Old Wiring, New Switch

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  #1  
Old 12-28-04, 02:03 PM
hermione
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Old Wiring, New Switch

A few weeks ago, I wrote about adding a wall switch to control ceiling lights in the upstairs of my 1926 home. Got some great advice, but now have a new question: some of the wiring in the home has been replaced with Romex, but some of the old fabric-covered wiring remains, as in the ceiling fixture that I want to add the switch to. How can I tell which is the hot and neutral wire? They look alike, and I'm assuming there is no color coding. I figure if I get it right the switch will work, and if I don't, the light will stay on all the time. Am I correct? Thanks.
 
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Old 12-28-04, 02:09 PM
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No you're not correct. The switch will appear to work either way, but if you don't get it "right" it will be unsafe. You need to use a tester of some type to determine which wire is hot. The best I've found is often called a tic, non-contact or proximity tester which makes a sound if the tip is held close to a hot wire. Check at your local hardware store (big orange or blue store...).

Doug M.
 
  #3  
Old 12-28-04, 02:22 PM
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I agree. Get the non-contact voltage "tick" tester, usually less than $15 at Home Depot and fun to use.
 
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Old 12-28-04, 04:47 PM
hermione
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Thanks. The non-contact tester sounds very useful.
 
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Old 12-28-04, 05:07 PM
hermione
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Question

Just to be sure we're thinking of the same tool. I found a Gardner-Bender Non-Contact Voltage Tester at the usual box stores for about $10. Has beeping and light indicating presence of voltage, with range from 90-600 volts. Looks like other similar tools are sold as Christmas light testers, but they seem to do the same thing.

Another item that I think would be useful is a circuit finder. I have one that uses a plug-in on one end, and the other works at the box. However, it would be more useful to have one that works also on a non-contact basis. IS there such a thing? Thanks.
 
  #6  
Old 12-28-04, 10:23 PM
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Sounds like you have the correct tool. That's all you need. Now just hold it near each of the 2 wires at the fixture. The one that makes it light up and beep is the hot wire. A really cool tool. I've had a lot of fun with mine as well. I've even been able to trace wires in the wall with it.

Doug M.
 
  #7  
Old 12-29-04, 06:29 AM
hermione
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Arrow

Thanks for confirmation on the tool. Any problems or special techniques connecting 14-2 romex with the old wiring? it's a 15 amp circuit and the label on the fixture calls for "min 60 degrees circuitry. Also, I was going to carve notches in the joists and lay the romex across, covering with a metal plate, then put the boards back down that serve as the makeshift floor up there. Is that the correct procedure? Thanks!
 
  #8  
Old 12-29-04, 10:41 AM
hermione
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Forgot to mention that the "old" wiring in this house is not knob-tube; it is older sheathed cable, with two wires wrapped in a silver-colored heavy cloth sheath. The newer connections have been made with junction boxes and all seems to be kosher per the home inspection prior to purchase. Thanks!
 
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Old 12-29-04, 11:22 AM
hermione
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Sorry... I was wrong about the type of old wiring. There are several kinds in this house (surprise surprise). The wires leading to this ceiling fixture that I want to add a switch to are similar to knob and tube, with separate hot and neutral wires, all hidden in the insulation in the attic. I was planning on using the ceiling fixture box as a junction box when adding the romex wiring to the switch on the wall. Thanks for any help.
 
  #10  
Old 12-29-04, 11:40 AM
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Too much information... For the sake of this project, just connect a switch loop from the ceiling box to the new switch and put the old light fixture back up exactly as it was, only connected to the switch loop.

Insulation covering knob and tube wire is an issue. Not to make fun of your terminology, but trying to run hot and neutral on the same wire is called a short circuit. Sorry, couldn't resist... If they are separate cables, they're knob and tube. You might start thinking toward upgrading all the wiring to current standards.

Doug M.
 
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Old 12-29-04, 02:13 PM
hermione
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Thanks for keeping me straight on terminology. Actually, almost all of the knob and tube has been replaced, with the exception of ceiling fixtures, probably the hardest to get to. Thanks to all who give advice on this forum for guidance on this and other projects. Have a Happy and Safe New Year!
 
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