House Renovation Blues (Part 2)

Here’s a weird one. After the fridge thing, I decided to put in a shut-off valve for the fridge line only, so if it ever happened again, to either me (I hope not) or the new owner, I could shut just that off and still have cold faucet and filtered water in the kitchen sink. Shortly thereafter, the garbage disposal (which I’d installed about a decade ago, when we remodeled the kitchen, along with all the appliances) quit working. There is no action when the switch is flipped. I checked the breaker, and it’s not tripped. I can turn it freely with an allen wrench from below, so it’s not jammed, and there’s no hum. However, the armored cable to it from the switch is broken at the interface to the machine, and I can see a black wire-nutted wire sticking out the side, though it seems to be connected, at least from visual inspection.

OK, here’s the weird part. I went to Home Depot to pick up a non-contact voltage detector and a multi-meter to trouble shoot. When I bring the detector near the cable at the interface, I get a voltage signal. But only when the switch is off. When the switch is on, it disappears. When I kill the breaker, I get nothing either way. WTF?

Anyway, I was hoping to avoid pulling (and even worse purchasing a replacement). But it looks like I won’t figure it out without doing so. On the upside, if I do pull the device, it will make it easier to get at the new shutoff valve behind it, which is dripping…

[Tuesday-morning update]

On further inspection, the neutral wire is clearly broken going into the disposal, so off it comes to repair it. I must have done it when I was installing the shut-off valve. That’s why it was sensing voltage on the hot line.

15 thoughts on “House Renovation Blues (Part 2)”

  1. Perhaps the garbage disposal switch has coincidentally chosen just now to go bad? That might explain the voltage weirdness. I’ve had brand-new switches from Home Depot go bad on me within a week of minimal use, and they didn’t necessarily trip the breaker.

    Try unscrewing the switch plate and look/smell for any scorching or burning. If so, replace the switch.

    1. I’m wondering if the switch is on the neutral side of the line, rather than the hot where it belongs. That plus a tripped breaker on the garbage disposal itself would appear to explain symptoms.

  2. Garbage disposals also have a breaker on the motor body. I once replaced a perfectly good disposal not knowing that…

  3. You should also keep in mind that the armor in “armor-cable” is the ground cable! Given its location, and apparent lack of recent use, corrosion may be part of the problem.

    1. Good point. Florida, summer, absence… Do you keep the A/C on to control the inside humidity or use a dehumidifier?

  4. Reminds me of a friend who called a carpenter to repair a couple of clapboards on his house.

    One month later he had a new dining room, flooring* and kitchen….
    True story… 😀


    *According to his carpenter the old floor was being held up by hypnosis….

  5. You know how you can have multiple light switches on a light, and the “on” position isn’t always “on” if you flip the other one? Is it possible that the switch for the garbage disposal is like that, but the situation got reversed somehow? I don’t know how to wire that, so I can’t be more specific.

  6. I don’t think this should be that hard. First, if the outside case of your disposal is metal (skip this step if plastic) take your voltmeter, find a good electrical ground (in Florida I presume not all cold water feeds are copper so you can’t rely on that necessarily) and then set it for 110 and connect the voltmeter between the case and the ground and for both switch positions make sure it reads zero. Then put your hand against the case and flip the switch, if you can feel no sense of vibration then you have no electricity flowing through the motor. You’ll have to disconnect the wiring and inspect, if nothing appears loose, try taking voltage readings at the connections. If those make sense, then it’s time for a new disposal. If they don’t maybe you can just replace either the wire or the switch. You can cut the female end off a short heavy duty (3-wire outdoor type) extension cord, strip and use it to bypass your switch & wiring as a quick check if you are willing to sacrifice one. The people who should read your book will tell you to cut the stripped ends off when done, but they wouldn’t have the guts to do this in the first place.

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