Swa armour earthing

[keniff]

Can anyone point me in the right direction as to find the size of conductor to earth the armour of swa? It's not being used as the cpc on the circuit it's 25mm 3core. I'm always trying to find this when I'm terminating armoured cable!! Thanks

 

[Inteificio]

look at the stickies

 

[Moses]

Can anyone point me in the right direction as to find the size of conductor to earth the armour of swa? It's not being used as the cpc on the circuit it's 25mm 3core. I'm always trying to find this when I'm terminating armoured cable!! Thanks

10mm for 25mm Neutral, if not used as an earth.

 

[rich.250]

http://www.electriciansforums.net/e...ulations/23288-can-we-use-armour-swa-cpc.html

 

[Moses]

http://www.electriciansforums.net/e...ulations/23288-can-we-use-armour-swa-cpc.html

Yes, but you need to make sure that the equivalent of the armour CSA, in copper CSA is what you need it to be.

 

[rich.250]

Is that not in the table?? or am i having a blonde moment here... lol

 

[keniff]

Thanks for the links, I don't want to use the armour as the earth I mean the size of the flyleads to earth the different sizes of cable.....

 

[Moses]

Is that not in the table?? or am i having a blonde moment here... lol

I think you are having a blond moment.

its not in the table.

You need the manufacturers tables.

 

[rich.250]

Im blaming the beer....
I'm sure it says steel c/a and equiv. in copper...
if not my bad

 

[i=p/u]

your right as for fly leads id say same csa as line conductor

 

[Engineer54]

Yes, but you need to make sure that the equivalent of the armour CSA, in copper CSA is what you need it to be.

Why would you need to know that ??? I can understand if you were using the armour as a combined CPC/Bonding conductor, but not purely for use as a CPC....

 

[Engineer54]

Thanks for the links, I don't want to use the armour as the earth I mean the size of the flyleads to earth the different sizes of cable.....

So what is this armour and fly lead doing then, ...If not that circuits CPC??? Have you by any chance run in a separate single CPC conductor along side the SWA cable??

Just to let you know, a 25mm 3 core SWA cables armour, is more than capable of acting as that cables CPC!! lol!!!

 

[telectrix]

from what i can gather from the OP, he's asking what size conductor should be used to earth the armour when the armour is NOT being used as cpc. i always try and use the same size as the cpc.up to 10mm. i.e. if it's a 6mm 3 core cable. i would use a 6mm fly lead to earth the armour of the SWA. ( assuming it's glanded into an insulated enclosure)

 

[Engineer54]

from what i can gather from the OP, he's asking what size conductor should be used to earth the armour when the armour is NOT being used as cpc. i always try and use the same size as the cpc.up to 10mm. i.e. if it's a 6mm 3 core cable. i would use a 6mm fly lead to earth the armour of the SWA. ( assuming it's glanded into an insulated enclosure)

Exactly, and effectively causing the armour to become a CPC if both ends are connected to say the MET at origin and EMT or other earthing terminal at the load end... Whether he has run a separate earthing conductor (CPC) or not!!

 

[telectrix]

agreed, the armour will become cpc ( or part thereof ) if connected at the downstream end, but not if it is only earthed at the source end to comply with being an earthed metallic sheath.