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Lights stay on

6K views 19 replies 6 participants last post by  Yoyizit 
#1 ·
Hi,

I'm not sure how this can be but my lights stay on even when the light switch is off. I haven't done any new wiring this just started happening about a month ago. When I turn off the breaker for the lights then the lights go off but the switch doesn't seem to matter. I even tried disconnecting the switch in case something was faulty with the switch but the lights stay on.



Any ideas?


Thanks
 
#2 ·
If the AC source is at the light, I'd look there for two wires touching that shouldn't. Else, I'd look at the switch box for the same thing.

If you disconnect the two wires to the switch and measure a non-zero voltage across those wires, please post this info.
 
#5 ·
When the switch for the suspect circuit is in the off position I measure 118 V across the switch. When the switch is in the on position I measure 6.5 V across the switch.

Then I checked a light switch that is working normally and what I see there is that when the switch is in the off position I get 118 V and when it is in the on position I get 0 V.

So now I need to look for the AC source right?
If two wires are touching shouldn't I be getting a blown breaker or something?
 
#6 · (Edited)
Its been my experience, that when a device will not turn off, that its usually a defective switch.
Rarely, do wires become shorted!
Turn off the feed breaker at the electrical panel and remove the switch from the box. Remove one of the wires from the switch and check the switch function with an ohm-meter.
Before reconnecting the switch wire, make sure the switch and wire are clear of a short circuit, turn on the breaker and check to see if the device is turned on.
If not this proves that the switch is defective.
Turn off the breaker again and install a new switch!
You said that you did disconnect the switch in your post.
Your problem could happen if the wires leading to the switch are damaged for some reason. Such as lightening damage or perhaps being chewed by a rodent. This would be unusual and its more likely that the connectors in the light box have fallen off.
At the switch box, if there are 4 conductors in the box [2 white-joined and two blacks connected to the switch] it would point to bad switch.
If there are only two conductors [black and white connected to the switch] this points to either cable damage or some problem in the light box1
 
#10 ·
Lights Stay on

I've uploaded a picture of what I'm dealing with. #1 and #2 are the AC source. When I connect a Voltmeter to #1 and # 2 I get 118 V. Here's where things look funny to me. When I Connect a voltmeter to #2 (yes 2 that is not a typo) and then to ground I get 118 V.

When I connect to #1 and Ground I get no voltage. When I connect to #2 and #4 I get 118 V also when the two wires are touched together then the light that is the problem comes on.

Now this looks to me like someone made the #2 wire the hot wire even though it is white. Does that sound right to anyone else?

Thanks,

William
 

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#15 · (Edited)
I've uploaded a picture of what I'm dealing with. #1 and #2 are the AC source. When I connect a Voltmeter to #1 and # 2 I get 118 V. Here's where things look funny to me. When I Connect a voltmeter to #2 (yes 2 that is not a typo) and then to ground I get 118 V.

When I connect to #1 and Ground I get no voltage. When I connect to #2 and #4 I get 118 V also when the two wires are touched together then the light that is the problem comes on.

Now this looks to me like someone made the #2 wire the hot wire even though it is white. Does that sound right to anyone else?

Thanks,

William
A three-way situation. Changes the name of the game a bit.
Lets get clear on the use of the white conductor. White is usually considered to have a ground or neutral potential, in most cases.
The exception is if its used for 3 way switching.
If a 3 conductor cable with a white, black and red conductor were to be used, the white in some applications could used for power.
In your case it appears that you do not have a red conductor, so perhaps it was wired using 2, two conductor cables instead.
This is not usual, but is legal. Maybe the electrician ran out of 3 conductor cable, so substituted a pair of two conductor cable.
In this case, the power lead would be bridged to all the switches. including the identified terminal of the 3 way switch.
The white neutral lead would be connected to the white of the cable connected to the left switch, the white of the cable connected to the middle switch and to one of the other white wires.
This where it gets tricky. The question is? Which one!
You will have to figure out which of the two cables will be used as switch legs.
This will entail opening up the other 3 way switch location and examining how it was connected. It could be that they used a black from each cable or the black and white of one cable.
Another fly in the ointment, would be if the switch legs were run via fixture box. This would require a somewhat different method.
I would suggest that you would draw all this out on a piece of paper or confusion will reign.
i Googled 3 way switch and found this site [ http://www.thecircuitdetective.com/3and4wyinfo.htm ] perhaps this will help you with your problem.
 
#13 ·
Your white is the constant hot of a switch loop coming from the light fixture where power is feeding the circuit. This is one case where white is allowed to be a hot wire but it should be marked at the termination to the switch with black marker to identify it as hot. The black is the switched hot back to the light fixture. By touching the white to the black you are bypassing the switch and making the light come on.
 
#16 ·
Thank you for the link on 3 way switches. After reading that I know this circuit is not a 3 way switch. Only one switch controls the one set of lights. I'm going to try to follow the AC source wire back to the breaker panel in the basement, I suspect they mis-wired the white as line voltage because the AC source in the wall box doesn't come from a fixture. Also I do have a 3-way switch in the house and when I opened that up I noticed that there they did label the white with some black tape to indicate the hot wire.
 
#17 ·
Well, at least you know that you can control the light from that switch box.
Keep in mind that white neutral will have 118v measured when the neutral feed is disconnected. This voltage comes via a device such as a light bulb.
Electricians are always getting 'poked' form neutral voltages, we assume that its the blacks that are hot, and get careless around the whites.
When I use a volt-meter, I always use the box ground as a reference. Measuring to neutrals can be confusing.
The first thing for you to do is establish the 'true' neutral.
Measure for voltage on all the whites. Then check for a ground on the ones without voltage. (using the ohms scale to the box ground)
Once you know exactly, which cable is the feeder, connect all the whites together.
Then connect the hot feeder to the switches by bridging.
Finally, connect the out-going black wires to the switches.
You mentioned previously that you measured a low voltage across a switch that was in the ON position. This means that there is fault with the switch and it must be replaced.
 
#18 ·
I did manage to find one of the problems. One of the lights outside had been shorted out by someone pulling on the light and the insulation on the wire was stripped off. So Once I fixed the short I reconnected everything the same way it was previously, which was all the whites connected together and all the blacks connected together and then everything works. Thanks for the help. I do have one other issue now but I think I'll open it in a new thread.

Thanks again
 
#20 ·
I did manage to find one of the problems. One of the lights outside had been shorted out by someone pulling on the light and the insulation on the wire was stripped off. So Once I fixed the short I reconnected everything the same way it was previously, which was all the whites connected together and all the blacks connected together and then everything works. Thanks for the help. I do have one other issue now but I think I'll open it in a new thread.

Thanks again
Summary:
Do you believe all the problems were caused by this short?
Is everything fixed now?
 
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