Can you join Main Protective bonding conductor

[bigspark17]

Why are you extending to meter box? Perfectly fine to bond at 1st accessible point into building. If your extending that then you are altering it therefore needs to be 10mm all the way to the MET imo.
I chuckled at your comment "pipework was UPGRADED to plastic" not sure plastic can be considered an upgrade rather than good old solid copper.

 

[Michaelwgroves]

The devil is in the detail, so if you extend an existing bonding cable that becomes new?
Looks like a fine line, I could go either way.

 

[Risteard]

I have a 6mm main protective bonding conductor from a 1981 install; adiabatic equation says this is sufficient and no signs of thermal damage. (Discussed in separate thread).

How have you performed an adiabatic calculation on a cable which isn't there to disconnect any protective device? Main protective bonding is not sized based on adiabatic calculations.

 

[gazdkw82]

So why is it taught in colleges/courses that binding must be 1 continuous length? We covered this again only last week.

 

[Dave OCD]

I think that's the case, it's a bit like if you ran a spur from an older RFC, you wouldn't use 2.5 with the old 1mm CPC, generally any new work which includes alterations or additions must comply with current standards.

 

[westward10]

So why is it taught in colleges/courses that binding must be 1 continuous length? We covered this again only last week.

GN8 demonstrates it should be continuous but it states no Regulation to reinforce this.

 

[gazdkw82]

GN3 not a statutory reg?

 

[Michaelwgroves]

I think that's the case, it's a bit like if you ran a spur from an older RFC, you wouldn't use 2.5 with the old 1mm CPC, generally any new work which includes alterations or additions must comply with current standards.

So are you saying new cable must be 10mm, but I can join to old 6mm?

 

[The Ghost]

GN3 not a statutory reg

No not at all. Statutes are EAWR H&S Act etc. Following regs as noted by EAWR may provide a defense at law when prosecuted under the acts. Not following regs, GN are not regs, could lead to being in a much weaker postion regards defense at law.

 

[westward10]

So are you saying new cable must be 10mm, but I can join to old 6mm?

My opinion you cannot use the 6.0

 

[gazdkw82]

No not at all. Statutes are EAWR H&S Act etc. Following regs as noted by EAWR may provide a defense at law when prosecuted under the acts. Not following regs, GN are not regs, could lead to being in a much weaker postion regards defense at law.

So far as I understand it, not following the wiring regs will mean you are not following one of the above statutory regs and so can be prosecuted. If the "bonding needs to be continuous" practice is neither in the regs nor any of the other statutory regs then we can comfortably forget this and cut as we like

 

[Ian1981]

I need to check underground pipe, school boy error!

Does extending a cable to correct location count as new, or is this existing?
I know TN-C-S is treated different..............

All new work has to comply with current edition of bs 7671 so 10mm is the minimum as you are doing alterations/additional works.
Can be argued that if you say installed a new socket but the existing bonding was in 6mm it could be deemed adequate and left alone,but you intend to install bonding to the gas so must comply with bs 7671

 

[Richard Burns]

So why is it taught in colleges/courses that binding must be 1 continuous length? We covered this again only last week.

GN8 only gives the information that where an equipotential bonding conductor is looped from, say, gas to water services that the conductor should (not must) remain continuous to prevent the chance of disconnection of the water if the gas is disconnected.
This is pure rubbish of course since how likely is it that someone intent on damaging the safety of an installation and ignoring the warning labels will sit there and bother to slowly undo a screw and pull out the cables when they could just cut the conductor in seconds or just remove the clamp entire? However that is only my opinion.
This does mean that in any other case there is no requirement to maintain a continuous conductor and therefore joints are permitted. There are many examples in GN8 where the conductor is not continuous from extraneous conductive part to MET.

 

[Pete999]

Only copper pipe is within 1M of boiler, rest plastic. Water main feed is plastic.

Where it enters the property?

 

[Michaelwgroves]

Where it enters the property?

Plastic