4mm Supplementary Bonding for new kitchen install??

[Deleted member 26818]

There are only two conditions for metallic parts in any building. Are they guaranteed permanently isolated from other earths as proved by inspection? If they are then no need to earth. If not they should be permanently earthed via tested and visible connections to ensure same potential difference and disconnection times of devices.

Thats why it matters.

There was me thinking that only extraneous and exposed-conductive-parts required bonding/earthing.

 

[oxocube]

I agree, what happens to your central heating pipes that are touching an extraneous conductive part? I'll tell you, your central heating pipes are an now extraneous condutive part.

 

[Deleted member 26818]

I agree, what happens to your central heating pipes that are touching an extraneous conductive part? I'll tell you, your central heating pipes are an now extraneous condutive part.

And if that extraneous-conductive-part that your central heating pipes touch, is bonded/earthed, what does it matter?

 

[oxocube]

Whats the resistance of were they are touching, what happens when the pipe temp changes.

 

[i=p/u]

0.05 or more yah bond it

 

[tony mc]

Hope this does not go like a PME to out building thread as bonding seems to come up quite alot on the forum.

Im reading this getting a little confused with supplementary bonding main bonding and 0.05 ohms.

My understanding is that supplementary bonding is only required under 7671 in special locations if certain conditions are not met.

Then a continuity check between the extraneous and exposed conductive parts should have a minimal deflection of 0.05 ohms or less if the results are higher supplementary bonding is required.

(Edit bit) The 0.05 is the deflection of the supplementary bonding cable. The check between extraneous and exposed parts would be useing the R<50V/Ia formular.
25V & Idn would be used depending on the special location & if a RCD was used.

The kitchen senerio with a metal waste etc would require a IR test between the MET and the suspect piece of metal and a reading of below 22k then this would require main bonding with the correct csa cable etc.

Hope that makes sense.

 

[Voltimax]

Bonding of kitchen sinks was rife under the 15th edition in the 80's. When the 16th edition came out, bonding in kitchens was scrapped and sink manufacturers were well aware of this, because before the early 90's all metal sinks came with a big earth lug on them. About 1991 or 92, sink manufacturers stopped making them with earthing lugs. Nowadays it's rare to find a sink with an earthing lug.

 

[Deleted member 26818]

I seem to remember that it was also the fashion to bond Crittle windows as well.

 

[Voltimax]

Under 15th edition if it was metal it got bonded

My nick name as an apprentice was 'Tenby King'

 

[Deleted member 9648]

There are only two conditions for metallic parts in any building. Are they guaranteed permanently isolated from other earths as proved by inspection? If they are then no need to earth. If not they should be permanently earthed via tested and visible connections to ensure same potential difference and disconnection times of devices.

Thats why it matters.

I give up:banghead:

 

[Deleted member 26818]

Place I used to live in, had an immersion heater, that was also plumbed up to back boiler in an open fire.
Should the open fire have been bonded?

 

[Deleted member 9648]

Place I used to live in, had an immersion heater, that was also plumbed up to back boiler in an open fire.
Should the open fire have been bonded?

Earthed?....Bonded?.....or maybe earthed and bonded just to be sure.

 

[oxocube]

I give up:banghead:

I agree, you should give up, or give an intelligent response.

 

[Deleted member 9648]

I agree, you should give up, or give an intelligent response.

I've given up because myself and others have explained the differences between earthing and bonding,and the reasons and requirements for bonding dozens of times on this forum. I'm constantly left open mouthed by the number of apparently qualified and experienced electrical people on here who simply dont understand bonding.
Now I'd be the first to put my hands up and admit I dont know everything,and I've learnt loads from the top guys on this forum....but bonding? surely that is a basic principle that all should understand.

 

[malcolmsanford]

I've given up because myself and others have explained the differences between earthing and bonding,and the reasons and requirements for bonding dozens of times on this forum. I'm constantly left open mouthed by the number of apparently qualified and experienced electrical people on here who simply dont understand bonding.
Now I'd be the first to put my hands up and admit I dont know everything,and I've learnt loads from the top guys on this forum....but bonding? surely that is a basic principle that all should understand.

WP you have the patience of one of these, I gave up on this a week ago