November 6, 2005
in the dark
We failed to replace a ceiling light today.
As part of our new effort to spiff up the parts of the house that won’t really get fixed for a while, we attempted to replace a few ceiling lights today. On the last light, one of us didn’t really pay attention to how the wires were connected to the light that we were replacing, and now we can’t figure out how the light ought to be wired.
There are 4 wires behind the light: 1 black, 1 white, and 2 really dark grey. In the photo, #1 is white and #2 is black. The others wires are of an older vintage and are scary and unknown.
I hate electricity.
Use one of those live wire testers that has a little light go on when you have a current. Touch the white and black wires and you should light up. Then touch the black wire and the other two to see if you light up as well as the other two to see if they are still connected. Here are some things you can do if the old wires run to the switch. Use one as a ground wire from the light to the switch. Use the other as a live connection if you want to install a 3-way switch. this will involve running some 12-3 or 14-3 wire to another 3-way switch location. Go buy the Black and Decker Home Wiring book at Home Depot. It explains basic wiring. I used to be afraid of electrical work but it is really quite simple. I put the first of 9 hard wired smoke alarms in today. The hardest part is running the cable.
i noticed when putting up new lights and fans in my house that the ceiling box was often used as a junction box for supplying power to other fixtures. Were the 2 older gray wires wrapped together? If so, you may only need to be concerned about the b/w ones. alternately, the gray ones could just be old and not in use anymore. a voltometer and a basic electrical book will help lots. if you need to use the gray wires - when you say they are old, is it knob and tube old or wires inside of armor cable old?
I’ve been following your blog for a while now, but your electrical troubles moved me to respond.
First, buy the tester that Gary suggested. It will tell you what wires are hot and what are not. Second, buy a book on basic home wiring.
Provided everything was wired properly to begin with, you should be able to figure out how it was all connected. But you need to know what switches are involved, and how many lights. By measuring what wires are hot when the switch(es) are on or off, you can deduce how it should all go back together.
Good luck. I’ve solved some amazingly bizzare wiring problems in my old place (I think my engineering degree helped a little). Give a shout if you get stuck.
I have been stuck in a similar situation before when adding an outlet to an existing circuit. I felt inspired to do it myself and followed a basic wiring book. After my wiring finesse, the outlet stopped working everytime the light turned on. OK, needless to say I called in the electrician. We needed to get some estimates on other bigger work we were planning anyway, so it worked out in the end. I watched him carefully while he solved the problem I created and learned a great deal. After that lesson, if I encounter a 3-way situation, I label the wires coming from the house with masking tape with the color of wire or screw they were connected with prior to removing the wires. Of course, really old fixtures may not have colored wires which complicates things. Watching the electrician helped me to build confidence, but I also now know what I can tackle and what I can’t. For instance, I no longer add outlets to 3-way switch circuits, I let the experts do that. However, since your problem is just a replacing a light fixture, I think you can tackle it. I agree that the tester should help you. You can get a simple one for under $10. It is always good to use these anyway before you start rewiring especially on old houses that you cannot trust the previous work. Good Luck!
ok — y’all have been inspirational. We bought a tester today. Now if we could just buy some time…
“One of Us”? Ouch.
You should really suggest to Lester that he pay more attention when helping you with projects….Its not very nice of him.