no power at switch


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Old 11-24-15, 12:48 PM
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no power at switch

The garbage disposal quit running all of a sudden. Upon initial inspection, there was some some small electrical-blackened spots noticed adjacent to the slots in the receptacle where the disposal was plugged into. Checking the breaker at the panel, there is a dedicated breaker switch for the disposal, which was not tripped. Anyway I flicked that switch off and back on and tried the disposal again but still didn't run. With a circuit tester I checked for indication of power at the receptacle where the disposal was plugged into, switched on the wall switch for the disposal and got no indication of power with the tester. So with the tester I checked for indication of power at the wall switch for the disposal but got absolutely no indication of power there either. At the breaker switch on the panel there is indication of power. Just at the wires to wall switch there is no indication of power with the tester. The disposal works fine when plugged into a different circuit with an extension cord. At first I was assuming a bad wall switch; I even took the wall switch out and checked the wires for power with my tester but get no indication of power. What could be the problem? What might be the next step to troubleshoot? Any comments/advice appreciated.
 
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Old 11-24-15, 12:52 PM
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Malfunctioning circuit breaker which led to a melted wire perhaps? If that's the case, you'll need to pull a new circuit. And you're lucky it didn't start a fire. If that turns out being the case, I would replace all circuit breakers. How old is your panel/breakers?
 
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Old 11-24-15, 12:53 PM
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Either the internal components of the switch or the receptacle are probably burned out. Replacing both would be a good start. While the boxes are open, checking and remaking any wirenut connections would be a good idea too. Don't use the cheapest receptacle or switch at the hardware get spec grade devices with backwire or sidewire screw terminals, which should be at least $3 each.
 
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Old 11-24-15, 01:04 PM
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Initially, I would say that the wall switch is bad. I would recommend replacing it with a wall switch rated at 20 amps.
You commented at you had no indication of power at the wall switch...........Depending on how the wiring was installed, there is a possibility that you do not have a Neutral conductor at the wall switch. If this is the case, you would only have one cable entering the wall switch box. This would mean that the installing electrician ran the cable from the circuit breaker to the receptacle location first, then installed a second cable from the receptacle box to the wall switch for controlling the garbage disposal. With the circuit breaker turned OFF, you can remove the receptacle and see how it is connected to the other conductors.

Basic wiring 101: If the circuit comes to the switch first, the "white" wires should tap together and the two "black" wires will connect to the switch. If the circuit comes to the receptacle first, the "white" wire will go to the "silver" screw on the receptacle and the "black" wire will tap to one of the wires going to the switch. The two wires going to the switch would connect to the switch, with the "returning" wire connecting to the bronze screw on the receptacle. All grounds tie together and to the grounding points on the switch and receptacle.

If you tester has an ohms setting, you can test the switch with the power OFF at the circuit breaker. Simply place one lead on each of the screws and flip the switch. The meter should read zero ( or very close to zero) if the switch is working properly.
 
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Old 11-24-15, 02:32 PM
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I went with the recommendation to replace the wall switch rated at 20 amps; still the disposal will not run. Actually there are two cables entering the wall switch box. I took a few photos with the new switch connected and the wiring pulled out away from the box and posted them below. Additional comments appreciated, thanks.



 
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Old 11-24-15, 04:52 PM
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Terminology: "At the breaker switch" It is a breaker or circuit breaker not breaker switch.

Tools: "With a circuit tester I checked for indication of power" If you used a non contact tester it is worthless for serious testing. Use an analog multimeter.
What might be the next step to troubleshoot?
With a multimeter, preferably analog, test the voltage at the breaker. Test between the breaker screw and the neutral bar. If you don't have 120v (±10%) at the breaker pull it and look for damage to the bus bar. If the bus bar is good replace the breaker.

If you do have power at the breaker next disconnect the wires at the switch and measure between black and white of each cable. One cable should show about 120v. If neither does retest the cables this time black to ground. If neither cable shows power or power only to ground you might have a bad cable or neutral connection at the panel.

If you do have power at the switch with power on and cable disconnected at the garbage disposal using a multimeter test for 120v at the garbage disposal.
 
