Garbage disposal plugs in under the sink. If the breaker box is to be believed it is on its own circuit. A while back the switch will not turn on the disposal. I get under the sink and plug it into the other outlet and it turns on even with the switch turned off. So all of the sudden, one outlet is always hot, the other outlet is never hot and the switch makes no difference. I also noticed that the outlet under the sink was not a GFCI outlet (pretty sure code doesn’t require it) but as long as I’m going to replace it to fix the bizarre symptoms I 'might as well replace it with a GCFI.
OK, here we go with you diagnosing the issue and confirming (or denying) my plan. There are two hot wires running into the existing outlet with one neutral and one ground wire. I plan to cut the wires, pigtail the two hot wires to the line side, the solo neutral to the line side as well and there would be no wires coming off the load side. Does that make sense and what could be possibly wrong with the outlet that despite being on a switch the hot side stays hot and the cold side stays cold (like a McDLT)
ETA: the disposal is only on one pole according to the circuit breaker. Turning off the breaker appears to have killed both hot wires. My multimeter has those stupid stubby leads that I hate and makes it hard to make contact with the bare metal.
My first thought was to replace the outlet incase there was a break causing a short in the other outlet.
I have heard that the two hots may be because the one outlet is always hot (I cannot confirm I ever used it before this with or without the switch) and the other is switched but both on the same circuit. I’m beginning to think that’s what’s going on but then how would I wire it to a GFCI?
On a typical socket, there’s a tab to break off if you want the top and bottom to be separated. This is typically to allow one socket to be “always on” and one to be switched.
So your two ‘hot’ wires are probably ‘always hot’ and ‘switched’.
You don’t want to join those together, or you lose the function of the switch. It sounds like your socket was probably fine, and it was the switch that was bad.
You would wire these to a GFCI the same as you would a regular socket. There might be a wiring diagram in the package when you purchase it. You want to break off the tab so the switch can work.
I suggest getting one of these to test it is wired correctly.
I was thinking the switch is broken as well. Especially if nothing changed, but the disposal stopped working one day.
OP, you’ll need a voltage tester to do this job safely. Not only to make sure the power is killed, but you can also use it to test the switch.
It’s why your current outlet is acting the way it is. The always hot side was always, always hot. The switched side sounds like it’s now being fed by a bad switch.
If you have a multimeter you can verify this pretty easily. Pull the outlet out, identify which side is hot (measure from one screw to ground), move to the other screw and see if flipping the switch turns the voltage on and off…I’m guessing you won’t anything on the switched side.
Right now half your duplex outlet is wired to be hot all the time, the other half controlled by the switch. As @tofor mentioned, one of the two “hot” wires you see is switched, the other continuously hot. If you pigtail them together that will bypass the switch and the outlet will always be hot.
To replace the outlet with a GFCI on a switch (waste of money IMHO), connect the switched hot from the old outlet to the line side of the GFCI and cap off the unswitched hot.
Of course as everyone else is saying the problem is probably a bad switch rather than a bad outlet, so your switched GFCI outlet still won’t work…
That has a high probability of going wrong.
IF, the two hot wires going into the outlet box are fed by two separate breakers and those two breakers are out of phase, the voltage across those two wires will be 240 and you’ll have a dead short as soon as you turn the power on (because one wire will be at +120 and the other at -120).
If the two hot wires and single neutral wire are the actual feed coming up from your breaker box, that’s a multiwire branch (or ‘shared neutral’). They should be on different phases, that’s what allows you to use a single neutral wire. They really should also be on a double breaker so that if one trips or is manually turned off, the other one is as well, but that’s a semi-recent addition to the code.
If the two wires are on the same phase, it would be against code and there are risks, but it’ll likely be fine. What would happen is it’ll take more amps to trip the circuit and the neutral wire could get overloaded. To be clear, by ‘it’ll likely be fine’, I’m not saying you should do it, I’m only saying that it’s not likely to set your house on fire the first time you turn on the disposal. You’ll run into problems if you start pulling more than 15amps since the breaker won’t flip and that’s likely what the neutral is rated for.
If you only want a single hot wire, you’re better off abandoning the unused one instead of looking for something to connect it to. Cap it off in the box and if that wire is the only thing on that circuit, either turn that breaker off or even take the wire out of the breaker and cap it off in the breaker box as well. Just remember that it’s there. If you ever want another outlet under the sink, it’ll be right there waiting for you.
I think he doesn’t really have two hot wires, just two black wires - one actually hot from the breaker and a switched hot from the switch. Hard to tell for sure without knowing what else is in the box.
I assume that’s what’s going on as well, or something along those lines.
Sometimes I think it would be nice if community colleges would offer some type of beginner’s electrical class that, upon completion, would give you the [legal] ability to do certain types of electrical work in your own house in jurisdictions that require you to call in a licensed electrician. And, when I say ‘certain type of electrical work’, I’m talking about small things like replacing an outlet or maybe adding light to a room. Nothing to big or complicated.
But then I think that you’ll wind up with people comfortable enough to [think they can] do the job but find themselves in situations like the OPs and not realize they might be in over their head.
I’ve always done all my own electrical work. A few times I thought about getting licensed since even though my work is all up to code, it’s technically not legal. No permits, no electrician etc. But, at least in my state, it takes several years of trade school and thousands upon thousands of hours of apprenticeship to be able to work on your own, plus continuing education to renew the license. It’s really not something worth getting unless you plan to make a career out of it. OTOH, I picked up my HVAC license online.