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-   -   no power going to the light switch (http://www.diychatroom.com/f18/no-power-going-light-switch-25604/)

baseballfan 08-22-2008 06:28 PM

no power going to the light switch
 
hi guys, i am new here. ok my problem is that there seems to be no power going to the light switch. i changed the switch and still no power. the light just stop working one day, just like the light in the bathroom and the problem was the switch which i replaced. then the other light stop working so i thought it might be the switch which i changed and still nothing. now i used one of those power detector things whatever they are call lol, and the light won't light, do u thing it is a wiring problem then.:(

SD515 08-22-2008 06:53 PM

Could be a few things...a bad old and new switch...not likely but possible. More probable is a broken wire or wire joint, blown fuse/tripped breaker or even a tripped GFCI (which could be a breaker or a receptacle, and not necessarily in the same room). The best way to check to see if there is power entering the switch box is with a voltmeter. If you don't have power in the sw box, then the problem lies somewhere in the circuit between the sw box and the breaker/fuse box. Do you know what else is on the circuit, and have you check those?? Check all the fuses/breakers??

Super33 08-22-2008 11:13 PM

Also you might want to check any GFCI outlets in the area and reset them. It's not likely but it is possible. Is that switch the only thing not being fed? Use your tester and check the surrounding outlets. Maybe it's a loose splice in the switch box that was shaken loose when you replaced the bad switch. Perhaps it's a loose splice in the bathroom switch when you replaced that one?

baseballfan 08-22-2008 11:34 PM

thanks for the response, there is no braker it is a fuse i checked it by switching it, i also put a new one. no gfci outlet in the bathroom or around old house maybe. one weird thing i didn't see a ground wire in the box where the switch is. i also check all the outlet around and switches everything has power going to it, i used my meter. so maybe it could be a broken wire. but what could have had happened since it was working fine and one day it just stop working.
like i said before same problem in the bathroom but it was just the switch cause after i changed the switch the lights work again.

SD515 08-22-2008 11:50 PM

If it's an old house, there may not be a ground wire in the sw box. Years ago they only used 2 wire cable without ground for these kind of things. So far it sounds like a broken wire or bad connection somewhere. What caused it?? Won't know 'til the problem is found. You say you have a meter...that's good. Did you use it to verify there is no power coming into the sw box?? You can use an extention cord if you don't have a receptacle close to the sw box. Just be careful...remember this is live electricity.

baseballfan 08-23-2008 12:05 AM

yeah i used my meter to check if power is coming tru, but no there is no power, there is a receptacle in front of the wall where the switch is, and behind that wall whci is the bedroom, the problem switch is in the hall way. well so far it looks like it is a broken wire or maybe a bad connection. is it usual for a wire to get broken or disconnected somehow. and would this be a easy job.

SD515 08-23-2008 11:57 AM

Quote:

Originally Posted by baseballfan (Post 150986)
... well so far it looks like it is a broken wire or maybe a bad connection. is it usual for a wire to get broken or disconnected somehow. and would this be a easy job.

It shouldn't be too hard of a job...it's a matter for finding the break in the system. Many times when you remove a receptacle, for example, you can see the burnt wires. Sometimes the break is inside the cable inside the wall and can't be seen. Then you would do a continuity test on the cable. Power off of course.
I find a lot of times in old houses the culprit being a broken/burnt wire, but a loose connection is still very possible. Often I find a burnt wire, usually the white neutral, due to 'over-fusing'...someone puts a larger fuse in than the circuit is designed for. I find a lot of 20 & 30 amp fuses put in when the circuit is designed for 15.
If there isn't power entering the sw box, the next step is to locate where the incoming feed to the sw box comes from. If there is only one cable entering the sw box, then that cable should be coming from the light fixture box. If there is 2 or more, it might be coming from a receptacle box...maybe below it on the same wall, but not necessarily on the same side. Kill the power first, see what other outlets/lights, etc. 'died'. If you don't know where the switch feed cable comes from, start with the closest device (that is 'dead') to the sw box.
Is this a single pole switch?? (sounds like, light controlled by one switch) or a 3 way?? (2 switches control the light)

baseballfan 08-23-2008 01:21 PM

yeah it is a single pole switch, it seems like only one cable entering the box, i can only see a black and white nothing else without having to take the box out. so i guess it is the white coming from the light fixture box tothe switch. or maybe i hope i am lucky it is just loose on the light fixture box. i will have to check that out.