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Old 11-24-15, 06:21 PM
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With a multimeter, preferably analog, test the voltage at the breaker. Test between the breaker screw and the neutral bar.
Unfortunately I have a digital, not analog, multimeter. However, if I was to test between the breaker screw and the neutral bar with my multimeter, just to be clear about this, I would touch one of my multimeter probes to the bar my finger is pointing at in the photo below, and touch the other probe on the screw of the breaker with the red wire? Correct? (Breaker shown with red wire is breaker for garbage disposal).

 

Last edited by ray2047; 11-24-15 at 08:46 PM.
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Old 11-24-15, 07:41 PM
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Yes that is correct. But now we have another wrinkle in the problem you didn't mention. The presence of a red wire indicates a multiwire circuit. Is that a 2-pole breaker or a two handle tied breakers? No red wire at the switch so there is probably another box where the multi wire circuit splits before the switch. Your problem could be there. Turn off the other breaker on the multi wire circuit and check in the additional boxes that go dead.
 
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Old 11-24-15, 08:04 PM
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What brand panel is that.... it looks strange.... maybe just the lighting.
 
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Old 11-25-15, 04:44 AM
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What brand panel is that.... it looks strange.... maybe just the lighting.
That is a Siemens panel board with bolt in breakers. He is playing in a commercial space. Also explains the MC cable in the receptacle box.

@ Sgull :

I would touch one of my multimeter probes to the bar my finger is pointing at in the photo below, and touch the other probe on the screw of the breaker with the red wire?
That is correct. You should get 120 volts.
 
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Old 11-25-15, 08:49 AM
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touch the other probe on the screw of the breaker with the red wire?
To be clearer the screw that holds the red wire in. However you also need to find where the red wire goes since I don't see a red wire at the switch. See my previous post.
 
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Old 11-25-15, 01:04 PM
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Upon further inspection, the under-sink receptacle itself (which I neglected to inspect in the initial stage here) it's apparent that a mounting screw for the receptacle box worked its way loose from the wood under the sink, and fell and created contact between the outlet and the metal receptacle box cover. Photo below shows burnt/blackened damaged outlet with remnant of screw.



So now I went ahead and replaced the outlet with a new one but still no luck getting the disposal to run.

I checked the voltage between the breaker screw and the neutral bar and get 120v (+/-10%).

That is a Siemens panel board with bolt in breakers. He is playing in a commercial space.

That is a Siemens panel board with bolt in breakers. He is playing in a commercial space.
Correct ^, Toyln.

No red wire at the switch so there is probably another box where the multi wire circuit splits before the switch. Your problem could be there. Turn off the other breaker on the multi wire circuit and check in the additional boxes that go dead.
So if there is probably another box where the multi wire circuit splits before the switch, I'm not sure how I could locate that other than perhaps investigating other wall switch or wall receptacle boxes nearby for the presence of a red wire. Would that approach make any sense? The red wire from the disposal breaker exits the panel into conduit at the panel box and from there, at this time, I am unaware of where it goes.

You commented at you had no indication of power at the wall switch...........Depending on how the wiring was installed, there is a possibility that you do not have a Neutral conductor at the wall switch. If this is the case, you would only have one cable entering the wall switch box.
It seems indeed there is no neutral conductor at the wall switch; two black wires are connected to the wall switch. There are actually two cables, from what I can tell, entering the wall switch box. Photo below is of the box with the wall switch (terminal ends of two black wires and green wire not seen in photo connected to wall switch):



Tools: "With a circuit tester I checked for indication of power" If you used a non contact tester it is worthless for serious testing.
I have been using a non-contact tester (all I have) to test for any indication of power at the wall switch box but it has yet to indicate any power anywhere within the wiring at the box.

Any further comments/advice appreciated, and thanks.
 
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Old 11-25-15, 01:31 PM
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It seems indeed there is no neutral conductor at the wall switch; two black wires are connected to the wall switch. There are actually two cables, from what I can tell, entering the wall switch box.
Photos indicate thereis a neutral. The two whites connected together are the neutrals.

You wrote:
I'm not sure how I could locate that other
In a previous post I wrote:
Turn off the other breaker on the multi wire circuit and check in the additional boxes that go dead.
Of course it may not be a multi wire circuit but if that is a 2-pole 240 volt breaker or there is two handle tied single pole breaker it likely is.
 
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Old 11-25-15, 04:16 PM
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Photos indicate thereis a neutral. The two whites connected together are the neutrals.
The two whites connected together do not connect directly at all to the wall switch. The wall switch is connected by two black wires (and to green/ground wire).

