New house, no main water bonding

[ash_s3]

Just been to a new house (5 years old) which had no main equipotential bonding to the incoming water. Gas was bonded with 10.0mm
Checked on original EIC and water service box was marked N/A
All pipe work inside the house is copper but the supply pipe is plastic up to main stop tap

Surely this isn't right?

 

[trev]

Correct, it is not right, the internal metal pipework should be bonded.
There's an unless figure but I can't remember what it is

 

[rich.250]

23000 ohms.

 

[trev]

I thought 22k but wasn't sure cheers Rich

 

[ash_s3]

I though it needs bonding unless ALL internal pipe work is plastic.
Might see if neighbors houses are the same.
I assumed there would be no issues with this property with it being so new.
Dual rcd board - check
gas bond - check
water bond - err... It must be here somewhere!

 

[rich.250]

Only need to bond a parallel path. Could be a section in plastic, best bet is to test it. If its over 23 000 doesn't require bonding.

 

[Richard Burns]

From OSG "There is no requirement to main bond and incoming service where the incoming service pipe and the pipework in the installation are both of plastic. where there is a plastic incoming service and a metal installation within a premises main bonding is recommended unless it is confirmed that any metal pipework within the building is not introducing an earth potential."

IF an IR test between MEt and the metal pipework give a value <22Kohm then the metal internal pipework should be bonded, if it is greater than that then there is no need to bond as it is not introducing an earth potential.

There is some variation in the IR figure depending on who you listen to but generally if it is not connected to earth then there is not need to bond plastic incomers.

 

[J&M Electrical]

So am i right in thinking that if the main feed, stop tap and (for arguments sake) 1st 6m of consumers pipe is plastic, but the rest is copper you bond your main bonding as soon as it changes to copper?

I have never actually worked on a property like that before so its new to me.

 

[trev]

Unless there's more than 22k ohms IR that's about the size of it

 

[ash_s3]

Right, so pipe work needs to be >22,000 ohms. Is this IR test carried out at 500v?

 

[rich.250]

I would carry out a continuity test. And if over 23k ohms then it does not need bonding. Taking this from a 'safe' touch current of 10mA.
230\0.01= 23,000 ohms

My opinion of the OSG is proving to be more true each time I hear stuff from it. I don't like it to say the least.

Yes if it's all plastic and you can see it is. Then it's pointless testing.
But if there's any copper id check as its your --- on the line if it ain't right.

 

[rich.250]

Continuity test.

 

[ash_s3]

Well it's all copper so needs testing.
Entire plumbing install is copper right up to the supply pipe.

 

[rich.250]

Yeh best get the tester out.

 

[ash_s3]

Will my tester test up to that value? Megger 1553

 

[rich.250]

From OSG "There is no requirement to main bond and incoming service where the incoming service pipe and the pipework in the installation are both of plastic. where there is a plastic incoming service and a metal installation within a premises main bonding is recommended unless it is confirmed that any metal pipework within the building is not introducing an earth potential."

IF an IR test between MEt and the metal pipework give a value <22Kohm then the metal internal pipework should be bonded, if it is greater than that then there is no need to bond as it is not introducing an earth potential.

There is some variation in the IR figure depending on who you listen to but generally if it is not connected to earth then there is not need to bond plastic incomers.

Surely an IR test is not the best idea. Introducing unnecessary voltage onto pipe work. Especially if the house is occupied and they are home.

Also the figure depends on the current that is deemed to be safe to touch. 30mA is the max. But most people like to work off 10mA to be on the safe side.
Plus 1000ohms for the resistance of the body.

 

[rich.250]

My 1730 will. I think yours will. What's the max on the cont setting when you turn it on??

 

[ash_s3]

Was going to say! Best make sure they're not in the bath/washing up when doing the test!

 

[Darkwood]

if the property has combi boiler its highly likely unless insulated joints to need bonding as the gas, combi supply earth and water will all be connected together.

 

[ash_s3]

Think it's 99.9Kohms actually

 

[ash_s3]

Yes there is a combi boiler. Will surely need bonding then

 

[rich.250]

if the property has combi boiler its highly likely unless insulated joints to need bonding as the gas, combi supply earth and water will all be connected together.

Good point darkwood. That would certainly bring it down lol.

 

[Guitarist]

Bottom line, bond water unless ALL pipework is plastic. You can argue figures till you're blue in the face but if anything went wrong the question would be "Why wasn't the water main bonded?"

