6mm acceptable for bonding

[Theorysparky]

My mate told me this week that it is now acceptable not to upgrade bonding from 6mm to 10mm when adding a new cct to an existing consumer unit.

but if upgrading the unit then 10mm is required.

leaving it at 6mm assumes that there is no heat damage or corrosion and that there is good continuity.

He was told this by the NIC and that it is a new change that has recently come into effect

anyone heard of this ???

personally i think it is great

 

[extension15]

My mate told me this week that it is now acceptable not to upgrade bonding from 6mm to 10mm when adding a new cct to an existing consumer unit.but if upgrading the unit then 10mm is required.

leaving it at 6mm assumes that there is no heat damage or corrosion and that there is good continuity.

He was told this by the NIC and that it is a new change that has recently come into effect

anyone heard of this ???

personally i think it is great

So do I, but sadly I haven't heard of it...

(Although I consider 6mm adequate in most cases.. :coat )

 

[Evans Electric]

I heard simlar but can't quote it, Theo.

Specs will know.

 

[ianmacd]

How can you say your work complies with 7671 if you do not upgrade the bonding?

 

[spinlondon]

How can you say your work complies with 7671 if you do not upgrade the bonding?

If your work doesn't involve upgrading the bonding, then you should note on the EIC that the bonding does not comply with current Regs.

You are only required to upgrade the bonding, if it is not adequate for the protective measure applied for the safety of the addition or alteration.

 

[ianmacd]

Yes, but surly you can not state it is adequate if its undersized? If you modify a circuit then you have to ensure that modification is safe so how will you prove that if you are not following 7671?

 

[spinlondon]

I am following BS7671, and my work would comply without upgrading the bonding, because BS7671 requires me to ascertain that the "earthing and bonding requirements are adequate for the protective measure applied for the safety of the addition or alteration."

If your Zs reading is acceptable and there are no signs of over heating or damage to the conductors, then my opinion would be that the bonding is adequate.

If the regulations intended that the earthing and bonding requirements be upgraded, they would not use the term 'are adequate'. They would use the term 'complies with BS7671'.

When issuing an EIC for an addition or alteration, you are required to state the extent of the installation covered by the EIC.

EG. if you are installing a new ring final circuit, then you would state that.

You are further required to sign a decleration that the installation apart from any deviations, complies with BS7671. Any deviations are to be noted in the appropriate section of the EIC.

You are then required to note where reasonably practicable any defects in the existing installation.

 

[PC Electrics]

http://www.esc.org.uk/forum/forum_ed_thread.html

check out question 12.

Ext, I've shown you this link on that 'other' forum some time ago.

 

[Apache]

Welcome PC

To save people clicking

When carrying out electrical work on an installation forming part of a TN-C-S system, is it necessary to upgrade existing 6 mm

 

[binky]

6mm may be acceptable but it isn't good practice, and should be replaced where possible. However, when the water bond is behind numerous kitchen units and through two walls, and customer doesn't want to disturb kitchen it gets examined, left in place, and cert marked accordingly.

 

[tom1]

i thought for pme it is 10mm min and tn-s 6mm only if you have 10mm tails

 

[ianmacd]

Used to be 6mm but in latest its now 10mm.

 

[green-hornet]

I have just done two apartments, each was left with 6mm bonding and was included in my eic for both properties.

The supply for each was 16mm twin and earth with NO additional earthing.

This was also noted on my eic for both properties.

I never upgraded the bonding as it would be fruitless to put 10mm bonding to the water as the properties main earth was smaller!

Each block housed about 15 flats all wired the same.

PME main earthing with recorded Ze @ 0.27

 

[Revved Up Sparky]

I have just done two apartments, each was left with 6mm bonding and was included in my eic for both properties.The supply for each was 16mm twin and earth with NO additional earthing.

This was also noted on my eic for both properties.

I never upgraded the bonding as it would be fruitless to put 10mm bonding to the water as the properties main earth was smaller!

Each block housed about 15 flats all wired the same.

