Missing Junction Box and confusing wiring

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  #1  
Old 08-01-13, 12:40 PM
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Missing Junction Box and confusing wiring

Hi everyone,

I have a 100 year old house which had the wiring replaced from knob and tube by the previous owners. I went to replace an ugly bathroom fixture with a new one and found the following mess behind the fixture. I want to put the new fixture in (and am not sure which size box to get) but the wires coming out of my conduit (especially the red wire that just looks like it was cut) made me want to get advice before I did anything. I ended up putting it all back the way it was but would like to do this myself if I can.

Thanks,
Beth

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  #2  
Old 08-01-13, 12:52 PM
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Not too bad. You have armored cable so you will need to add a metal old work box. Hopefully it is modern A/C cable not BX and has a reliable ground.
 
  #3  
Old 08-01-13, 12:56 PM
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In previous circuits the ground has been reliable.

Do I need to worry about that red wire? And are there any tricks with putting junction boxes in plaster-lathe walls?
 
  #4  
Old 08-01-13, 12:57 PM
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Welcome to the forums!

You are correct, you need a box.

That is what is called AC (Armor Clad) cable. With AC cable you are required to use anti short bushings, which are typically red. Are you sure that the red is a wire and not a bushing? It is possible that somebody used three wire cable and just cut off the extra wire if it is really a wire.
The metal jacket, in conjunction with the small aluminum bonding wire is your grounding path. The cable is not even close to 100 years old which makes me a little worried that there is no grounding path.

Anyway you need to install a metal box like this: Steel City 4 in. Octagon Box with Ears-54151NE-24R at The Home Depot (you will need to turn the ears around)
And some support straps like this: Shop Raco Switch Box Straps/Supports at Lowes.com
Lastly you might want to get a 3/8" AC cable clamp if you want to use the 1/2" KO's

This video might help: Octagon Box: 2-1/8" Deep, 4" Box w/ Four Tabs, Old Work Clips, Side & Bottom Knockouts 54171-DEOW - YouTube
 
  #5  
Old 08-01-13, 01:00 PM
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The wiring is about 8 years old but none of my circuits have had nice green grounding wires - they've all had the aluminum wire. Is there an easy way to check for proper grounding. My concerns are mostly from my hunch that some of the improvements we are dealing with were done on the cheap or "handyman special" are may not be correct.

Thanks for the links. :-)
 
  #6  
Old 08-01-13, 01:42 PM
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Take a meter between the hot (black) and the metal jacket. If you get 120 volts, you ground should be OK. Again, The metal jacket in addition with the bonding strip is the grounding path. The bonding strip alone is not to be used as a ground wire. This is why you need to always use metal boxes and proper fittings with AC cable.
 
  #7  
Old 08-01-13, 02:13 PM
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The metal jacket in addition with the bonding strip is the grounding path.
The best practice is to straighten out the wires, including the bonding wire, and insert the anti-short bushing with the prong on it next to where the bonding wire comes out of the bushing. The bonding wire is then bent out over the lip of the bushing and laid into the grooves on the outside of the cable. About 5 or 6 wraps back up the cable sheath and the rest of the bonding wire can be cut off.

Then the cable with the bushing and the wrapped-on bonding wire can be inserted into the cable connector.
 
  #8  
Old 08-03-13, 06:58 AM
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Is this a wall outlet? If so the best thing would be to use an Old work box with MC clamps install the anti short bushing (Redhead) I would assume that walls have wood lathe so trace the box outline on the wall so as to cut one full lathe and about 1/2 of the top and bottom lathe out and secure the box with a couple of 3/4" number 5 wood screws then install a fixture bar an mount the fixture.use an oscillating tool to cut the lathe if available.
 
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