Elementary dear watson

[cliffed]

External light on remote steel barn,cabled in Swa,supplied from main barn area & switched from there.Does steel barn require Main bonding.

 

[cliffed]

I bet as soon as power is down there an outlet will be put in. So I'd be trying for a small local board and TT.

Exactly,why wouldn’t you Main bond & DB , with TT

 

[johnduffell]

What would happen if a power point was added in the barn?

If it could be used to supply class I equipment or had any exposed conductive parts then you would need to consider adding the surrounding area to the equipotential zone

Exactly,why wouldn’t you Main bond & DB , with TT

Well, you certainly wouldn't do both if you're talking about bonding to the incoming supply, but cost would be the obvious reason. Someone asks for one outside light, they may want the most economical quote so they may have questions if they are quoted for a rod and a db on top of the swa and the light itself.

 

[cliffed]

If it could be used to supply class I equipment or had any exposed conductive parts then you would need to consider adding the surrounding area to the equipotential zone

Well, you certainly wouldn't do both if you're talking about bonding to the incoming supply, but cost would be the obvious reason. Someone asks for one outside light, they may want the most economical quote so they may have questions if they are quoted for a rod and a db on top of the swa and the light itself.

Exactly,but what actually complies

 

[johnduffell]

Exactly,but what actually complies

Well bs7671 isn't statutory anyway despite my earlier flippant comment, but in terms of h&s acts and electricity at work etc which are, you need to look at what's present. In my opinion short of encasing the light in a locked or screwed cabinet with adequate signage you're creating an unacceptable risk if there's any touchable metal with a low resistance to true earth at the same time as the light. Therefore i would personally say it is not safe if that is the case. This would be even more so if the area was used by the general public and was within reach at ground level, and was on a TN-C-S service.
However i have no formal qualifications regarding this topic and i haven't seen the equipment nor tested the metal frame in question.

 

[Wilko]

Exactly,why wouldn’t you Main bond & DB , with TT

Hi All - apologies if I was a bit short on my reply. If I understand correctly, my thought was this is a special location under section 705. And so if ADS is in use TNC is prohibited by regulation 705.411.4, which leads me to TT. Bonding could then be done locally locally to that building's earth terminal, rather than having to take it back to the site cut out. Or have I misunderstood?

 

[telectrix]

What would happen if a power point was added in the barn?

things could be plugged in....the grass would get cut, the dead leaves blown next door, that dreadful leandi would be cut down, the list goes onandonandon.

 

[ipf]

things could be plugged in....the grass would get cut, the dead leaves blown next door, that dreadful leandi would be cut down, the list goes onandonandon.

…...as long as an rcd didn't trip, that is. Mind you...…..?

 

[cliffed]

Hi All - apologies if I was a bit short on my reply. If I understand correctly, my thought was this is a special location under section 705. And so if ADS is in use TNC is prohibited by regulation 705.411.4, which leads me to TT. Bonding could then be done locally locally to that building's earth terminal, rather than having to take it back to the site cut out. Or have I misunderstood?

Agree,I would of preferred a local DB @the said building,then main bonding could take place with the TT system created.
But this is not been done.
My issue is still,I think the steel structure ,barn,should be bonded.