Mounting electrical sockets to shed wall

SWA does not need that protection. That's the point of using it.
fair point, but I assumed it was also used because it is more mechanically robust therefore suitable for more harsh environments without degradation or damage. The fact that it's got concentric armour that can be earthed supports your point though, and it was certainly less used in domestic circumstances before RCD protections was a requirement.
 
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SWA does not need that protection. That's the point of using it.
One of the points. I see nothing wrong with 'the cautious' wanting to have RCD/RCBO protection of SWA (ideally, as you say, not sharing an RCD with other circuits) - it's certainly not impossible that damage could occur resulting in enough fault current to trip and RCD, but not enough to trip an OPD. In a TT installation, one obviously has no choice, but I would still want to use SWA for burying (rather than some other cable with an earthed outer 'sheath', if one could find a suitable one), if not only because of its mechanical properties.

Kind Regards, John
 
One of the points. I see nothing wrong with 'the cautious' wanting to have RCD/RCBO protection of SWA (ideally, as you say, not sharing an RCD with other circuits) - it's certainly not impossible that damage could occur resulting in enough fault current to trip and RCD, but not enough to trip an OPD. In a TT installation, one obviously has no choice, but I would still want to use SWA for burying (rather than some other cable with an earthed outer 'sheath', if one could find a suitable one), if not only because of its mechanical properties.
Yes, you probably do (see nothing wrong with being cautious).

Nevertheless, that is why SWA is used - to negate the need for an RCD at the supply end - the same as concealed in walls at <50mm.
If one is to have an RCD at the supply end, then SWA is not necessary.

Plus 'armour' is a misnomer. Once hit by a spade it is damaged even if only the sheath is broken.
 
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Yes, you probably do (see nothing wrong with being cautious). Nevertheless, that is why SWA is used - to negate the need for an RCD at the supply end - the same as concealed in walls at <50mm. If one is to have an RCD at the supply end, then SWA is not necessary.
As I said, that is certainly one reason.
Plus 'armour' is a misnomer. Once hit by a spade it is damaged even if only the sheath is broken.
I'm not so sure about "misnomer", but it is obviously a matter of degree. If one didn't want some degree of mechanical protection, one wouldn't use 'steel wire' armour - a thin copper foil would be adequate to provide an 'earthed covering'. Spades are not the only threat to buried cables - subterranean fauna have been known to have a nibble, and even underground 'movement' could damage a cable with less mechanical strength than SWA.

However, it's all a matter of degree. Furthermore, as we recently discussed at great length, there are very limited alternatives to direct burying in the ground, so, pragmatically, one is likely to be stuck with SWA, even if there are reasons (e.g. a TT installation) why there is (or has to be) upstream RCD protection.

Kind Regards, John
 

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