are main bonds required ???

[albi]

i had my niceic inspection one of the jobs was some flats that had been referbed same thing with the gas and water. but he insisted i run the earths to the incoming position just in case of any later alterations. so i would say run the earths in but dont conect them.

 

[electricAl]

What you want is a low earth path creating a very high fault current and so ensuring the overcurrent protective device will blow in time. The ESC and other agree on 0.05 as this will cover a 0.4 disconnection time on a 100a HRC will will be about the largest you will get in a domestic property.

Sorry Scotsparky, but that isn`t the reason that 0.05 ohms is stated as the max permissible resistance between extraneous & exposed conductive parts - which is what is being discussed here. The correct reason was actually given by Markthesparky.
What you`re referring to is applicable where the required disconnection times cannot be achieved by breakers/RCD`s so supplementary bonding is utilised to ensure disconnection within the prescribed times.

Altho the need to ensure adequate conductance is common to both, in the context of Main Protective Bonding to water & gas services, it`s done to ensure no dangerous differences in potential exist between the various conductive parts - achieving equipotentiality.

T

 

[Spudnik]

Explain why the gas WOULD not be in plastic, matey has already said they are in plastic

Have you ever seen a gas pipe in plastic in a house????

equipotentiality.

Al's word of the day

 

[electricAl]

Have you ever seen a gas pipe in plastic in a house????

That was the bit that had me wondering... otherwise, Scotsparky`s spot-on in MHO - don`t introduce it into the installation unnecessarily. Practically tho, never seen plastic internally thru-out

Al's word of the day

Erudite or wot!

 

[scotsparky]

electric my house is plastic pipes troughout apart from the radiators

 

[electricAl]

Sorry mate, was talking about the gas. Could have made it clearer admittedly

 

[chocolate]

Hi all.
Why does water and gas cause a major headache for electricians. Do we deserve this agro ???? The point of all this bonding conductor stuff ( as we already know ) is to cover ourselves from pipework that is exposed to human touch, getting a potential that could be harmful with reference to earth.

Tell me why plumbers aren't made responsible for ensuring their own installation is correctly earthed ?

Do what you can. As long as you can walk away from the site and be confident you've done what you are expected to do, then that's it.

I was told that if incoming pipework was not metallic ( so no conductive path back to earth ), then main bonding wasn't necessary.

But, like you say, what about radiators with a minimal amount of copper pipe work attached ? Well, just like previous wiring regs, which insisted that metallic windows and doors required bonding, things went just too far !!!!!

I would say that radiators fed from plastic pipework don't need bonding. As long as the situation is in writing describing this, then you are ok.

 

[electricAl]

Hi all.
Why does water and gas cause a major headache for electricians. Do we deserve this agro ????

Friday, prior to starting job, checked bonding 10mm & in place...
Gas - no prob.
Water - at what appears to be main stopcock, no bonds in sight...

Upon enquiring, kitchen was fairly recently refurbed. Made a nice neat job of hiding the bond(s) completely behind sink units. Say bond(s) due to how they`d very thoughtfully bonded hot as well as cold (conscientious or what ) but unfortunately placed them in totally inaccessible position, >600mm from incomer & after 2 branches. Classy...

Measured 0.03 ohms.

Thankfully, the peeps at Elecsa are reasonable folk & take these things in their stride... mark down as deviation & carry on

But, like you say, what about radiators with a minimal amount of copper pipe work attached ?

I would say that radiators fed from plastic pipework don't need bonding

Usually not. Whenever in doubt, do IR test between known earth & extraneous part - anything above 20-25k, don`t bond.

 

[WILLRUK]

Evening all,

firstly a huge thanks to everyone for the comments and suggestions - I think this is where this forum and its contributors are at their best.

Secondly, apologies if I've appeared a bit 'mute' on this thread - unfortunately I've been working late this evening and only just got to the PC.

Based on the info I've been given and references from NIC, Paul Cooke etc, I'm sure I don't need to run in main bonds, but after today's experience of the plumber ( same bloke, different job) I'm underwhelmed to put it mildly. Consequently as wisely advised in the thread, I'll run them in anyway just to be on the safe side, even if only for future possible need. Might be overkill, but I'll sleep easier.

Thanks again lads.

 

[chocolate]

Of course, problems may well arise in those special locations ( bathrooms ), where you have to ensire that any exposed conductive parts ( take your pick from piepwork and radiators ) are bonded. So you might have to do some supplementary bonding in those loactions.

 

[sparks1234]

Have you ever seen a gas pipe in plastic in a house????



Al's word of the day

yes I have

 

[Spudnik]

yes I have

Must admit, i never have.

As far as im aware the incomer is plastic and then ALL gas pipes within a property should be copper or galv.

 

[sparks1234]

Must admit, i never have.

As far as im aware the incomer is plastic and then ALL gas pipes within a property should be copper or galv.

There are various conditions that have to be adhered to and installed by certain persons

 

[Spudnik]

There are various conditions that have to be adhered to and installed by certain persons

Fair enough.

Every day is a school day.

Have you got any links or other info on this?

Would be interested to have a read.