 states ....

Main bonding conductors shall connect to the main earthing terminal extraneous conductive parts.

It then goes on to say...

'Metallic pipes entering the building having an insulating section at their point of entry need not be connected to the protective equipotential bonding'.

Lets say we have a water pipe coming into the house in the plastic blue pipe, from then on its metal. The above reg makes me believe this does not need Main bonding, is that correct?

The above reg does not suggest we test the water pipe to see if it extraneous. It just says we have to bond extraneous parts, then it says not to bond if they come in to the house in an insulating section.

If we do test the water pipe it is likely that it will test at 1 or 2 ohms to earth (probably as it is usually connected to earth somewhere within the premises). Does this reg still imply not to bond in this case when we can clearly see an insulating section at point of entry?

 

[GBDamo]

That's how I read it.

plastic coming in, all plastic pipe work = no bond
plastic coming in, all metallic pipe work = no bond
metal coming in, immediately to plastic or a section of = no bond
metal coming in, immediately metallic pipework = bond

This doesn't however mean that pipework that enters in plastic doesn't at some point revert to metal and then creates an extraneous path which may or may not need bonding.

hope that clears it up for you.

 

[cliffed]

Agree,don’t seem right though,for us older sparkies.

 

[littlespark]

Just bond it... even if it is plastic

 

[Empire]

As you have mentioned already, measure resistance to MET from metallic pipework. <22Kohms = bond.

 

[Charlie_]

Same with oil pipes, there’re usually insulated and then we bond at a concealed section.
Incoming Gas pipes are usually insulated
How will a section of insulation stop it from being extraneous??

 

[cliffed]

Same with oil pipes, there’re usually insulated and then we bond at a concealed section.
Incoming Gas pipes are usually insulated
How will a section of insulation stop it from being extraneous??

Exactly,who makes these regs,plastic makes it not extraneous.

 

[GBDamo]

Just bond it... even if it is plastic

Must bond, must bond, must bond. Pointless bonding pictures. - https://www.electriciansforums.co.uk/threads/must-bond-must-bond-must-bond-pointless-bonding-pictures.173496/

your handywork then?

 

[ChrisElectrical88]

As you have mentioned already, measure resistance to MET from metallic pipework. <22Kohms = bond.

Exactly this, belts and braces this way and your not just seeing a section of plastic and saying no bond. Obviously make sure parellel patha are disconnected first.

Made a post about a month ago on this when i was undecided. Metal coming in streight onto a plastic section then back to metal after the stoptap to the rest of the house. Didnt bond it as the IR reading from the MET to consumer side of the stoptap was around 30k.

 

[buzzlightyear]

That's how I read it.

plastic coming in, all plastic pipe work = no bond
plastic coming in, all metallic pipe work = no bond
metal coming in, immediately to plastic or a section of = no bond
metal coming in, immediately metallic pipework = bond

This doesn't however mean that pipework that enters in plastic doesn't at some point revert to metal and then creates an extraneous path which may or may not need bonding.

hope that clears it up for you.

I'm glad some one cleared that up thanks Geronimo

 

[Rpa07]

I'm glad some one cleared that up thanks Geronimo

I don’t think I’d like to be the one taking that photo - he seems a little miffed!

 

[buzzlightyear]

I don’t think I’d like to be the one taking that photo - he seems a little miffed!

he must have had bad hair day.

 

[Rpa07]

he must have had bad hair day.

May have been mistaken for his grandmother!

 

[Pete999]

No mate he had an Apache on his head, and ut wasn't his own hair never had Head and Shoulders in those days.

 

[GBDamo]

I'm glad some one cleared that up thanks Geronimo

I'm sure if you look closely you can see his peace pipe

 

[Deleted member 9648]

As you have mentioned already, measure resistance to MET from metallic pipework. <22Kohms = bond.

Obviously make sure parellel patha are disconnected first.

It's almost impossible to eliminate parallel paths, if there's a combi for example the gas service will be mechanically joined to the water pipes. The test for extraneousness (I just made that word up) is generally unreliable and I prefer to combine it with a visual assessment of how likely a water pipe is to become extraneous when entirely within a building. Unless the building is steel framed the likelihood is minimal.

 

[buzzlightyear]

No mate he had an Apache on his head, and ut wasn't his own hair never had Head and Shoulders in those days

no prisoners for that man .

 

[GBDamo]

It's almost impossible to eliminate parallel paths, if there's a combi for example the gas service will be mechanically joined to the water pipes. The test for extraneousness (I just made that word up) is generally unreliable and I prefer to combine it with a visual assessment of how likely a water pipe is to become extraneous when entirely within a building. Unless the building is steel framed the likelihood is minimal.

Especially in a 32nd floor flat!!

 

[ChrisElectrical88]

It's almost impossible to eliminate parallel paths, if there's a combi for example the gas service will be mechanically joined to the water pipes. The test for extraneousness (I just made that word up) is generally unreliable and I prefer to combine it with a visual assessment of how likely a water pipe is to become extraneous when entirely within a building. Unless the building is steel framed the likelihood is minimal.

I had the on site plumber take a small section out right after the stop tap so i could test it which eliminated all parellel paths lol. Serched everywhere are there was no other extraneous parts. I thibk the reason i got 30KOhms was resistance through the wat or i would have had greater than 99MOhms

 

[The Ghost]

Ever since I started electrics back in 1961 bonding/equipotential cross bonding extraneous metal has been it seems a dark art. With a myriad of opinions on it most wrong. And an almost superstitious "...if it's metal bond it!.." approach. I think in this case it is simpler than we may overthink it is. One caution though, I have been in houses that start with plastic to copper. The copper wends its way through the property to the back bath and or kitchen but goes sub floor in cement so in such a case...??? It is only that there is not one rule fits all a careful survey needs to be done to be sure bonding is not needed as @wirepuller said "...a careful visual inspection..." is required.