Moving Electric Dryer, running new cable - need help

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  #1  
Old 03-29-11, 11:42 PM
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Moving Electric Dryer, running new cable - need help

So my old dryer was on the opposite side of the room from the washer and i wanted to move it next to the washer. The dryer is a 4-prong plug in - and was wired with NM cable (3+ground). red/blk to power and white/ground to neutral bar in fuse box. On the outlet end, 3 wires were wired up to plug while ground was wrapped around cable not connected to anything.
After i moved the dryer, i ran new 10/3 BX cable +bonding strap (no ground) and thought i could wire it up the same way (red/blk/white-no problem on the plug ignoring the ground) but on the other end (red/blk/white-no problem) but was wondering if it mattered that there was no ground wire to hook in on the neutral bar. Or maybe should i of picked up another type of cable? 50' 10/3 BX ($44) was half the price of 10/3 nm ($92) so thats why i went with it.

All advice appreciated-Thanks in advance
 
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Old 03-30-11, 04:19 AM
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What you have is actually called AC (Armored Cable), not BX (true BX/Greenfield is very old and is not made anymore). Because it has the bonding strap, you can use it for the dryer. However, the old installation was NOT acceptable. If it was a 4 prong receptacle, the ground wire MUST be connected to the grounding prong. Had the ground wire been properly bonded to the box using a screw or clip, and the receptacle was rated for 'self grounding', it would fly, but not the way you described it.

What you are going to do now is properly bond the Romex to the existing junction box using a green ground screw or ground clip.

Then you will install the AC to that box, using a proper clamp-type AC connector, and backwrapping the bonding strap around the armor (it IS acceptable to do this with AC - it is NOT acceptable to do it with Romex or MC [Metal Clad - has a green insulated ground wire] cable).

Then at the new receptacle, you will do the same thing with the AC (backwrap the ground and use a clamp fitting), then you will bond the ground screw of the receptacle to the box, again using a green screw or a clip.

This ensures a solid connection from the receptacle to the breaker box. As long as it is properly terminated and there are no plastic boxes along the way, the metal jacket (combined with the bonding strap) of AC is designed to be used as a grounding conductor.
 
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Old 03-30-11, 08:06 AM
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Thanks JerseyMatt,

I'd like to get rid of the Romex and just run AC to the box. The Romex is only like 5 feet long so i dont see a point of keeping it. How would I do the connection to the box?
 
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Old 03-30-11, 09:46 AM
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Do you mean the panel box? The same way that you do with a regular junction box. Use the proper size AC box fitting and snug it up in the knockout with a lock ring.
 
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Old 03-30-11, 01:48 PM
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Yes, I meant to the panel/breaker box. But i'm not sure how to connect the AC cable to the breaker box.

Obviously red/blk to the breakers itself and the white to the neutral bar but what should i do with the bonding strip? Should i just backwrap the bonding strap around the armor aand use a clamp fitting at the breaker box?

So the other end, at the 4-prong outlet, i just connect 3 wires (blk/red/white) and backwrap the bonding strap around the armor and use a clamp fitting?

In the end, using this AC, it seems i just have to deal with 3 cables instead of 3+ground?

Thanks again
 
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Old 03-30-11, 02:20 PM
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Originally Posted by krs8808 View Post
Should i just backwrap the bonding strap around the armor aand use a clamp fitting at the breaker box?
Yes. The metal fitting screwed to the metal box is the ground path. Make sure to get the lock nut tight enough so it digs into the enamel.

So the other end, at the 4-prong outlet, i just connect 3 wires (blk/red/white) and backwrap the bonding strap around the armor and use a clamp fitting?
Yes, and you also need to run a 8" piece of green or bare wire from the ground terminal on the receptacle to the ground screw on the metal box to complete the ground path.
 
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Old 03-30-11, 07:48 PM
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Then you will install the AC to that box, using a proper clamp-type AC connector, and backwrapping the bonding strap around the armor (it IS acceptable to do this with AC - it is NOT acceptable to do it with Romex or MC [Metal Clad - has a green insulated ground wire] cable).
I don't care for it, but there is an MC cable with the aluminum bonding strip and no green grounding conductor available from Southwire. The proper connector must be used and not all MC fittings are approved from what I have been told.

MCAP® and HCF MCAP® Cable

http://www.southwire.com/documents/MCAP_BrochureNEW.pdf

http://www.southwire.com/documents/L...ASolidMCAP.pdf

Personally, I prefer MC cable with the green grounding conductor.
 
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