Submitted by TonyFugginMontana t3_z7yhm4 in DIY
TonyFugginMontana OP t1_iy8w1a7 wrote
Reply to comment by metarchaeon in Garbage Disposal wired directly into Dishwasher - fixing wiring and adding outlets by TonyFugginMontana
Thanks for responding. Yeah, the plan would be to add plugs to both dishwasher and disposal. As far as the advantage? Beats me, but Home Depot seems to have expected to be able to simply plug in the dishwasher, and the fact they couldn't is one of the reasons I'm installing it myself now, lol. I also just want to be as close to code compliant as possible.
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>As to you wiring, you don't need to run the 12-3 wire to the switch, just wrap the ends of the white wire (that you have capped on both end) with black tape and use it.
I've seen tutorials showing that way, but then I've also seen some say that the new NEC updates for 2018(?) made it a requirement to use 12-3 and include a capped neutral... for whatever reason.
Anyway, if this is the case...
>The box inside the old dishwasher is a valid junction box.
I think that's what I need to hear. If the disposal line can just be spliced in at the junction box inside the dishwasher, the way it was before, without any safety or compliance issues, I would definitely prefer to just do that.
roobinsteen t1_iy90mo2 wrote
Technically neutrals are required in every switchbox now, but if I were in your position I would just do it as described, creating a switch loop. The only reason the requirement for neutrals was codified was so that smart switches would be able to be installed everywhere (smart switches typically require neutrals). It's not for safety, that's the only reason. I don't imagine you or anyone will install a smart switch for you garbage disposal unit.
TonyFugginMontana OP t1_iy947r0 wrote
Thank you. It certainly would be cheaper to reuse the existing 12-2 that is already in place going from the switch instead of buying new 12-3.
rivalarrival t1_iy9vv75 wrote
Neutrals are not required in "every" switchbox now. They are only required for switches controlling lights. Even then, there are seven broad exceptions listed in the code.
Look up NEC 404.2(C).
rivalarrival t1_iy9v7js wrote
>I've seen tutorials showing that way, but then I've also seen some say that the new NEC updates for 2018(?) made it a requirement to use 12-3 and include a capped neutral... for whatever reason.
This is inaccurate. The NEC requirement is 404.2(C), and applies only to switches controlling lights. Even if it did apply to more than lights, you are not obligated to upgrade your switch wiring to the new code.
And even if it applied to non-lighting and you were obligated to update it, there are seven listed exceptions, and three of them would probably apply: #2, you have access to the wiring without removing finishing materials; #4, the switch serves only a specific appliance rather than the entire room; #7, receptacle loads. (If the switch controls a receptacle rather than a light, it does not require a neutral.)
The purpose of the NEC requirement is that "smart switches" need a neutral return to provide power for their circuitry.
The way they had it set up is not ideal from a maintenance and repair perspective (you have to pull the dishwasher to repair the disposal), but is perfectly fine from a wiring perspective.
dominus_aranearum t1_iy95r99 wrote
Current code does require a neutral at all switches.
Nothing wrong with using the j-box at the dishwasher as long as it has enough volume for all of the connectors. Each 12 gauge wire counts as 2.25 in^(3), all grounds count together as the largest, so another 2.25 in^(3) plus whatever gauge the dishwasher wires are (if less than 14 gauge, the conductors aren't counted), plus the cable clamp @ 2.25 in^(3).
12 gauge - 4 * 2.25Ground - 1 * 2.25Clamp - 1 * 2.25 (assuming both 12/2 in one clamp)
Total = 6 * 2.25 = 13.5 in^(3) volume required for the j-box.
I sincerely doubt the j-box on the dishwasher is that large. Changing to 12/3 for the switch would add an additional 2.25 in^(3).
Technically, both dishwasher and the disposer are now required to be GFCI. All outlets/hardwire within 6' of the edge of the sink. This even includes a range hood, fridge, range, etc.
There's no need for two separate outlets. There are two ways to do this. You can use a GFCI outlet or GFCI breaker.
You can use the two outlets you suggested, or use a GFCI/AFCI combination breaker and a single outlet.
First, break the brass bridge on the 'hot' side of the outlet only. Splice the 'hot' (black) and 'neutral' (white) prior to the outlet with one leg going to the top terminals, have the 12/3 head up to the switch. At the switch, cap the neutral, hook up the red to one side of the switch and the black to the other. Back down at the outlet, hook up your red wire to the 'hot' side of the bottom terminal. Double check that you've broken the brass bridge on the 'hot' side of the outlet.
