No bonding on new build

[PC Electrics]

What was the resistance between any metal pipework & earth prior to you putting a bond on?

Specs, this was quoted as 20Mohm earlier in the thread.

Interesting answer from the builder though:

they don't bond it because it's a plastic supply pipe

NOT

they didn't bond it because it was tested at 20Mohm to MET and therefore didn't need bonding.

Subtle difference in approach, which could lead to the wrong answer in some circumstances.

 

[Andy™]

iirc, you dont bond if its over 22K ohms to MET, not 20M ohms

 

[Nicky Tesla]

I Would not bother to bond thats my opinion, its not introducing the earth. Simples

 

[batty]

I Would not bother to bond thats my opinion, its not introducing the earth. Simples

So you don't work to 7671 as far as I am aware a copper pipe installation needs a main bond.

 

[wozz]

[quote name='Andy

 

[PC Electrics]

[quote name='Andy

 

[green-hornet]

I will give my answer on this, and it is based on my personal views.

Any main supply to a building in the last 20 years or so has been made in plastic.

With the 16th edition we were told to bond at the incomming supply, normally where the stop tap is.

Back then all pipe work in the building was done in copper, and it made sense to bond.

Then later on came the all plastic installations, many of which included a length of about 6 inches of copper so that the electricians could bond to comply with regulations.

Now we have full plastic installations where the only copper will be at the taps, and a 1m length at the boiler.

If the installation is all done in copper then main bond it!

If its all in plastic then do not.

If the installation is all in copper then the water WILL be earthed at some point in the system probably and more favorite at the boiler, with a main bond at supply this will help maintain under any fault, a relative equal potential.

Gas supplies are almost always made in plastic now, with all interior pipework done in metal/copper.

I doubt a potential exists but it would be mad not to bond to gas now would it.

So with that in mind if its all plastic dont main bond.

If its all copper(with plasic intake) then main bond.

Any faults that are likely to make all the pipe work become live really does need to be bonded to earth for safetys sake.

 

[batty]

I will give my answer on this, and it is based on my personal views.Any main supply to a building in the last 20 years or so has been made in plastic.

With the 16th edition we were told to bond at the incomming supply, normally where the stop tap is.

Back then all pipe work in the building was done in copper, and it made sense to bond.

Then later on came the all plastic installations, many of which included a length of about 6 inches of copper so that the electricians could bond to comply with regulations.

Now we have full plastic installations where the only copper will be at the taps, and a 1m length at the boiler.

If the installation is all done in copper then main bond it!

If its all in plastic then do not.

If the installation is all in copper then the water WILL be earthed at some point in the system probably and more favorite at the boiler, with a main bond at supply this will help maintain under any fault, a relative equal potential.

Gas supplies are almost always made in plastic now, with all interior pipework done in metal/copper.

I doubt a potential exists but it would be mad not to bond to gas now would it.

So with that in mind if its all plastic dont main bond.

If its all copper(with plasic intake) then main bond.

Any faults that are likely to make all the pipe work become live really does need to be bonded to earth for safetys sake.

This is what I was told on a new build I did last year. Pipework was plastic apart from gas so only gas was bonded.

 

[PBC_1966]

So you don't work to 7671 as far as I am aware a copper pipe installation needs a main bond.

And in my book too. It's been required for decades, regardless of whether the supply line to the property is metallic or plastic. Running around bonding 6-inch lengths of copper between plastic push-fit couplings is a pointless exercise, but where the entire internal installation is copper, it should be bonded.

 

[ianmacd]

Running around bonding 6-inch lengths of copper between plastic push-fit couplings is a pointless exercise, but where the entire internal installation is copper, it should be bonded.

What about the eletrolytic solution running though the pipes? Shouldn't this again come down to the resistance to Earth of that piece of pipe?

 

[Andy™]

So you don't work to 7671 as far as I am aware a copper pipe installation needs a main bond.

if the feed is plastic, it cannot be extraneous, therefore does not require an earth. the pipework inside being plastic or copper makes no difference, but in some cases, the pipe can be extraneous from contact with ground at a different point

 

[Andy™]

And in my book too. It's been required for decades, regardless of whether the supply line to the property is metallic or plastic. Running around bonding 6-inch lengths of copper between plastic push-fit couplings is a pointless exercise, but where the entire internal installation is copper, it should be bonded.

its never been required for decades.

if the feed is metallic, then a voltage can be intorducated into the property. if its plastic, then a voltage cannot be introduced into the property. hence plastic is not extraneous, and does not require an earth.

same with the gas - wont need bonded if its plastic feed.

 

[PBC_1966]

[quote name='Andy

 

[Andy™]

been chanced at some point. i dont have any regs before 16th to look back to

 

[batty]

[quote name='Andy

 

[Nicky Tesla]

pasted from above

"I don't think you understand the reason for bonding metal pipes. Imagine a cable comes into contact with a pipe under the floor just the phase conductor. Now all the metal pipework and possibly kitchen sink and even metal bath will now be a 240 volt potential"

1.What if a cable passed through a window reveal to an outside light, but the window was metal and the live conductor made contact. The window would be live, but who bonds windows

2.What if cable snags on the metal Tbar in a suspended ceiling the whole grid would be live, but are we supposed to bong the grid. No.

Just throwing a spanner in the works;\

 

[Andy™]

I don't think you understand the reason for bonding metal pipes. Imagine a cable comes into contact with a pipe under the floor just the phase conductor. Now all the metal pipework and possibly kitchen sink and even metal bath will now be a 240 volt potential. Water main is plastic so pipes have no return to earth. Anybody touching a metal part of the installation will take a full 240 volt through there body and if it was a tiled floor in kitchen that could be the end of them. If pipes had been bonded to main earth terminal then that circuit would be disconnected. I am seriously worried about the work you are doing if you think metal pipes do not need bonding.Batty

im guessing you bond everything, including the nail on the cable clip, just incase, even though there is no requirement for it?

 

[batty]

[quote name='Andy

 

[Andy™]

Now you are just being a little childish. I will carry on bonding metal pipework as stated in regs you will not but thats your option in life just hope nobody on your jobs comes to regret the fact.

please state which regs say it must be bonded regardless of being plastic feed or not

 

[batty]

[quote name='Andy