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-   -   Is Grounding using Armored Cable ok? (http://www.diychatroom.com/f18/grounding-using-armored-cable-ok-85194/)

pankaek 10-29-2010 10:49 AM

Is Grounding using Armored Cable ok?
 
1 Attachment(s)
I know this has been posted before but I've read conflicting reports as to what is ok by NEC.

My house was re-wired with 2-wire armored cable (wired in 1993) so this is not the old armored cable people talk about. I'm assuming armored cable was used because of nails etc. behind the walls.

I've re-wired the 2 prong non grounded outlets with 3 prong grounded outlets. The ground wire is firmly attached to the ground screw on the receptacle and firmly attached to the metal box. The armored cable is firmly clamped to the metal box as well. Ground tests show 110V between the hot and ground and nothing between the neutral and ground.
Is it acceptable to ground outlets like this according to NEC?

What are my other options here? Ideally I'd like to have all properly grounded outlets in the house.
Attached is a photo of the 2-wire armored cable.

Thanks

Mike

nap 10-29-2010 11:07 AM

Is there a small bare conductor within the metal sheath? If not, you cannot use the sheath as an egc. It's just that simple.


If there is no small bare conductor inside the sheath, yes, that is the old AC (colloquially: BX) cable that everybody talks about.

pankaek 10-29-2010 11:28 AM

1 Attachment(s)
Yes, there's a bare metal wire (see attached photo) from one of the wires I pulled out from the house.
I'm still a bit paranoid that maybe not all the armored cable has this bare wire so I should probably double check every single outlet that's rewired. Also I'm wondering why the electricians didn't originally put in grounded outlets back in 1993.

nap 10-29-2010 12:12 PM

that is the revised AC cable and the sheath is wholly acceptable as an egc. That is the improvement that came from the problems with the original AC (BX) cable.

If you have doubts to the modern AC, it surely wouldn't hurt to check.

Why they didn't install grounded outlets in 1993? No idea. They were required in all new installations at that time.

pankaek 10-29-2010 12:44 PM

Thanks Nap,

appreciate the help. I'm guessing the previous owner had the house rewired but was too cheap to buy new grounded outlets and possibly kept the old ones that were there. I've also replaced all the old light fittings that were in very poor condition and had badly corroded wires. Seems counter productive to redo the wiring but keep the old fittings and outlets.

The joys of an old house!

nap 10-29-2010 04:51 PM

I always tell people to put the money in the walls rather than something that is easily changed. Changing receps is easy. Running that stuff in the wall, now, is a bear.


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