I see it a lot where the SWA isn’t serving as a protective conductor which I know it must still be earthed at one end due to being an exposed conductive part. My question is if multiple SWAs are all earthed at the supply end and meet again at a bit of equipment if we then connect all the SWAs together locally is this still classed as earthing even though they are already earthed at the supply? 
MrJack96, I don't think that you have much to worry about in your electrical career because you ask some interesting questions.
It cannot be earthing (CPCs) because those cables clearly do not provide a path back to earth. They appear to be an attempt at supplementary bonding, but presumably the exposed conductive parts are electrically continuous at the supply end.
It looks a bit like plumber's bonding to me - a waste of copper.
well if you are not sure if a green/yellow wire is earthing or bonding, ask what happens if you cut that link ?
1~) would you remove the CPC - the return path for operating the ADS. if the ADS would be disabled, that is a CPC or earthing.
2) would you only remove a conductor that keeps the touch voltage down during a fault but does not remove the ADS - this is bonding,
Of course it could be both or neither.
Mike.
It cannot be earthing (CPCs) because those cables clearly do not provide a path back to earth.
That is clearly not true, as current due to a fault in one of the cables will be carried back down another cable. The armour acts as "conductors in parallel".
presumably the exposed conductive parts are electrically continuous at the supply end.
OK, but isn't that how the copper conductor is used when it is provided in parallel with armour?
The SWA must be earthed somewhere - making it a (Circuit) Protective Conductor - so I'm not sure it can ever be classed as an exposed-conductive-part.
I disagree with this. If a core in the cable is used as a cpc, then the armour is only an extraneous exposed-conductive-part. It can be earthed at one end only (usually the "source" end).
edited to correct typo.
I presume you are not proposing that the armour may sometimes be left totally unearthed.
Therefore when earthed it acts as a CPC for the internal circuit in case of, for example, striking by a spade.
How can it be an extraneous-conductive-part? Extraneous-c-ps are not earthed.
Even if it were, it would then have to be bonded which would have the same result as an earth - not the purpose of bonding.
Mr.Jack would be more correct in his thinking of it as an exposed-c-p which has to be earthed so we are back to square one - earthing and a CPC.
I am just posting at the bottom of the list of replies.
The armouring of any S.W.A. cable can't be an exposed-conductive-part cos it ain't exposed to touch. It is covered with insulation. But it definitely does need to be properly glanded and earthed at it's origin. (And at its load end as well in most cases).
Also, the S.W.A. is not an extraneous-conductive-part as it forms part of the electrical installation. (See definitions)
I would say that the conductive steel wire armouring is more accurately described as a circuit protective conductor. I often use it with two core cable as such.
Z.
The armouring of any S.W.A. cable can't be an exposed-conductive-part cos it ain't exposed to touch.
I feel the the wording of the definition sometimes isn't always helpful. If a part can be made hazardous live by a fault, can't be directly touched because of something around it, but that something doesn't provide sufficient insulation to make the situation safe, then it seems to me there is a problem. Cable sheaths are generally not considered to be adequate for insulation. It's a similar situation with flush steel back boxes surrounded by plasterwork (and 'live wall' consequences). I suppose you could consider the SWA and plastic sheath, or back box and plasterwork, together as one exposed-conductive-part to fit the definition, but that's hardly intuitively obvious.
- Andy.
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