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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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  • 0
    But do the cable manufacturer's instructions say anything about Earthing the armour? I don't recall ever seeing such a thing. I've seen things like 'Should not be installed at temperatures below 0OC or above +60°C' or 'should be installed according to national wiring rules'.


    I'd suspect the manufacturers would want to avoid such detailed instructions such as the need to Earth things - partly to avoid any liability (better to pass the buck onto JPEL/64) and partly not to want to unnecessarily rule their products out from the more unusual situations (e.g. separated systems, d.c. PV or SELV).


      - Andy.
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  • 0
    But do the cable manufacturer's instructions say anything about Earthing the armour? I don't recall ever seeing such a thing. I've seen things like 'Should not be installed at temperatures below 0OC or above +60°C' or 'should be installed according to national wiring rules'.


    I'd suspect the manufacturers would want to avoid such detailed instructions such as the need to Earth things - partly to avoid any liability (better to pass the buck onto JPEL/64) and partly not to want to unnecessarily rule their products out from the more unusual situations (e.g. separated systems, d.c. PV or SELV).


      - Andy.
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