Earthed SWA

[New2Game]

Does the armoured bit of SWA that is clipped direct to a wall have to be earthed?

 

[Lectrician]

Yes.

 

[New2Game]

Why would it need to be earthed if it can be clearly seen? TW&E is not earthed if clipped direct

 

[Lectrician]

Why use armour?

 

[ColJack]

twin and earth had better be earthed whether clipped or not..

SWA is for mechanical protection and must be earthed..

likewise metal conduit..

 

[the_pasty]

Even if one of the cores is used as an earth does the metal sheath still need to be earthed?

 

[bernardgreen]

YES.

 

[Steve]

The point of SWA is to protect anyone unlucky enough to strike it and / or cut through it with a metal implement. On cutting through it, whichever core you hit first will short to the earthed sheath. When the live shorts to the sheath, the supply is disconnected. Its not guaranteed to short straight away without the earthed sheath.

 

[davy_owen_88]

I think the point the OP is making, is that if there is no requirement for mechanical protection, but you chose to use SWA anyway, does the sheath still need earthing. I'd be inclined to say no, as long as a separate core was used as earth, but I'm not sure on this as I wouldn't bother using SWA unless it was required.

 

[Spark123]

The armouring is single insulated hence can only be used for a CPC etc. As it is a conductor in the construction of the cable it should not be left floating and hence should be connected to earth.
I can't remember ever installing an SWA without earthing at least one end.

 

[plugwash]

leaving stuff that is designated eath (whether the earth core of T&E or the armor of SWA) floating is very bad practice, apart from the fact that it protects in the event of cable damage someone could eailly rely on it as the earth for something (say metal boxes used to extend the cable in order to re-route it out of the way of a new doorway) later.

 

[securespark]

It is best practice to earth it. Why would you NOT want to?

Do you want to terminate it without glands?

If that SWA then goes underground then the armour MUST MUST MUST be earthed.

 

[New2Game]

Wanted to terminate without glands as knockouts are not 25mm, only 20mm or 32mm

 

[passerv]

What size SWA are you using?

Just use a reducer from 32 to 25. IMHO Swa cable without glands is really sloppy.

 

[RF Lighting]

Or drill out a 20mm knockout to 25mm