weird house wiring problem

[Inspector507]

Danny,
Yes that is a back-fed switch or a switch loop ( makes a loop at the switch and comes back). They will work that way even though I would have made the white coming down the hot feed. But yes it will work that way.

 

[Mosey]

Thanks for the help so far! This has been frustrating. I was expecting the hard part to be pulling a new wire through without having to bust up the drywall, so once I got that done I thought I was headed down easy street. Thank goodness for wire fish tapes! The wiring was supposed to be much easier than all this. Anyway, it may be a few days before I get any more done on it, but I’ll let you all know what I find out.

 

[beenthere]

Is running a hot wire to a switch on a white wire according to code? I learned to keep the black hot until after a switch, such as Mosey pictured. I also thought code now says to paint the switched-white black or wrap it with black tape at both ends to indicate it is or can be hot.
(Like Mark in NH's Dad taught him)

 

[MossRoad]

It is a common practice to do it the way it was pictured as long as you mark the white wire with black on each end. The wire is considered hot all the way to the light, where it picks up the neutral. All it is is an extension of the black hot wire before it gets to the light fixture. You will probably find that any house that supplies the feed to ceiling lamps by way of the attic is wired like this.

 

[Inspector507]

beenthere,
There was no code "requirement" to do it that way or any other way. But it was, and still is common practice (at least in my area of the US). The National Electrical Code changed in 1999 to require the installer to idenitfy that white wire as an ungrounded conductor. You can still do it that way as long as you re-indentify it.

 

[PTRich]

I have helped people repair wiring in many old houses before. Some houses used "spider webs" in the attic for hot feeds to the lights and supplied a ground thru a switch for lights, a very dangerouse method. When ever I "fix" wiring in old houses now I replace everything, that way I know it is done right, all the way from the panel to the box. In houses that are very bad I have put in a sub panel for all replaced wiring (I like very neat and orderly panels). You may want to check your oringional wiring, It may be 14-2 because it is just a light. I would use 12-2 for a fan (in fact I use at least 12-2 in everything now).

PTRich

 

[Inspector507]

PTRich,
14-2/with ground is fine as long as you observe the loading and over-current requirements

 

[MossRoad]

That's the way we did it. I put in a sub panel off the old piece of junk and moved all of the major appliances to that with all new wiring. Then I started moving the lighting circuits. When most of the stuff was on the new box, I had a disconnect switch installed under the meter and the feed switched from that to the new box. Then the old box became a sub panel and I am slowly removing the rest of the old lighting circuits from that. We went with 12 also.

 

[Mosey]

I did get a chance to work on this a little bit last night. I got some new switches and did the same ohm-meter tests that I did with the other new switch. I connected one lead of the ohm-meter to the “+ LINE +” (the screw with a black coating on it) side of the switch and the other to one of the switch terminals on the other side (no label and it’s a bright brass colored screw). When I turn the switch on, it goes to 0 ohms, like it should. When I turn the switch off, it goes to infinity, but not right away, it gradually goes up and takes about 12 seconds to get to infinity. All of the new switches behaved the same way. So, I don’t think there is anything wrong with the switch, although there’s still the possibility that I have the wrong type of switch for my application. I called the company that makes the switch, Eagle Electric in NY, 800 441-3177 and talked to a guy named Nick and told him which switch I have, 271W-BOX Combination 2 Single Pole Switches. I told him what it did when I tested it with and ohm-meter and he said the switch was probably bad and to return it. So, he doesn’t really know what’s going on either!

I also did some double checking in the bathroom, with the original switch still in place. With the switch turned off, it reads 125V from the black wire to the metal box (ground) and 0V from the white wire to the metal box. With the switch turned on (light comes on), it reads 125V from the black wire to the metal box and 125V from the white wire to the metal box. With the switch turned off, it reads 125V from the black wire to the neutral side (longest slot) of the plug that’s in the bathroom (which is on a separate circuit) and 0V from the white wire to the neutral side of the plug. With the switch turned on, it reads 125V from the black wire to the neutral side of the plug and 125V from the white wire to the neutral side of the plug. So, it must be wired correctly. If the light was wired backwards, with the switch turned off I would have 125V from the white wire to the neutral side of the plug. Do you agree?

I also got a hold of my brother (who has been out of town in my time of need!). He build and wired his house with the help of his father-in-law who is an electrician. My brother is also stumped.

 

[Inspector507]

Danny,
The present wiring does sound correct. I have no idea why the new switch doesn't work.