Understanding the new regulation regarding Main Bonding.

[buzzlightyear]

And an almost superstitious

you can sing this when you thinking about it Vort.

 

[TJ Anderson]

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.

Loving Extraneousness!! That should definitely be a word lol

 

[HappyHippyDad]

Some good posts!

I agree, it can be almost impossible to eliminate all parallel paths so an extraneousness test (pinched from @wirepuller ) isn't going to be that reliable.

I think I'll have a chat with my assessor when he comes and see what he says. Until then, I'll flip a coin to see if I'm going to bond!

 

[TJ Anderson]

I don't think it is so hard to determine.

Parallel paths via cpc's will be a low impedance back to MET. You therefore won't know if it was extraneous as you now can't sensibly prove it anymore without disconnecting too much stuff.

If pipework it is at earth potential via a cpc even though it was not extraneous in its own right, you won't do any harm by bonding it, you are just safeguarding if it is truly extraneous.

Most of the sparks at firm I work for don't understand the difference between earthing and bonding lol........let alone making a decision if they should to install it haha

 

[telectrix]

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

he has every right to be miffed, as Sitting Bull and the S0iux took all the credit for wiping out Custard and his blue bellies at Little Big Horn

 

[freddo]

Why are you all still going on about this subject? There is nothing to question as all the answers are already in this book.

 

[snipersmith87]

I thought aslong as it exceeded 7.67k ohms it is not to be considered an extraneous conductive part.

 

[Dave OCD]

Surely if there is an insulated incoming service pipe or even a 3 inch insulating piece between metal incoming and installation pipework then it's impossible for a potential to be introduced from outside the building ? And therefore bonding is not required in such circumstances ?

 

[chrisdungan]

You can't earth plastic end of story. don't be a dick.
Do you earth isolated sections of any sort of pipe.... water/oil etc etc??
My answer is probably not, it's your call.
BUT BUT
I have 2 tests to ask
1 IS IT EXPOSED METAL( OF ANY KIND) THAT HAS THE POTENTIAL TO BECOME ALIVE??????
If yes then the answer must be to earth bond it
2 What would be your defense in the coroners court?

Remember the regs are designed to confuse sparkies by legal numpties.

 

[telectrix]

I thought aslong as it exceeded 7.67k ohms it is not to be considered an extraneous conductive part.

no. the figure is 22K Ohms. 7.67K is the value of a L-E earth fault or leakage that would trip a 30mA RCD.

 

[snipersmith87]

no. the figure is 22K Ohms. 7.67K is the value of a L-E earth fault or leakage that would trip a 30mA RCD.

A guide to the determination of extraneous-conductive-parts - https://www.voltimum.co.uk/articles/guide-determination-extraneous

 

[snipersmith87]

no. the figure is 22K Ohms. 7.67K is the value of a L-E earth fault or leakage that would trip a 30mA RCD.

A guide to the determination of extraneous-conductive-parts - https://www.voltimum.co.uk/articles/guide-determination-extraneous

 

[Deleted member 9648]

You can't earth plastic end of story. don't be a dick.
Do you earth isolated sections of any sort of pipe.... water/oil etc etc??
My answer is probably not, it's your call.
BUT BUT
I have 2 tests to ask
1 IS IT EXPOSED METAL( OF ANY KIND) THAT HAS THE POTENTIAL TO BECOME ALIVE??????
If yes then the answer must be to earth bond it
2 What would be your defense in the coroners court?

Remember the regs are designed to confuse sparkies by legal numpties.

Exposed metal that is likely to become live under fault conditions will be or should be earthed, that is a requirement for an exposed conductive part. That is nothing whatsoever to do with bonding.