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surface-mounted SWA – earthing

Former Community Member
Former Community Member
Just trying to find a regulation that states a reason why the armoured metal of surface-mounted SWA needs earthing. Obviously, when buried underground, it does - 522.8.10.  I have read previous posts on this, but the question seems to have remained unanswered.

It would be considered best practice to at least earth the supply end, but best practice is not regulation. And, considering the statement at the end of Chapter 12, could it not be argued that short runs of surface-mounted armoured without earthing are ‘safe’? Where is the risk?

The armour does not meet the definition of an exposed conductive part when neatly terminated so it can not be touched – under what fault conditions could it become live?

SWA conductors are not double insulated, but is the risk any less than conductors in a plastic conduit?

Manufacturer instructions… it could be that they stipulate that the armour needs to be earthed, but where these are not available for review, how can a non-conformity be raised?

I’d appreciate any replies that point to a specific regulation or group of regulations.

Thanks in advance.

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    You don't have to actively put a nail in it - you could be tie-wrapping an SWA to a tray that has a burr sticking up, or cleating to a wooden post that happens to to have the tip of a nail pointing out, etc. And because it's an SWA, its not just the nail that becomes live, its the entire length of armour - and especially its two ends - which are now live. Are the ends of the armour completely sealed off in a way such that even a skilled person opening an enclosure couldn't make contact with them? (Because who treats a bit of exposed armour as dangerous?).


    But please read the whole of the previous thread - in short, its not obvious whether the armour counts as an exp-c-p
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    You don't have to actively put a nail in it - you could be tie-wrapping an SWA to a tray that has a burr sticking up, or cleating to a wooden post that happens to to have the tip of a nail pointing out, etc. And because it's an SWA, its not just the nail that becomes live, its the entire length of armour - and especially its two ends - which are now live. Are the ends of the armour completely sealed off in a way such that even a skilled person opening an enclosure couldn't make contact with them? (Because who treats a bit of exposed armour as dangerous?).


    But please read the whole of the previous thread - in short, its not obvious whether the armour counts as an exp-c-p
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