Cable armor as grounding conductor?

[joj]

Hi Everyone,

I?m currently working here in Saudi Arabia as an Elec. Engr. where the standards being used are a mixture of both British and American standards.

My problem is one of the contractor here in the project will be using a 4core CU/XLPE/ PVC/ SWA(steel wire armor) cable for the low voltage system. For the circuit protective conductor or grounding conductor, they are proposing to use the steel wire armor of the cable.

I?ve read some forums that using SWA as CPC is allowed in British standards. However there are also some restrictions as regard to using the steel wire as a substitute for the separate CPC or grounding conductor.

Is there any particular article in NEC codes or British codes were using SWA is not allowed as CPC? If so can somebody lend me a copy?

Appreciate your help on this matter.

 

[infinity]

I would guess that the closest thing in the NEC would be MC cable which is covered in Article 330 which you can read here:

http://www.nfpa.org/aboutthecodes/AboutTheCodes.asp?DocNum=70

 

[petersonra]

I don't recall SWA being a NEC wiring method. If so, there would be no guidance to be found there.

 

[suemarkp]

http://en.wikipedia.org/wiki/Steel_Wire_Armoured_(SWA)_Cable

 

[joj]

I don't recall SWA being a NEC wiring method. If so, there would be no guidance to be found there.

I think so Bob, I've been reading the NEC but I could not find SWA as wiring method.

 

[lixinglong]

Hi Everyone,

I?m currently working here in Saudi Arabia as an Elec. Engr. where the standards being used are a mixture of both British and American standards.

My problem is one of the contractor here in the project will be using a 4core CU/XLPE/ PVC/ SWA(steel wire armor) cable for the low voltage system. For the circuit protective conductor or grounding conductor, they are proposing to use the steel wire armor of the cable.

I?ve read some forums that using SWA as CPC is allowed in British standards. However there are also some restrictions as regard to using the steel wire as a substitute for the separate CPC or grounding conductor.

Is there any particular article in NEC codes or British codes were using SWA is not allowed as CPC? If so can somebody lend me a copy?

Appreciate your help on this matter.

As per BS7671(2008 Revision), the use of the armouring of a cable is permitted.
Pls check page 131 in BS7671.

 

[lixinglong]

NEC (NFPA 70:2011) provides some requirements for armored cable. When you check Article 320, the code asks you to see 250.4(A)(5) or 250.4(B)(4).
I think NEC dosen't oppose using the armring of the calbe as CPc, but you should check the sectiong area to assure it can endure the earth grouding fault current.