testing if light switches were installed correctly

weekendwarrior9 · 09-25-2012, 04:56 AM

I have a suspicion that our light switches were installed incorrectly, what would be the safest way of testing this, short of buying expensive diagnostic tools, or about 100 ft of cable to run back from the main box to use an ohm meter on the neutral on?

I was thinking that I could grab a light fixture and wire up the neutral from a nearby functional plug to it, then connect the wires from the switch (one at a time of course) to the hot line of the fixture.

If the bulb turns on, then the switch is appropriately on the hot line.

If the bulb doesn't turn on, then the switch is incorrectly installed on the neutral.

Or I could shut power off completely to the building, then use an ohm meter between the meter on the outlet to both lines (separably again of course) of the switch.

If the ohm meter doesn't register, then the switch is installed correctly on the hot.

If the ohm meter registers, then the switch is installed incorrectly on the neutral.

This assumes of course that the outlet is installed correctly of course, but so far those seem to be correct.

Just wanted to check my logic (not an electrician obviously, and want confirmation before I call one out to resolve this issue).

**oh'mike** · 09-25-2012, 05:44 AM

A simple $3.00 neon tester is all that you need----open the switch box---pull out the switch and see if there is power going into one side and out of the other--

Do these switches work now?

jbfan · 09-25-2012, 07:56 AM

Why do you think your switches are wired wrong?
When was the wiring changed?

k_buz · 09-25-2012, 08:09 AM

jb has asked the most important question...

Why do you think this? Is it because you opened up a switch and saw a white wire on the switch? If so, you are probably looking at a switch loop, something that was, and still is common and acceptable depending on code cycles.

Ed911 · 09-25-2012, 09:58 AM

Quote:

Originally Posted by k_buz

jb has asked the most important question...

Why do you think this? Is it because you opened up a switch and saw a white wire on the switch? If so, you are probably looking at a switch loop, something that was, and still is common and acceptable depending on code cycles.

That's the way it is in my house...

weekendwarrior9 · 09-25-2012, 12:21 PM

No, because I found another 2 switches on other buildings on our property that this guy did that were on the neutral leg. I found this out because there was a short in one of the light fixtures that proceeded to blow sparks out of every fixture and junction box connected to the subpanel.

After a lot of work I figured out the culprit was a switch that was installed on the neutral leg of a light circuit. I re-wired it to the hot and viola, no explosions of sparks every time it was switched on, even with the short still in the line, 'cause now the breaker would trip properly.

I chalked one switch up to an honest mistake. But then this weekend I found another.

Now I suspect all of the switches the the residential building since the same guy did all the switches last year.

weekendwarrior9 · 09-25-2012, 12:26 PM

And yes, the switches work. But they would if they were on the neutral line anyway.

Pardon my ignorance of electricity, but wouldn't the neon tester be insufficient for testing this situation? Even if the switch were on the neutral it would still register current if I connected the two switch lines since I'd still be completing a circuit by doing so?

Speedy Petey · 09-25-2012, 02:50 PM

Quote:

Originally Posted by weekendwarrior9

No, because I found another 2 switches on other buildings on our property that this guy did that were on the neutral leg. I found this out because there was a short in one of the light fixtures that proceeded to blow sparks out of every fixture and junction box connected to the subpanel.

After a lot of work I figured out the culprit was a switch that was installed on the neutral leg of a light circuit. I re-wired it to the hot and viola, no explosions of sparks every time it was switched on, even with the short still in the line, 'cause now the breaker would trip properly.

I chalked one switch up to an honest mistake. But then this weekend I found another.

Now I suspect all of the switches the the residential building since the same guy did all the switches last year.

Even if the neutral was switched you would NOT "blow sparks out of every fixture".

I have a suspicion that there is no problem at all. Are you sure you were not looking at a switch loop??
HOW do you know specifically that the neutral was being switched?

weekendwarrior9 · 09-26-2012, 03:50 AM

I don't know what to tell you, because it happened.

I installed an additional outside light fixture on a switch. A mounting screw went through the hot, didn't realize it.

The switch was on when i flipped the breaker on for the circuit. Light came on just fine.