Wildie 08-23-2008 03:09 PM

If you only have one cable to the switch box, this means that there will be no neutral in the box.
You say that the box is not grounded, so you will not have reference ground for your meter.
When testing electrical circuits, you must always be sure of a proper reference ground. Be it a tap in the bath room or a long piece of wire run from a water pipe etc.
If you measured for voltage on the switch terminals, what did you use for the reference ground?

baseballfan 08-23-2008 10:19 PM

ok man u confusing me now, lol with the reference ground. i gues what i mean is that there is a black and white cable going in i think i said this on another thread sory if i didn't, but not ground cable.

SD515 08-23-2008 10:55 PM

Getting a 'reference ground' when using a meter basically means that one of the meter leads is touched to the neutral/ground bar of the service panel. Since the meter isn't going to have a 100 foot long test lead so we can hook it directly to the bar in the panel, we use a known ground or neutral close to the device wiring we want to check. The ground hole and/or neutral (wide) slot of a nearby receptacle in many cases. Sometimes an extention cord is easier...it's the same thing as a receptacle. So, to test for presence of electricity, we put one lead in the ground hole or neutral (wide) slot and touch the other to the wire end.
In your case of having only one cable, 1 blk & 1 wht, you'll have to test both of them to ground. (Nowadays code makes us use the white wire, taped black at both ends of it, to feed the switch and return from the switch on the black. Your house being older may or may not have been done that way.)
If one shows voltage, the other shouldn't, and a good circuit should show around 120 volts. What it sounds like you have is called a switch leg. Power comes down one wire, goes through the switch, then up the other wire to the device being controlled. As Wildie mentioned you won't (or shouldn't) have a neutral in the sw box. I know this is wordy, but does this make sense??

Wildie 08-24-2008 04:30 PM

Quote:

Originally Posted by SD515 (Post 151203)
Getting a 'reference ground' when using a meter basically means that one of the meter leads is touched to the neutral/ground bar of the service panel. Since the meter isn't going to have a 100 foot long test lead so we can hook it directly to the bar in the panel, we use a known ground or neutral close to the device wiring we want to check. The ground hole and/or neutral (wide) slot of a nearby receptacle in many cases. Sometimes an extention cord is easier...it's the same thing as a receptacle. So, to test for presence of electricity, we put one lead in the ground hole or neutral (wide) slot and touch the other to the wire end.
In your case of having only one cable, 1 blk & 1 wht, you'll have to test both of them to ground. (Nowadays code makes us use the white wire, taped black at both ends of it, to feed the switch and return from the switch on the black. Your house being older may or may not have been done that way.)
If one shows voltage, the other shouldn't, and a good circuit should show around 120 volts. What it sounds like you have is called a switch leg. Power comes down one wire, goes through the switch, then up the other wire to the device being controlled. As Wildie mentioned you won't (or shouldn't) have a neutral in the sw box. I know this is wordy, but does this make sense??

Well said! SD515

SD515 08-24-2008 08:36 PM

Quote:

Originally Posted by Wildie (Post 151335)
Well said! SD515

Thanks :biggrin:

220/221 08-24-2008 11:17 PM

Both the black and white come from the ceiling light j box. White is hot (coming into the switch) black is the switch leg going back to the fixture.

Wire nut them together to eliminate the possibility of a bad switch.

Next step is to take the fixture down. Inspect the socket, the leads and check connections in the jbox.

If all the oulets in the room are working, the problem will be in the fixture wiring or JB.



But FIRST......Make sure the fixture has a bulb that you KNOW works. Screw it into a lamp and test it.:jester:

wilsonmian 08-26-2008 01:08 AM

It looks like purely a switch problem to me. One of my room's switch behave in the same way with water in their screws.


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