Zoomup:

Mike, we normally use green and yellow insulated 6491X cables for main and supplementary bonding purposes. It meets all normal requirements for that use to comply with B.S. 7671. In other colours it can be used in metal conduit and trunking, and sometimes in plastic containment as well.

https://www.ukcables.co.uk/cables/6491x



Z.

Mike M:

Zoomup:

Mike, we normally use green and yellow insulated 6491X cables for main and supplementary bonding purposes. It meets all normal requirements for that use to comply with B.S. 7671. In other colours it can be used in metal conduit and trunking, and sometimes in plastic containment as well.

https://www.ukcables.co.uk/cables/6491x



Z.

I do not see how that relates to me wanting to establish which category a single core green/yellow insulated equipotential bonding cables originating from an earth bar and bonding some structural steel work belongs to be it LV, RLV, SELV, PELV, FELV. That gives you 5 possible answers, I'm not sure why you are talking about common uses for 6491X cables.

 

BS7671:2018 mandates different criteria in relation to the voltage category of a cable be it LV, RLV, SELV, PELV, FELV. Before we can review against the relevant criteria we must establish which of these categories a cable belongs to. I am wanting to establish the correct category under BS7671:2018 in relation to a single core green/yellow insulated equipotential bonding cables originating from an earth bar and bonding some structural steel work.

Mike M:

I would say the single core green/yellow insulated equipotential bonding cables are generally considered safe to tough if disconnected at one end as they still provide basic protection as they are insulated but we are getting a bit side tracked here.


 

gkenyon:

Mike M:

I would say the single core green/yellow insulated equipotential bonding cables are generally considered safe to tough if disconnected at one end as they still provide basic protection as they are insulated but we are getting a bit side tracked here.


 

Definitely not getting sidetracked - this is a safety concern. I was talking protective conductors in general - for example, if you disconnect a cpc of a circuit supplying, say, a washing machine from the DB, you might receive a perception-level shock sourced from the noise filter.


However, the same holds true of bonding conductors. Disconnect a bonding cable in some installations, and you might have possibly even Amperes of current flowing through it - parallel paths - again sourced from LV.


Telecomms engineers have occasionally been seriously hurt disconnecting bonding conductors. I was also shown many years ago an article from the far east on a particular case of a telcoms engineer who was killed by removing a bonding conductor whilst carrying out a repair - the recommended approach being to "croc-clip" across it.


Granted in a small installation, such as a dwelling, this may well not be as big an issue, but I would really want to avoid removing bonding conductors if at all possible.


Your premise of the conductor being insulated does not, unfortunately, hold - simply because the terminal or bare end of the wire is not insulated.

 

Mike M:

The reason I said were getting side tracked is because a disconnected protective conductor has no relevance to my original question. People tend to go off on tangents on this forum quite regularly for some reason. I agree where the design requires a bonding conductor to be connected it should not be disconnected i.e. we should not modify the design. However i'm not going to get into a debate as to if having a single core green/yellow insulated equipotential bonding cable disconnected at one end is hazardous to touch as it has no relevance to my original question.