Of course it may not be a multi wire circuit but if that is a 2-pole 240 volt breaker or there is two handle tied single pole breaker it likely is.
Here's a photo of that breaker:



Further comments/advice will be appreciated. thanks again...
 
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Old 11-25-15, 05:22 PM
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The two whites connected together do not connect directly at all to the wall switch.
Neutrals never connect to a switch. When we say neutrals in a switch box that is what we mean. You have one neutral in and one neutral out.
I have been using a non-contact tester (all I have) to test for any indication of power at the wall switch box but it has yet to indicate any power anywhere within the wiring at the box.
That is a waste of time. You need to use a multimeter to test between the hot and neutral coming in at the bottom and the hot and neutral coming in at the top. The wires should be disconnected when you test. If both sets are dead then you need to start looking for where the red wire goes.

In the breaker box I assume the red wire goes into a conduit. What other wires go into that same conduit? If just a black and white that might help pinpoint where the red wire goes.

If this is commercial the work should be done by a licensed electrician. The fact you didn't know about neutrals in a switch box makes me think you may be in over your head.
 

Last edited by ray2047; 11-25-15 at 05:40 PM.
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Old 11-25-15, 05:52 PM
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It turns out I've been mistaken about the particular breaker for the garbage disposal. Looking a little more closely at the breakers on the panel, I noticed one particular breaker (#11) was just slightly offset from the ON position (the type of breaker that does that when tripped rather with no better obvious indication such as orange color showing). Checking at the key (or map whatever it's correctly referred as) on the inside of the panel door, I discovered that #11 was marked "GD" (for garbage disposal I now know). I switched it off then back to the ON position then tried the garbage disposal and it works now. The #21 breaker with the red wire, although identified on the key/map as "disposal" is obviously not the breaker for the garbage disposal I've been dealing with. Curious, I checked to see the #21 breaker is for the other garbage disposal in a separate kitchen (which is the only other garbage disposal we have), but, strangely, it isn't.

 
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Old 11-25-15, 06:49 PM
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Good you fiigured it out. Well hopefully you will take this as a learning experience. Points learned: You never trust the list of circuits. You always go through and turn all likely breakers off then on that. In this case that would have been all single pole 20 amp breakers then all 15 amp single pole. You never trust a non contacts tester.
 
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Old 11-25-15, 06:57 PM
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hopefully you will take this as a learning experience
Indeed I have. Thanks for all the helpful replies.
 
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Old 11-26-15, 08:29 AM
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You always go through and turn all likely breakers off then on that. In this case that would have been all single pole 20 amp breakers then all 15 amp single pole.
The only exception is when working in a commercial space you can't just willy nilly start turning off breakers or you may have some other workers a bit miffed at you. In that case you first look for tripped breakers, which as you found out is indicated by a breakers in the middle of full on, and full off. You can also use a clamp on meter to see if there is a load on that circuit. If not, then you are fairly safe to turn it off.
 
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Old 11-26-15, 10:02 AM
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When I have a "no power" issue in a commercial account.... yes the first thing to do is to check the circuit breaker that is supposed to be for the device that is dead but I find the panels mis-marked many times. I'll go thru and check every breaker for power out.
 
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Old 11-26-15, 10:27 AM
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but I find the panels mis-marked many times
Agreed! I find they are just for show most of the time.
 
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Old 11-26-15, 10:36 AM
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you first look for tripped breakers, which as you found out is indicated by a breakers in the middle of full on, and full off.
First thing I did in this case was glance at the panel and look for tripped breakers. Didn't notice right away the tripped #11 because, as I described when I did finally notice it was tripped, it trips/moves just slightly from the ON position rather than actually further over to the actual middle where I'm pretty sure if it would've been that kind I would've noticed it upon first glance. Second thing I did was look at the key/map on the panel door, where I saw "DISPOSAL" written for breaker #21. Then I switched breaker #21 to OFF to see if that would cut off the power to the other garbage disposal we have in a separate kitchen, but it didn't.

the first thing to do is to check the circuit breaker that is supposed to be for the device that is dead but I find the panels mis-marked many times.
Yeah in this case I discovered (late and after a lotta hoo-ha) the breaker marked "GD" was the garbage disposal, but that the breaker marked "DISPOSAL" was for neither of our two garbage disposals (and am still rather curious about that).
 
 

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