In this case, an undetected fault to armour might leave the armour "live" and wouldn't necessarily be detected by the tests prescribed in BS 7671 (insulation resistance test to cpc or earth won't pick it up) - you'd specifically need to test to armour. What if the outer sheath becomes damaged at some point?
Could the same argument be used with metal clips on ordinary insulated & sheathed cables?
Are we left with the argument that a SWA cable isn't deemed to meet double/reinforced insulation requirements - hence it needs to be protected by ADS (presuming ELV, separation etc options aren't applicable).
I'm starting to think that the exposed-conductive-part concept is getting to be a bit outdated - it might be simpler to think about shock protection the other way around as it were - requiring hazardous live conductors to be surrounded by either additional insulation (section 412) or by a protective-conductive-part (connected to the c.p.c.) to initiate ADS (section 411) (or some combination of the two) (all presuming some alternative method of shock protection - e.g. separation - don't apply).
In this case, an undetected fault to armour might leave the armour "live" and wouldn't necessarily be detected by the tests prescribed in BS 7671 (insulation resistance test to cpc or earth won't pick it up) - you'd specifically need to test to armour. What if the outer sheath becomes damaged at some point?
Could the same argument be used with metal clips on ordinary insulated & sheathed cables?
Are we left with the argument that a SWA cable isn't deemed to meet double/reinforced insulation requirements - hence it needs to be protected by ADS (presuming ELV, separation etc options aren't applicable).
I'm starting to think that the exposed-conductive-part concept is getting to be a bit outdated - it might be simpler to think about shock protection the other way around as it were - requiring hazardous live conductors to be surrounded by either additional insulation (section 412) or by a protective-conductive-part (connected to the c.p.c.) to initiate ADS (section 411) (or some combination of the two) (all presuming some alternative method of shock protection - e.g. separation - don't apply).