When I turned the light switch off, not only did the light stay on but sparks started blowing out of the neutral junctions on completely unrelated circuits. None of the breakers tripped.

I took care of the short first, then started looking into trying to figure out why neutrals junctions on other circuits were getting hot juice during the short. Since the walls were still open, I worked the switch line back to the main panel, and yes the switch was on the neutral.

And additionally, I found that the subpanel wasn't grounded. It had a ground wire and bar, but when i followed the ground line out of the box and into the wall, it ended in the wall. It looked like it was cut a long time ago (cut edge had turned green), and there was no ground connection going back to the main panel.

So, in reference to my original switch referred to in the original post, I went ahead and performed the test I outlined utilizing a light fixture. It was I suspected.

When I opened the receptacle I found the first image. This is suggestive that the switch is on the neutral, but not definitive.

So I hooked the light fixture to the neutral of the outlet, and tried both poles of the switch individual, resulting in pics 2 and 3. No light, no hot, right?

Then I connected the fixture to the suspected hot in the receptacle, and lo, there was light.

**oh'mike** · 09-26-2012, 05:33 AM

Touch the tester to the white and the ground---no light? it's a neutral.

dmxtothemax · 09-26-2012, 05:50 AM

Quote:

Originally Posted by Speedy Petey

Even if the neutral was switched you would NOT "blow sparks out of every fixture".

This is quite true !

Switching the neutral side of a light should not cause this !

Something else is going on !

But it is still considered bad practice to switch the neutral,
Fix this when you can.

I would explain all this to a good experienced electricain
and get him to check everything !

Speedy Petey · 09-26-2012, 06:35 AM

I hope that switch box is not an example of how this place is wired. It is a hacked up MESS. WHERE is the box???
That and the fact that things are shorting out tell me you REALLY should consider getting someone in there to check EVERYTHING out.

rjniles · 09-26-2012, 06:35 AM

Does any one else see what I see? In the first pic there is no electrical box for the switches. They are mounted directly on wood. (also the ground is not connected). If the whole house is wired this way, you have serious issues.

weekendwarrior9 · 09-26-2012, 12:15 PM

1) shorts aren't happening in this building, that was in another one. It's what I found in the other buildings that made me suspect this one.

2) I corrected the ground issue when I was in there, I just shot the photo before I did so to show the lovely example of what I found.

3) Already bought the box, am installing it tonight. Seriously, who does that? Again, wanted the photo for evidence that it was done wrong.

I've been checking the rest of the building out, grounds are connected on the outlets but not on any of the switches. All of the switches that are upstream of their fixtures are wired like this. The switches that are on the terminus of their legs (is that what ya'll are calling a switch loop?) need to be tested but I think I can assume their are on the neutrals as well.

And yes, when I get done evicting this guy I'm having an electrician in to rip all the wiring out and do it up right.

I should post pics of other things I'm finding, call it the "what not to do" nightmare....

sirsparksalot · 09-26-2012, 02:51 PM

Quote:

Originally Posted by weekendwarrior9

1) shorts aren't happening in this building, that was in another one. It's what I found in the other buildings that made me suspect this one.

2) I corrected the ground issue when I was in there, I just shot the photo before I did so to show the lovely example of what I found.

3) Already bought the box, am installing it tonight. Seriously, who does that? Again, wanted the photo for evidence that it was done wrong.

I've been checking the rest of the building out, grounds are connected on the outlets but not on any of the switches. All of the switches that are upstream of their fixtures are wired like this. The switches that are on the terminus of their legs (is that what ya'll are calling a switch loop?) need to be tested but I think I can assume their are on the neutrals as well.

And yes, when I get done evicting this guy I'm having an electrician in to rip all the wiring out and do it up right.

I should post pics of other things I'm finding, call it the "what not to do" nightmare....

We LOVE pics of nightmarish value. Post away.

A switch loop is one where the power source (from the breaker) goes first to a lamp, and then to a switch. In this case, a white wire (but NOT the neutral) will run between the lamp and switch, but it is being used as a black. In this case, of course, there should be a black and white in the switch, with the white wire re-identified as black. I see in your pic, that you have 2 white wires from two different cables to the switch; I don't know what that's all about.