PME main earthing with recorded Ze @ 0.27

But if the incoming tails are 16mm, the earthing conductor should also be 16mm (OSG table 4.1) and thus 10mm MEBC's fitted. Are sparks excused from upgrading 6mm to 10mm if the earthing conductor is less than 16mm then ?. What if the local electrical authority upgraded the main earth the day after you left?. I would be inclined to upgrade the MEBC's anyway as at some point the earthing conductor will be upgraded to the correct size.

Best Regards RUS

 

[green-hornet]

But if the incoming tails are 16mm, the earthing conductor should also be 16mm (OSG table 4.1) and thus 10mm MEBC's fitted. Are sparks excused from upgrading 6mm to 10mm if the earthing conductor is less than 16mm then ?. What if the local electrical authority upgraded the main earth the day after you left?. I would be inclined to upgrade the MEBC's anyway as at some point the earthing conductor will be upgraded to the correct size.Best Regards RUS

The supply cable is a twin and earth, there would be no point in upgrading the bonding from 6mm to 10mm given the fact that under any fault conditions there is no additional advantage or safety increase.

Also you have to take into concideration that whilst any fault that does occur, is there any added advantage in increasing part of the earth cable given the other part is of a lesser sqmm.

Its a bit like a motorway hitting a country lane. The traffic would come to a standstill and a major accident will just be waiting to happen.

All regulations should if practical be followed, however there are deviations, and all installations should not be left in a more dangerous situation than it was hen you carried out the work.

The work I did is actually safer than it was when I started, and all deviations are listed on each eic.

Remember this is a special occasion where given the circumstances of the shared supplies are not to regulations and have been noted and reported to the management council, no electrician should ignore any regulation provided that they make sure the end result is as safe as, or safer than the installation, was when work began.

 

[batty]

The supply cable is a twin and earth, there would be no point in upgrading the bonding from 6mm to 10mm given the fact that under any fault conditions there is no additional advantage or safety increase.Also you have to take into concideration that whilst any fault that does occur, is there any added advantage in increasing part of the earth cable given the other part is of a lesser sqmm.

Its a bit like a motorway hitting a country lane. The traffic would come to a standstill and a major accident will just be waiting to happen.

All regulations should if practical be followed, however there are deviations, and all installations should not be left in a more dangerous situation than it was hen you carried out the work.

The work I did is actually safer than it was when I started, and all deviations are listed on each eic.

Remember this is a special occasion where given the circumstances of the shared supplies are not to regulations and have been noted and reported to the management council, no electrician should ignore any regulation provided that they make sure the end result is as safe as, or safer than the installation, was when work began.

But is the tw/e connected into a 60 amp sw/fuse?

 

[ianmacd]

The supply cable is a twin and earth, there would be no point in upgrading the bonding from 6mm to 10mm given the fact that under any fault conditions there is no additional advantage or safety increase.Also you have to take into concideration that whilst any fault that does occur, is there any added advantage in increasing part of the earth cable given the other part is of a lesser sqmm.

Its a bit like a motorway hitting a country lane. The traffic would come to a standstill and a major accident will just be waiting to happen.

All regulations should if practical be followed, however there are deviations, and all installations should not be left in a more dangerous situation than it was hen you carried out the work.

The work I did is actually safer than it was when I started, and all deviations are listed on each eic.

Remember this is a special occasion where given the circumstances of the shared supplies are not to regulations and have been noted and reported to the management council, no electrician should ignore any regulation provided that they make sure the end result is as safe as, or safer than the installation, was when work began.

While this is true, you can not use 7671 as a defence in law due to any legal action taken against you as you are not compliant with it.

 

[green-hornet]

While this is true, you can not use 7671 as a defence in law due to any legal action taken against you as you are not compliant with it.

I can and will if needed, the requirements have been met and all deviations have been noted on the EIC for each flat.

In fact I am so confident I may use them on my next anual assesment, and see what the assesor has to say about it.

My next assesment is due in November so I will keep you posted.