Armored wire question

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Old 09-12-05, 06:33 AM
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Armored wire question

I had run some armored wires from the circuit panel through the walls in my kitchen .. i used armored because the house is all brick with drywall on top of the brick .. so i cut the drywall open, ran the wire, and patched the drywall on top of the wire

Question:

1 - In general, How do u run wires in a brick house with no studs? why are armored wires used and was this the proper use for them?


2- the armored wire has a aluminum ground wire inside of it.. I read in a book that i can just cut that wire an leave it .. i guess because the armored shell is used as the ground .. is that right? DO i still need to use the ground wire in the armored wire and connect it to the ground in the circuit panel?

Thanks.
 
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Old 09-12-05, 06:57 AM
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Someone else will need to answer your first question.

On your second question: that aluminium wire is not the ground wire for this sort of cable. Instead the armor along with that aluminium bonding wire forms the ground conductor. The cable clamp itself is part of the grounding conductor, so you have to pay careful attention to how the clamp is attached. You could simply cut the wire off where you cut the cable, however there is a better technique.

With the AC cable, you will get a package of insulating bushings (red heads), which protect the conductor insulation from the sharp edges of the cut armor. Bring the bonding wire out through the insulating bushing along with the circuit conductors, and then fold it back against the armor, effectively holding the insulating bushing on to the end of the armor. Wrap the bonding wire along the outside of the armor with the spiral for a couple of turns, and then clip it off.

Once the cable is in place in the cable clamp (be sure that you are using clamps that are designed for AC cable), the clamp will hold the red-head in place and will make good electrical contact with the armor. But this little twisting trick holds everything together while you are getting it into the clamp. It also probably give a slightly better electrical connection to the clamp, but I don't think that the latter is a significant difference.

The cable clamp itself provides the grounding connection; because of this you must be very careful about how the clamp gets attached to the box. You must not use 'eccentric' or multi-size knockouts, clamps must be in the solid steel of the box. You must make certain that the locknut is absolutely secure, and you should remove paint around the knockout hole to make sure you have good electrical contact.

-Jon
 
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Old 09-12-05, 10:26 AM
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Originally Posted by switchex
1 - In general, How do u run wires in a brick house with no studs? why are armored wires used and was this the proper use for them?
Sometimes, the original builder of the brick house will install conduit inside the block or brick walls. This makes it very difficult to ever reconfigure or expand the electrical system. Your other options are to build stud walls inside the brick walls, or to use surface mount conduit. Painted metal EMT conduit or a commercial product like Wiremold can be used on masonry surfaces.

Normally, you would not install armored cable on the surface of masonry because surface mount conduit looks cleaner. Ultimately the purpose of conduit or armored cable is to protect the wiring from accidental damage and thereby protect the occupant of the home from fire or electrocution.
 
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Old 09-13-05, 11:24 AM
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thanks for the reply . .i wish i knew the trick of using the aluminium bonding eire to hold the red bushing before! i already have installed and had a hard time keeping the bushing in place .. on a few connection i gave up .. thanks for telling me about the paint around the panel . .i didn't think of that! so the only purpuse of the aluminium bonding is to hold the bushing or does it have any other purpose .. can it be used for ground?

bythe way ibpooks, the house i am talking about was built in 1880! so no conduit in the walls .. that's why i am running armored inside the newly attached drywalls and patching the dry wall
 
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Old 09-13-05, 11:37 AM
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The skinny aluminium will _cannot_ be used as a _alone_ ground wire. It functions, along with the armor itself, as _part_ of the ground conductor. So it _is_ being used as part of the ground conductor inside the cable, and the cable clamp is what attaches it electrically to the metal box. This is why it is important that the cable clamp be properly attached to the box; that clamp _is_ your ground conductor connection.

If you need a ground wire, say to jump to a ground screw on a receptacle, then you attach this ground wire to the metal box. There should be a screw hole at the back of the box for attaching a ground screw.

-Jon
 
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