 

[Darkwood]

And agreeing with Guitarist here what happens if the resistance changes in the near future and a fault occurs ?? always best to bond regardless if all copper install.

 

[rich.250]

True true. But if it's over you are just introducing an unnecessary component into the bonding.
I'd rather test it and know I'm doing it right at least. Every install is different.
Just bonding stuff is not a good idea in my eyes and many more.
Each to there own method.

 

[ash_s3]

So why wasn't this picked up earlier?
I'd imagine whole site is the same (50+properties)

 

[rich.250]

I think you'll find that some installers just don't care. Anything to save time and earn more unfortunately.

 

[Darkwood]

True true. But if it's over you are just introducing an unnecessary component into the bonding.
I'd rather test it and know I'm doing it right at least. Every install is different.
Just bonding stuff is not a good idea in my eyes and many more.
Each to there own method.

This could be a generation thing and was how we were taught, although the theory hasn't changed the industry has and RCD's now allow different teaching methods regarding bonding as installations are alot safer... in my day if you said rcd you'd wander what it meant.

 

[rich.250]

Yeh I do agree. If its entirely copper then more than likely it needs it.
Do you see what I mean though, if people are taught to test and see then people would know what needs it and doesn't.
Otherwise we could see people bonding
Anything metal just in case......
And that's just wrong

 

[Guitarist]

True true. But if it's over you are just introducing an unnecessary component into the bonding.
I'd rather test it and know I'm doing it right at least. Every install is different.
Just bonding stuff is not a good idea in my eyes and many more.
Each to there own method.

I understand where you are coming from rich, but if someone has a combi-boiler installed later on, you will get some cross-bonding. If you bond the main properly then the water component won't be a problem whatever happens in the future.

 

[tonycoysh]

Our house is less than 2 years old. Gas is bonded in 10mm, no bonding to water. Although the original EIC issued indicates there is bonding to Gas AND Water added to this there is 2 bonding 10mm cables in the CU one definitely goes to Gas (visual and continuity) to this day I haven't found the end of the other 10mm. The water main comes in under the sink in plastic, changes to copper to sink taps and washer and dish washer taps, combi etc then there is plastic to go up stairs to 2 x bathrooms and to airing cupboard with a pressurised hot water system, as well as a downstairs toilet. All change back to copper for the last couple of foot before taps. Heating system is all plastic direct to the rads.

 

[Guitarist]

Yeh I do agree. If its entirely copper then more than likely it needs it.
Do you see what I mean though, if people are taught to test and see then people would know what needs it and doesn't.
Otherwise we could see people bonding
Anything metal just in case......
And that's just wrong

And no, I'm not an advocate of the "bond anything metal" mentallity :mellow:

 

[Darkwood]

we are commented on OP situation here where he has all copper install plastic incomming and yes i do understand about the testing part and getting ppl to understand when and where but regarding the OP situe id have bonded it regardless of reading, if it was part mixture copper and plastic throughout then id go by the result of the resistance test and see if it likely to remain that way in hindsight.

 

[trev]

Do you see what I mean though, if people are taught to test and see then people would know what needs it and doesn't.

As an apprentice I was taught how to test an installation (Although it took a while for me to understand the whys and wherefores) because, in Bill's words, any self respecting spark should be able to prove his work is safe. I completely agree with that.
Nowadays sadly it seems to happen more and more that sparks will say I don't know how to test or what the results mean and this is on all types of installation. It makes me bloody annoyed, how can you call yourself a spark if you cannot completely finish the job by testing it and filling in the cert, or find a fault

 

[rich.250]

Totally agree trev

 

[Darkwood]

Gotta agree their Trev .... my theory is a monkey can pick a cable size by rule of thumb but an electrician can explain indepth to why its done that way and what the test results stand for, both will walk of site feeling like they know what their doing but only the monkey is kidding himself.

 

[jumpin jax]

Going back to the op, if there was an earth potential being brought in it would be from the gas incomer which is bonded, if there is an immersion heater the pipework would have a connection through the cpc of the heater element, i believe also that if IR tested and the reading between the MET and the pipework is less than 0.05 ohms and the water incomer is plastic then there is no need to bond as a good connection is present. If the water incomer was metal then bond it as, in the future, the gas could be brought in as plastic and the bonding disconnected.