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Guest123
Well here is the table to tell you.
Discuss Can we use the armour of an SWA as the CPC??? in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net
Why is it that recently people seem to find using the SWA armour as bad practice or unacceptable. Seems to be serveral posts each week asking if its ok to do.
If running a cable outside, then IMO it is bad practice to use steel armouring as CPC. I have seen numerous times what happens to the armour when the sheath of the cable is damaged, and water starts to ingress. The amouring rots away.
However if you believe that there is no chance of the cable being damaged, or of water ingressing then go for it.
Lenny that is brilliant. I've been looking for something like this for ages, where did you get it.
Check out www.earthingnuts.co.uk
Lenny that is brilliant. I've been looking for something like this for ages, where did you get it.
In reply to Amp David, I think people who don't really know how to make glans off are the ones against it. Yes it's good practice to run a seperate earth but it's not always practical.
cheers, Ron
I think it's poor practice not to use the armour as the cpc when it is adequate to be used as such.
i've been trying to clear this up(for myself)
there is no reason not to parallel the armour and separate cpc is there?-for SP and 3P SWA on PME
thanks
The separate cpc must be sized as if it alone were to take the earth fault current, it is not permissible to add the CSA's of the two conductors together
yes-i know,but otherwise there is no reason why they can't be paralleled is there? on pme
If you are exporting PME earthing out to an outbuilding that HAS extraneous metalwork (=<22000ohms between metalwork and main earth terminal) and you are intending to use the armouring only as an earth conductor then for a:
TNCS system you will need 8 x the required equivalent in copper e.g 10.00 copper required = 80.00mm armouring.
TNS system you will need 4 x the required equivalent in copper.
If after installation it is found to require external CPC it should be a minimum of 25% csa of phase conductor.
"ECA guide to the wiring regs."
Reply to Can we use the armour of an SWA as the CPC??? in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net