I have some 14 gauge "BX" or Armoured cable that I want to use in my Garage
for some more outlets etc. but I am not sure if it is OK to use. Why I am
not sure is that there is no ground wire in it. There is only a black, and a
white wire in it with the paper wrap, then the armoured sheathing. I believe
that the jacket is used as the ground, but I am not sure if that is legal,
I live in Ontario Canada if that matters.
Thanks for any help I may get.
If I had it, I would use it -- with a GFCI upstream. Use the armor for
a ground, and the GFCI will trip if there's a fault.
I don't know for sure if that would be legal, but it is safe and it
should be legal. Without the GFCI there would be a fire risk if there
were a short from hot to ground if it didn't quickly draw enough current
to trip the breaker.
wait till you have to pull out a receptacle to change it
or check it and the steel jacket which you attached
(with great difficulty) to the ground screw breaks off.
and ends up too short to use so you have to pig-tail it.
you'' soon figure out that saving 10 bucks wasn't worth it.
The steel jacket gets clamped to the metal box; the receptacle gets
grounded to the metal box. I don't see a problem (as long as he
protects the circuit with a GFCI, which I said in my previous message
and you trimmed it off.)
first off, i agree, this isnt the place to save 10 bucks and it would
probably be better/easier to use more 'proper' wire. not for safety issues
so much as its going to be a pain in the butt.
however... you simply attach a wire from the green screw on the receptacle
to a green(ground) screw on the metal box.
If this is so, why won't it pass electrical inspection (at least here in
...and I agree, a wire between the box and green screw is fine if the box is
grounded. Not sure if I'd be happy using the sheathing but it would work.
Underwriters Laboratory of Canada has researched this topic and found
that connections to ground of ordinary receptacles using only the
mounting screws are unreliable. That is why they apply an additional
test for grounding continuity to receptacles that they then list as self
grounding. Self grounding receptacles have a spring in the yoke that
maintains contact with the mounting screw. The screws shipped with
those receptacles are plated to resist corrosion.
If you search I-zheet M'drurz other postings you will see he has no
respect for the safety codes of any craft and that includes electricity.
He knows more than everyone else, just ask him and he will tell you
that anyone who disagrees with him is an idiot. But since our man Tom P
says that ULC is full of hooey I guess that settles it. It's your home
friend so you choose which advice you want to follow. It both cases the
advise is legally worth exactly what you payed for it.
As to what qualifies me to give advice on this topic I'm an electrician
with over thirty years in my craft and I have thirty five years of
service as a volunteer fire fighter all of that in fairly busy suburban
companies. I have carried out the dead several times and some of those
were killed by fires of electrical origin.
First if you have nothing to goto the ground screw on the recept you
attach nothing. In this case, he has a few options.
If the box is properly grouned, run a bare copper conductor(solid)
between the ground on the box and recept.
Another option is to removed those little cardboard pieces, and if the
box is metalic and grounded, the yoke 'auto-grounds' to the box, I
don't remember where this is 'allowed' if anyone can refresh my memory
Now here is where you run into problems, if the recept's manufacture
states a ground must be installed, then you only have one option, or
you violate US NEC. Labels and listing.
Remember only qualified personnel should work on electrical systems.
tom @ www.URLBee.com
If you garage isn't a place of assembly or capable of being so(that
would be a good size garage), the US's NEC allows you to use it.
But..... You need to check with local codes, and figure out if the
cable can be exposed to physical damage.
It being a garage he needs to use gfci's in the US.
Good ground would quickly trip the breaker, but being that he's asking
about the cable, he's probly already in violation of the NEC. Only
qualified people to work with electricity. :-P
I have no idea about Canadian laws, but in some (very few) parts of the US,
it is used and Romex type wire is illegal. It's safer too because if
somebody drills or hammers through it, they will hit the shield first.
You need to know how to use it, though. It should be used with metal
junction boxes exclusively. No plastic. It should be cut with a BX cutter,
or a hacksaw (you have to know how, but you cut just one small piece and the
whole thing untwists. It's hard to describe but easy to show.) You also
need to put a plastic bushing at each end.
It's harder to knock the cable out of the connector than it is to knock a
wire off a ground screw, so safety is not the issue if you do it properly.
Incidentally, where I grew up, it was required inside walls, unless you
wanted to use solid conduit. It was not allowed on exposed walls or
I'm assuming that the wire you would normally use is cheap enough that it
should not be a major issue though, unless Canadian wire is vastly different
from what most of the US uses.
You can't depend on metal sheathing to have continuity. The most kosher
way, and would probably meet most codes,
would be to run a green wire (THN, whatever) alongside the bx. The ends of
this wire would be connected just like
the bare wire in 12-2WG. Unless it's a fairly long run, I don't know that
it would be worth the trouble, though.
If the cable has a bonding strip inside the armor it is listed by
electrical testing laboratories as suitable to serve as an Equipment
Grounding Conductor (EGC). You do need to use the connectors that are
listed for use with type AC cable. Those connectors must be made up
tight enough to bond to the metal box. Do not try to use the bonding
strip as a conductor within the box. There are regional preferences for
how to treat the bonding strip at the cut end of the cable armor but
testing done by Underwriters Laboratories showed that the different
techniques had no effect on the impedance of the EGC pathway. You can
cut the bonding strip off flush with the cable end, fold it back over
the end, or wrap it around the end after installing the anti short
bushing so that it holds the bushing in place. Which one you do is a
matter of personal preference.
Since the cable has been tested and found adequate as an EGC there is no
need for Ground Fault Circuit Interrupter (GFCI) protection of the cable
run but GFCI protection may be required for receptacle outlets in a
garage under the locally adopted electric code.
If the receptacles you use are not listed as self grounding by an
electrical testing laboratory then you must bond the green screw of the
receptacle to the box with a short piece of wire by using a machine
screw into a tapped hole in the box. Sheet metal screws may not be used
for that purpose. Alternatively you can use a listed grounding clip
that you force onto the lip of the box after scraping away any non
conductive coatings such as paint or plaster.
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