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Combi bonding


L-E_Fault

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I was told by an electrician that this bonding is no longer required if the water and gas is bonded where it comes in to the property. Which is news to me, what do you lot think?

I realise the bonding is cut also which is bad practise? Bonding done by the gas fitter.

Tim

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Lets not confuse bonding with supplimentary bonding!

Think it's been said before, it's not an electrical reg but a gas one.

AFAIK it's only main bonds that shouldn't have joints.

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Those are very untidy supplementary bonds and in my humble opinion bad practice to cut the cable when bonding multiple pipes. The right way would have been to use a stanley knife to strip the insulation and expose an inch of copper for each pipe clamp and wrap it around each bonding clamp on the middle pipes with the pipes on the extreme sides crimped and nice neat loops of equal size between. The safety tags would also be positioned to cover the connection.

If all circuits are RCD protected and all earthing and incoming services correct size and correctly connected/ bonded then the installation is seen as using ADS as it's method of protection against electric shock. Supplementary bonding is only needed when the above criteria are not met in which case EEBADS would be applied.

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no need to main bond a boiler, unless at the points of entry for the gas (oil ect) or water, or it is at this point where these services first turn into copper pipework.

no need to supplementary bond a boiler unless it is in a bathroom and supplementary bonding is required in that bathroom.

i did work for someone once, who would bond under the boiler in 10mm2, if there was no main bond to one service in an attempt to get a low ohm reading on the pipework if the unbonded service. I myself will not do this.

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I was told by an electrician that this bonding is no longer required if the water and gas is bonded where it comes in to the property. Which is news to me, what do you lot think?

I realise the bonding is cut also which is bad practise? Bonding done by the gas fitter.

Tim

Supplementary bonds should never be cut. As I understand it 16th Edition supp bonding is required, 17th CU supp bonding not required as supplementary protection is by RCD.

I do occasionally take main bond to boilers and cross bond pipes where access to traditional main bond points is difficult.

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Have been told by various gas fitters that cross bonding the pipes at the boiler is no longer required.

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Page 31 On-Site-Guide....

4.6 Additional protection - supplementary equipotentail bonding.

Supplementary equipotential bonding is required in some of the locations and installations or Part7 of BS7671.

If the installation meets the requirements for earthing and bonding, there is no specific requirement in BS7671 for supplementary bonding of:

  • Kitchen pipes, sinks or draining boards.
  • Metallic boiler pipework.
  • Metal furniture in kitchens.
  • Metallic pipes to wash hand basins & WC's.
  • Locations containing a bath or shower, providing the requirements o 701.415.2 are met.

Note metallic waste pipes in contact with earth must be bonded to the main earth terminal as they are extraneous conductive parts.

gives the guidance I believe...:);)

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Page 31 On-Site-Guide....

4.6 Additional protection - supplementary equipotentail bonding.

gives the guidance I believe...:);)

That is of course based on RCD everything - or am I stating the obvious :coat

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So if the circuits are RCD protected and the gas and water are mains bonded where they come into the property then theres no need to bond at the boiler.

If theres no RCD protection and the gas and water are bonded on the incoming the boiler pipes need to be bonded.

Am I right so far?

If there is no mains bonding or RCD would you need to run an un-cut earth to the MET?

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Under the regulations, a simple continuity test has been applicable since conception.

There is absolutly no need to supplementary bond providing conditions are met as per the post by Special Location(which is excellent by the way).

I would agree that like all regulations they are open to interpretation, however, simple use of testing and knowledge can and will help in any situation.

Extraneous conductive parts, must under the regulations always be bonded.

The reason for this is that they go to earth, Tn, so the potential difference could be higher or lower than the installation Tn.

This could cause a problem under any fault conditions in that one potential is so much greater than the other that an electric shock could occur if you where to touch one, and be in contact or proximity to another.

Bonding will equalize the potential, so touching one part, will have a similar effect when touching both parts, as the potential difference is negated to zero, or as near to.

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So if the circuits are RCD protected and the gas and water are mains bonded where they come into the property then theres no need to bond at the boiler.

If theres no RCD protection and the gas and water are bonded on the incoming the boiler pipes need to be bonded.

If there was no RCD protection...

It could reasonably be assumed that the system was installed under earlier regs and would thus have to have complied with EEBADS thus be already supplementary bonded;)

Am I right so far?

If there is no mains bonding or RCD would you need to run an un-cut earth to the MET?

There has GOT to be MAIN BONDING! reg 131.8 whether RCD or not.

The bit to be aware of is that note..

If your heating pipes are Extraneous, and could introduce another earth potential onto the system then you do need a main bond back to MET from that pipework that goes into the ground.

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Ah.. Gh has been a postin while I was a composin.. and off visitin the kitchen!:P:^O

:x

LOL I always steal your valuable advise!!!

Whilst your in your kitchen, I could smell the cheese on toast and the warm smell of a coffee.

So I knew you would be busy, and jumped right in:^O

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LOL I always steal your valuable advise!!!

Whilst your in your kitchen, I could smell the cheese on toast and the warm smell of a coffee.

So I knew you would be busy, and jumped right in:^O

bit late for coffee. I could murder a toasted tea cake...............

:D

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AFAIK supp bonding of the boiler pipework never was an IEE reg (per se) but a CORGI requirement. Stems from the days when electrical continuity between the various pipes could not be guaranteed. All boilers now are designed to have electrical continuity between all pipe connections where the pipes meet the boiler, and thus the CORGI requirement for supp bonds was dropped a few years ago.

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bit late for coffee. I could murder a toasted tea cake...............

:D

watchit_cop.gif

cctv1.jpg

watch out plods about your being watched :^O:coat

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