Equipotential bonding

[EddieB]

Guys
I'm about to change a Cu and the bonding cables are 6mm, I know they need to be 10mm but the unit is under the stairs in the centre of the house, the floor above is laminated, in other words I have no way of getting the bonding cables re-sized without destroying half the floor upstairs,Can I leave them in but add them to the limitations of the work

 

[welsh spark]

What earthing system is it m8 if memory serves me right you can have 6mm bonds on a tt sysem or at least you could on the 16th prehaps someone can clarify this. If not a tt then they have to be 10mm ive come across this many times its a pain

 

[saveloy]

Have to agree with Welsh spark. Your cu change won't meet regs if 10mm is required. Also there are no limitations on an EIC but only on a PIR. Even if you did log it on an EIC, you are admitting that the installation does not meet standards, which could leave you open to prosecution should anything go wrong!!

 

[flukey]

Guys
I'm about to change a Cu and the bonding cables are 6mm, I know they need to be 10mm but the unit is under the stairs in the centre of the house, the floor above is laminated, in other words I have no way of getting the bonding cables re-sized without destroying half the floor upstairs,Can I leave them in but add them to the limitations of the work

sounds like all the jobs ive had lately all my runs have been a pain in the **** must be due an easy one soon where the gas and water are close up wth the laminate me thinks

 

[Guest123]

At th'end ot day, if them cables be too small then theys gotta be replaced.

Rulez is rulez.

 

[Steve1412]

Am sure it won't be long before we have wireless bonding...

 

[johnnyb]

Agree with all the above, sounds like they must be upgraded to 10mm mate.

 

[andekoch]

I thought that if the main equipotential were 6mm or greater that could remain but anything less needs to be changed. The departure is then noted on the EIC. Also make sure you state that you are only instaling the CU. At least that way you have stated your limit of responsibility and also made the customer aware that the bonding needs upgrading.

 

[diditrain]

I was under the impression that if it was a TN-S system then you could do the adiabatic equation to see if they were adequate

 

[scotsparky]

diditrain the adiobatic is for the Main earthing conductor only not the main bonding conductors.

 

[ezzzekiel]

If you are carrying out maintenance or replacement​

of damaged equipment there is

​

​

no need to bring Main​

Equipotential Bonding (MEB) Conductors up to the

current regulation requirements, although if you can,
you should bring them up to the current standards, if
you can do so with your customer’s agreement.
If you are carrying out modifications or additions to a
circuit or system on either the TN-S or the TT
configuration, then you have three options.
Either you bring the MEB Conductors up to the
current requirements outlined in 547-02-01; or, having
ensured that the MEB Conductor is at least 6mm2,
advise your customer that the MEB Conductors do not
meet current regulations (that is if they don’t) and seek

their permission to upgrade them (at their cost, not your
cost), if that permission is not forthcoming. Then note
on the electrical certificate, that the MEB is 6mm2 and​

permission was not granted to upgrade them.

​

​

​

Napit guidelines.

 

[c.boy]

i agree with nthe 10mm!!! but just out o argument sake lol!!!!! if you can get your resistance result below 0.05 ohms ,protect all circuits with rcbos then all would be good???? a dont make the rules!!!but regs are not a must!!!!! just a guideline!!!! they are not law!!!!!!

 

[diditrain]

Thank`s scotsparky. They say everyday is a day at school and today i have well and truly learned.
Many thank`s

 

[saveloy]

i agree with nthe 10mm!!! but just out o argument sake lol!!!!! if you can get your resistance result below 0.05 ohms ,protect all circuits with rcbos then all would be good???? a dont make the rules!!!but regs are not a must!!!!! just a guideline!!!! they are not law!!!!!!

The regs may not be the law, however you would have to prove that any design that was installed without using BS7671 regs was safe. Fine if you are a qualified designer but very hard I would have thought for a lot of us.
Because BS7671 is non statutory then you cannot be prosecuted for not complying with the regs. However you could be prosecuted under the EAWR which is statutory law. In the abscence of comprehensive design criteria the only defence for you to prove a safe installation, is to follow BS7671, and prove you have followed it.

As a warning, a mate of mine (NIC approved contractor) was called out to a job, by a plumber, about a month ago. It was an older property with suspect wiring (old rubber IIRC).
The plumber was originally called out because the owner had boiling water coming out of the mains cold tap in the kitchen. Being fairly clued up the plumber put a clamp meter around the mains pipe to the tap. There was 40 AMPS!! being put through the mains pipe from the dodgy wiring. It was heating the water to boiling point!!
Guess what? being an older property there was no Equipotential Bonding.Thank god the plumber knew what he was doing and didn't touch the pipework.

Brought home the importance of ME bonding to me!!

 

[scotsparky]

i agree with nthe 10mm!!! but just out o argument sake lol!!!!! if you can get your resistance result below 0.05 ohms ,protect all circuits with rcbos then all would be good???? a dont make the rules!!!but regs are not a must!!!!! just a guideline!!!! they are not law!!!!!!

Yes you are right the regs are a non statutary document.

However the Electricity at work ACT is and it does say in there ( arround chapter 6 i think)if you comply with BS7671 then you will comply with the ACT.

Therefore due to that wording if you do end up infront of a man in a wig you have to prove you complyed with the current BS7671 therfore complying with the Electricity at work Act and so complying with the Health and Safety Act. If you cant you may have a "Bunkie called Bubba who likes a late night cuddle"