New CU Bonding upgrade.

[junior-sparky]

Hi All,

If you were to install a new CU in a property and it had 6mm bonding or even no bonding at all can you make the property owner install bonding. I understand that if it has 6mm and it's showing no signs of degrading that it's ok but can you install a new cu without if the customer says NO

http://www.niceic.com/Uploads/File1950.pdf

link above says -

"4.1. There is no legal requirement that calls for anexisting electrical installation to be upgraded to
current standards."

what is everyone's opinion

 

[SPARTYKUS]

You can't 'make' anyone do anything in their house. Its their house.

 

[Spoon]

Have a quick search of this. There is loads of stuff on bonding when installing a new CU here.

 

[telectrix]

what's the eartrhing system. ?

 

[junior-sparky]

I had a quick sear but so may topics and thought it would be easier to ask.

It's a TNS system

 

[Andy78]

4.1 in that sense is referring to the fact that there is no requirement for a customer to upgrade their consumer unit on the basis of age or non compliance with current regs.

From the same ESC guide a bit further down, pertaining to earthing and bonding when a CU is to be swapped.

6.1. The installer must verify, as a minimum, that:
a) the main earthing terminal of the installation is
connected to an adequate means of earthing
via a suitably sized earthing conductor,
b) the main protective bonding is adequate, and
c) the meter tails and the distributor’s equipment
have adequate current-carrying capacity.

6.2. If any of conditions 6.1 (a), (b) or (c) is not met, the
customer should be informed that upgrading is
required. If the customer refuses, the installer
should not proceed with the replacement of the
consumer unit.

 

[junior-sparky]

I would of thought that it would be against regs if you did not install any bonding inside when installing a new CU. I guess you just explain the risks of potential shock "don't touch 2 connected items at a time" LOL

 

[junior-sparky]

4.1 in that sense is referring to the fact that there is no requirement for a customer to upgrade their consumer unit on the basis of age or non compliance with current regs.

From the same ESC guide a bit further down, pertaining to earthing and bonding when a CU is to be swapped.

6.1. The installer must verify, as a minimum, that:
a) the main earthing terminal of the installation is
connected to an adequate means of earthing
via a suitably sized earthing conductor,
b) the main protective bonding is adequate, and
c) the meter tails and the distributor’s equipment
have adequate current-carrying capacity.

6.2. If any of conditions 6.1 (a), (b) or (c) is not met, the
customer should be informed that upgrading is
required. If the customer refuses, the installer
should not proceed with the replacement of the
consumer unit.

So as long as all earthing from DNO side is good, bonding to gas water etc can not be done if the customer refuses, just explain risks and note on the cert?

 

[telectrix]

just as he says^^^^^^^.you could calculate the min. size for main earthing conductor using adiabatic, . as it's TN-S, then then the main bonding needs to be 50% or more of that value. as long as there's no sign of damage and you test the bonding for continuity and secure connection, then the 6mm can stay.

 

[Andy78]

So as long as all earthing from DNO side is good, bonding to gas water etc can not be done if the customer refuses, just explain risks and note on the cert?

The main bonding conductors must be in place and adequate for the system otherwise you are not to carry out any work.
Reg 132.16

 

[junior-sparky]

just as he says^^^^^^^.you could calculate the min. size for main earthing conductor using adiabatic, . as it's TN-S, then then the main bonding needs to be 50% or more of that value. as long as there's no sign of damage and you test the bonding for continuity and secure connection, then the 6mm can stay.

Just to confirm that if they agree to upgrade main earthing to 16mm but not upgrade or even install equipotential bonding explain risks if he/she does not and note on cert/departures

 

[Andy78]

Just to confirm that if they agree to upgrade main earthing to 16mm but not upgrade or even install equipotential bonding explain risks if he/she does not and note on cert/departures

NO. You must provide adequate main bonding if none is present. If you proceed to alter the electrical system without main bonding in place you are not working to the regs.
If the customer refuses the bonding work, you walk away.

If existing bonding is present but of a smaller size than required by current regs, then follow Tel's advice. As a rule of thumb existing 6mm is generally ok.

 

[junior-sparky]

cheers people some of us were quite confused yesterday in class with what you can/can't do.

 

[JulianC]

Ludicrous isn't it really? Hypothetical and not entirely unrealistic scenario: customer has a clapped out, potentially dangerous consumer unit that could spontaneously combust at any moment and no bonding. You breeze in and quote for snazzy new consumer unit, bristling with RCDs, and bonding. Customer refuses bonding installation despite your best efforts to advise them to the contrary. You walk away, leaving them with a potential fire hazard because 'the regs' don't allow you to make one part of an installation safe without first upgrading another. Just saying like....

 

[telectrix]

exactly. as long as you can show that the 6mm is in place and is of adequate size to cope with prospective fault currents, you're OK> otherwise upgrade or walk.