Edit: Forgot that GFCIs don't have a bridge to break. Also, if updating to code, AFCI is required as well.
TonyFugginMontana OP t1_iy99p2w wrote
Thank you, this is great info. Funny you should say that about the dishwasher j-box probably not being big enough. I (stupidly) didn't photograph the original situation but I seem to recall the box was not even closed all the way in the original setup, just partly fastened on one side and bulging open, lol.
With regard to the other solution, (I think) that is one of my earlier plans. I had even diagrammed that way: https://i.imgur.com/d1brqYl.png
But is it actually possible to separate the hot on a GFCI switch like that? It seemed like the GFCI switches like this one don't have the brass tab to break the connection. They just seem to have a designated "line" upper half and "load" lower half.
dominus_aranearum t1_iy9c5g3 wrote
Brain fart. GFCI outlets don't have a bridge to break off so personally, I'd switch to a GFCI breaker and use a single outlet that has the bridge.
Technically, code requires them to be AFCI as well now, so I'd get a GFCI/AFCI combination breaker.
TonyFugginMontana OP t1_iy9dfgo wrote
Thanks. I'm a total newb to all this and it's taken me days to get to this point, so I have no idea what replacing the breaker would entail. But I'll look into the possibility of doing that since using a standard outlet with half-hot switch wiring would be easier and cheaper.
dominus_aranearum t1_iy9eq6e wrote
Going the breaker route probably won't be cheaper. Depends upon your electrical panel. GFCI/AFCI breakers can easily be $70.
If I were you, I'd just get the GFCI breaker and not worry about the AFCI. There's some debate as to whether they should be used or not.
mr78rpm t1_iy9fnq4 wrote
Picky detail here: First, all of the parts for this wiring should be rated for 15 amps.
EDIT: I missed the fact that you're describing everything in terms of 12 gauge wire, which is to say, the wire gauge and all other details that are appropriate for 20 amp circuits. My experience has only been with 15 amp GFCIs, so that's what I wrote about. It doesn't matter which amperage rating you wire for, as long as it's done properly. One example of this "properly" is that if the feed Romex were 14 gauge, you would not be allowed to wire up the rest of it using 12 gauge. The way to think about this is: As you go further away from the panel, you either use the same wire gauge or smaller wire gauge (see my note somewhere else here... smaller gauge means larger wire gauge number).
Second, your final drawing shows the correct wiring but... look up a 20 amp outlet. Your drawing intends to show outlets rated 20 amps, where the hot plug holes are vertically oriented and the neutral plug holes are horizontally oriented. But it shows 15 amp sockets, where the hot and the neutral holes are both vertically oriented. This is minor in this discussion, but if someone decides to get this exact hardware and wire it up EXACTLY as shown, there can be difficulties. (Plus, this particular set of wiring parts should be 15 amp rated, not 20 amp.)
Don't be confused when you read "(if less than 14 gauge,...)."
I know how this should be wired but I don't know how to interpret the part in parentheses above. See, a wire that is smaller in diameter, which could be described as "less," has a HIGHER size number; a wire that is larger in diameter has a LOWER size number. For instance, 14 gauge wire is thicker than 16 gauge wire.
dominus_aranearum t1_iy9kldp wrote
You say that all the parts here should be rated for 15A, but then go on to say the drawing intends to show outlets with 20A sockets. First, not my drawings. Second, why? 15A receptacles are rated for a 20A pass through and OP's drawing doesn't even have a pass through to another potential 20A outlet. By limiting the sockets to 15A, no 20A appliance can be run through a 15A switch, which would be the only potential concern here.
Why do you feel that the wiring should be rated at 15A vs. 20A? There's nothing wrong with wiring using 12 gauge for a 15A or 20A circuit. OP has a 20A circuit, which is wise when both a dishwasher and disposer share a circuit.
Anyone who wants to be confused by (if less than 14 gauge) shouldn't be doing their own wiring. Why would I list the volume requirements for 12 gauge, then go on to say less than 14 gauge isn't counted? People were confused by 1/4lb burgers vs. 1/3lb burgers as well, thinking that 1/4lb was bigger. These aren't the people who should be doing electrical work or ordering my food, even as a DIY.
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