18th Edition Bonding requirements

[mattg4321]

Was talking about this with a couple of guys on site earlier and differing opinions were had. It seems the line quoted below has introduced some confusion.

"Metallic pipes entering the building having an insulating section at their point of entry need not be connected to the protective equipotential bonding (Regulation 411.3.1.2)."

Example 1. Some were of the thinking that for example an incoming iron water pipe that somewhere just above floor level had say a metre of plastic pipework before continuing in copper would never need bonding as it has an insulating section. Some were of the thinking you should test the pipework above and/or below the insulating section to see if it is extraneous.

Example 2. Some were of the thinking that any utility supply service that enters the building in plastic will never need bonding and some thought the internal pipework should be tested to see if it is extraneous.

What say you forum? I have my own thoughts I shall keep to myself for now...

 

[Harry_P]

Was talking about this with a couple of guys on site earlier and differing opinions were had. It seems the line quoted below has introduced some confusion.

"Metallic pipes entering the building having an insulating section at their point of entry need not be connected to the protective equipotential bonding (Regulation 411.3.1.2)."

Example 1. Some were of the thinking that for example an incoming iron water pipe that somewhere just above floor level had say a metre of plastic pipework before continuing in copper would never need bonding as it has an insulating section. Some were of the thinking you should test the pipework above and/or below the insulating section to see if it is extraneous.

Example 2. Some were of the thinking that any utility supply service that enters the building in plastic will never need bonding and some thought the internal pipework should be tested to see if it is extraneous.

What say you forum? I have my own thoughts I shall keep to myself for now...

I think its another case of people making something complicated when it could be so simple. I interpret that reg as 'if the metallic pipes entering the building have gone into plastic pipe at the point of entry then it is pointless bonding because the electrical connection wont get past the plasic because plastic is not a good conductor of electricity.
Ps , is the extraneous pipe 'liable to introduce a potential '? Definitely not if it's subsequently gone into plastic

 

[Deleted member 26818]

This is not an 18th edition bonding requirement.
This is just an explanation of what everyone should have been doing all along.

 

[mattg4321]

This is not an 18th edition bonding requirement.
This is just an explanation of what everyone should have been doing all along.

You try telling that to a meter fitter when you haven't bonded anything!

Also, it has changed things slightly in that you would still be required to bond the incoming iron pipework where it enters the property below the insulating section in 17th edition regs.

Are you in agreement that if there is an insulating section there is NEVER a need to bond and no need for any testing then?

 

[Harry_P]

You try telling that to a meter fitter when you haven't bonded anything!

Also, it has changed things slightly in that you would still be required to bond the incoming iron pipework where it enters the property below the insulating section in 17th edition regs.

Are you in agreement that if there is an insulating section there is NEVER a need to bond and no need for any testing then?

To be fair I would only explain it to a meter fitter if he was paying me to do the job,otherwise he would be told to worry about his own job and leave me to worry about mine. The only time I get involved in debates about electrics with non electricians is if it's with the bill payer and I am on day rate,then I don't mind talking all day

 

[johnduffell]

insulating section at their point of entry

it has changed things slightly in that you would still be required to bond the incoming iron pipework where it enters the property below the insulating section in 17th edition regs.

if there's a metal pipe below, then the insulating section isn't at the point of entry. I'm sure everyone has their limits on how far from the point of entry is close enough, but if the water supply comes in 6 inches of metal at elbow height next to the washing machine on a TN-C-S that's a bit different from 5 metres of lead pipe lying in the dirt under the suspended floor on a TT. Use common sense I suppose.
Personally I just think the clarification is to wastage of copper by people who don't know what extraneous is.

Some were of the thinking you should test the pipework above and/or below the insulating section to see if it is extraneous.

you should test anything that may be extraneous same as always, not just the common services. this reg doesn't do anything special

how about if you have incoming in plastic then goes around the house in copper and tees off to an outbuilding underground still in copper. You'd test after the insulating section and discover it appears to be extraneous, but the incoming water supply still doesn't need bonding, but the outgoing supply to the shed does. so bonding the incoming supply after the insulating section would be non compliant with the regs.

 

[Nigel]

You try telling that to a meter fitter when you haven't bonded anything!

Also, it has changed things slightly in that you would still be required to bond the incoming iron pipework where it enters the property below the insulating section in 17th edition regs.

Are you in agreement that if there is an insulating section there is NEVER a need to bond and no need for any testing then?

No as this insulating section would then be after the point of entry and therfor the pipe before the insulating section would need bonding.

 

[Wilko]

Many new supplies have plastic for gas and water, but that hasn't stopped folks from bonding the copper on the house side of the meter. I'm thinking it's not breaking the regs to bond in this case and it may prevent future issues. But always happy to learn .

 

[Ian1981]

Many new supplies have plastic for gas and water, but that hasn't stopped folks from bonding the copper on the house side of the meter. I'm thinking it's not breaking the regs to bond in this case and it may prevent future issues. But always happy to learn .

You should limit any pipe work that’s connected to earth that doesn’t need to be as it introduces a potential that need never had existed.
Gas pipes will be connected to earth via the cpc connecting to the boiler manifold anyway but unnecessary pipe work bonded should be avoided

 

[Flanders]

The key word is insulating section not insulated section , water can still carry electricity so I would always test to confirm if it needs bonding.

 

[Ian1981]

The key word is insulating section not insulated section , water can still carry electricity so I would always test to confirm if it needs bonding.

Water is actually a poor conductor of electricity
In this instance I would go with what bs 7671 tells us about this particular subject.

 

[Flanders]

Water is actually a poor conductor of electricity
In this instance I would go with what bs 7671 tells us about this particular subject.

Yes I agree with that but if the plastic part was very short for example a plastic coupler the electric could slip through , I think there is a calculation for this.

 

[Midwest]

You should limit any pipe work that’s connected to earth that doesn’t need to be as it introduces a potential that need never had existed.
Gas pipes will be connected to earth via the cpc connecting to the boiler manifold anyway but unnecessary pipe work bonded should be avoided

Personally I can't see any change in the old gambit, if its metal bond it approach.

I've moved into a new build, and both services are plastic. Haven't verified whats happened to the water, but the gas has been bonded, although the copper pipe goes from the meter box 4m to the boiler in the garage. Large domestic house basher, who must have loads of HNC etc etc designers/engineers with more initials after their name than Phil the Greek, but still have the bond it approach.

 

[Ian1981]

Personally I can't see any change in the old gambit, if its metal bond it approach.

I've moved into a new build, and both services are plastic. Haven't verified whats happened to the water, but the gas has been bonded, although the copper pipe goes from the meter box 4m to the boiler in the garage. Large domestic house basher, who must have loads of HNC etc etc designers/engineers with more initials after their name than Phil the Greek, but still have the bond it approach.

I’ve done the old 500v IR test approach onto the piece of metal(gas) and the MET on my new build.
Got a reading of around 15-20Mohms.

 

[Wilko]

I’ve done the old 500v IR test approach onto the piece of metal(gas) and the MET on my new build. Got a reading of around 15-20Mohms.

Hi - how can this be?
To your point earlier - shouldn't the boiler itself be earthed and gas pipework after the meter is copper ... (?)