Bonding gas/water yellow and blue

[Midwest]

Lets also hope the earth rod & AFFD's also bite the dust, which some have suggested has.

 

[Deleted member 26818]

Can someone reference the reg for testing an extraneous-conductive-part, in the examples given by 411.3.1.2. I only ask that, you would not need to test (those examples), as the reg says they have to be bonded, end of?

There’s no Reg stating you have to test whether something is an extraneous conductive-Part.
There’s no need for one.
If it’s extraneous (i.e. comes into the building from outside), is conductive (i.e. can conduct electricity) and likely to introduce a difference in potential, then it needs bonding.

Determining whether something is extraneous is relatively easy, in the majority of instances you don’t even need to look, you just know.
Gas, water, electricity, cable TV, satalite TV, waste water, telephone, oil, etc. they’re all extraneous.

Determining whether something is a conductive-part however, seems to be problematic.
Plastic coated telephone cables, satellite and cable TV cables along with plastic waste pipes are all deemed as non-conductive.
For some reason, there’s confusion as to whether plastic gas pipes, plastic water pipes and plastic coated oil lines are conductive.
Because of this confusion, a lot of people are advising we test these supplies to determine whether there’s any connection to Earth.
Unfortunately there seems to be various views on what resistances indicate either a reliable connection to Earth or no connection to Earth.
Some say 0.05 Ohms, others say 20 Ohms indicate a reliable connection to Earth.
For whether there’s no connection to Earth the figures for resistance are 23 Mohms or 7.67 Kohms (22 Mohms and 6.67 Kohms when the 1 Mohm resistance of the human body is taken into account).

 

[Midwest]

There’s no Reg stating you have to test whether something is an extraneous conductive-Part.
There’s no need for one.
If it’s extraneous (i.e. comes into the building from outside), is conductive (i.e. can conduct electricity) and likely to introduce a difference in potential, then it needs bonding.

Determining whether something is extraneous is relatively easy, in the majority of instances you don’t even need to look, you just know.
Gas, water, electricity, cable TV, satalite TV, waste water, telephone, oil, etc. they’re all extraneous.

Tis what I've been saying for the best part of this thread. If its metal and comes out of the ground or into a building, then according to 411.3.1.2 it needs bonding. Some are suggesting testing it. Doesn't need testing, just bonding.

My rub is, with the plastic metal combo, unless your building the property yourself, how do you ensure that the metal part of the combo, isn't 'liable' to do the above.

 

[Deleted member 26818]

My rub is, with the plastic metal combo, unless your building the property yourself, how do you ensure that the metal part of the combo, isn't 'liable' to do the above.

Test.

 

[Midwest]

Test.

Why.

 

[Ian1981]

I did some students flats last year.
Plastic incoming water supply to each building then copper pipework.
From copper in the corridors it went to plastic entering each student room.
Showed the apprentice the testing procedure for testing extraneous parts using an insulation resistance tester.
The result was around 20Mohms.
Did I bond any copper pipes?
NOPE!

 

[Deleted member 26818]

Why.

Because, you want to verify that the extraneous conductive-parts are not likely to introduce a difference in potential.
Thus saving you from installing unnecessary bonding which may introduce a potential hazard.

 

[Deleted member 26818]

Here’s a link to an article which may help:
A guide to the determination of extraneous-conductive-parts - https://www.voltimum.co.uk/articles/guide-determination-extraneous

 

[Midwest]

Ok my last swipe at this; you don't test the pipes for 411.3.1.2, 544.1.2 says bond it after plastic.

I think this will just keep going around, until the 18th comes out.

This had an interesting discussion on such testing etc;

Bonding water services when plastic pipes are present - https://www.electriciansforums.co.uk/threads/bonding-water-services-when-plastic-pipes-are-present.61592/

Earthing water. Part plastic, part copper - https://www.electriciansforums.co.uk/threads/earthing-water-part-plastic-part-copper.30881/

 

[Deleted member 26818]

Agree that would make nonsense of the 4mm2 non protected and 2.5mm2 protected rules for supplementary bonding conductors, wouldn't it? Or has that been changed?

Why?

 

[Deleted member 26818]

re spinlondon's post:

The other problem is that the minimum CSA for an Earth conductor buried in the ground and not protected against corrosion by a sheath is 25mm2, 16mm2 if protected.

sureley that's for an earthing conductor, as in connected to a rod., not for a bonding conductor?

Alsways took it as applying to al Earth conductors.
Main earths, bonding, CPCs, etc.

 

[Simonslimline]

no.the 22k ohms is to prove whether or not a piece of copper /metal pipe is extraneous or not.

22k plus 1k for human body.

so 230volts/23K Ohms = 0.01Amps.

GN8 goes in to this.

 

[Deleted member 26818]

Just realised, I’ve been using Mohms instead of Kohms.

 

[Pete999]

Why?

Apologies spin misread the original post, my mistake

 

[Midwest]

Still not convinced.

However, having verified (by testing) that the internal metal pipework was extraneous and required bonding, would you bond it using a main protective bonding conductor or using a supplementary bonding conductor?

 

[Deleted member 26818]

If it’s extraneous, then it would be main bonding.
Supplementary bonding is for special locations and where Zs of a circuit is too high.

 

[Pete999]

If it’s extraneous, then it would be main bonding.
Supplementary bonding is for special locations and where Zs of a circuit is too high.

Thank you spinlondon

 

[mattg4321]

It's not a grey area. If it's an extraneous conductive part it needs bonding. If it's not an extraneous conductive part it doesn't need bonding. I always run a green and yellow in for gas and water on a new builds as I've had muppet meter fitters refusing to connect as no bonding, even though it didn't require bonding. If they moan I connect it then chop it off when the muppet has finished.

The other favourite of theirs is when they tell you the gas isn't bonded and they've only looked at the external meter box. They then insist it should be bonded at the external meter box even though we all know the regs say it should be at the point of entry into the building. Muppets

 

[Pete999]

The other favourite of theirs is when they tell you the gas isn't bonded and they've only looked at the external meter box. They then insist it should be bonded at the external meter box even though we all know the regs say it should be at the point of entry into the building. Muppets

Lets be fair the meter box IS the entry point to the building, albeit external, that's where the Gas and Electricity enter the building, it does in my house.

 

[Ian1981]

Let’s face it if you didn’t bond it at the meter box then the only other logical place is the likes of the boiler as take new builds the pipe enters the house and is buried in the wall.
Then it’s not bonded within 600mm of point of entry.