Dishwasher wiring question, anyone have a current copy of the NEC?

In My Humble Opinion
1

TLDR, I’m pretty sure WI (and probably my jurisdiction follows the current NEC, I just want to know the proper way to hook up my dishwasher.
TLDR2, I’d like to avoid a ton of ‘you should probably…’ type guesses, the internet seems overrun with those, even on electrician sites.
Many many years ago I was doing some minor rewiring in my kitchen and as the day wore on we got tired and the dishwasher needed to be connected. It sort of became a ‘screw it, we’ll deal with it later’ and I dropped the wire into the basement, wired a plug on to it and plugged it into a nearby outlet. It’s been that way for over a decade…and it bugs me all the damn time.
I’d like to rewire it properly. My gut tells me to get some 12/2 romex, run a line* from my breaker box to the dishwasher, hardwire it to the dishwasher and connect it to it’s very own 20amp breaker**.
Well, as long as I’m redoing this, I’d like it up to code and I’d rather not have to redo it someday.

I’ve been trying to figure out exactly what I need to do. I’m reading that I need to put plug it into a GFCI outlet, but then I’m reading that you can’t have an outlet under the dishwasher because it would be considered ‘buried’. People are suggesting either putting the outlet under the sink or running the wire to a blank face (just the buttons) GFCI switch above the counter then hard wire it into the dishwasher.
I’m also reading to just use a GFCI breaker, which I’d prefer.

OTOH, I’m reading that GFCIs aren’t to be used for dishwashers as they’ll tend to trip due to false positives (for lack of a better word). That brings me back to my original plan of just running 12g wire from the dishwasher to a 20a breaker and calling it a day.

The next question is, can I leave a few feet of slack under the unit to facilitate repairs without cutting the power and removing the wires? I see lots of suggestions but I know code requires a staple within a few inches of the box.
I’ve been driving myself crazy trying to figure this out. I’ve got about 10 tabs open and just decided that maybe someone here might know more than I do. For the record, I’m in Milwaukee County, Wisconsin.

(PDF)
For those of you still reading, here’s a few relevant cites I found.

IOW, if I’m reading this right, Wisconsin (not necessarily my country of city) follows the NEC). This cite is updated (or says it is) each month.

(PDF, from 2005 and I think things changed in the last few years)
http://dsps.wi.gov/Documents/Industry%20Services/Forms/Elevator/HistoricalCodes/2005%20NEC.pdf

It’s my (possibly wrong, because they don’t define it) that a flexible cord, it just a cord, Romex or extension cord type material, with a plug on the end. Something designed to be removed on at least a semi-regular basis.

Doing even more looking around it appears that the current code actually says that it must be GFCI (and possibly also AFCI protected). I’m guessing my best bet is to just use a 20amp GFCI/AFCI breaker and run 12g wire to the dishwasher, then leave a 18 inches or so of slack just so I can work on it without unplugging it.
If I can avoid having a faceplate above my countertop or installing an outlet under my cabinet I’d much rather do that.

I’m guessing my best bet is to use the AFCI/GFCI breaker and hard wire it. At best it’s in code, at worst I’m not supposed to use that breaker and it’s 2 minutes to swap it out if an inspector has a problem with it someday.

*Honestly, running the new wire, even in an unfinished basement is going to end up being the hardest part and it’s the reason I’ve been putting this off, if it was a 10 foot run, I would have done it the next day. It’s 50 feet, running both directions (across/with joists) and in some pretty tight spots, I have a feeling I’ll just end up drilling holes all the way across instead of trying to run it around the perimeter of the basement.

**I think a 15 amp is required, but for the extra few bucks, why not?

2

Note that local areas can modify the NEC to their liking. And they do so!

Also note that local electrical inspectors usually are happy to answer questions.

With that said, find out where your local electrical inspector’s office is and go ask them if a GFCI is required in your area for a dishwasher. Simple as that!

Also ask about hardwired connections vs an outlet behind the dishwasher or under the sink.

P.S. Get an electrical permit for doing this work. And get your work inspected. This will be good practice for you and you will get the eye and advice of a pro for very little cost.

3

How much is an inspection in your city?
The electrician at work installed a larger load center for me, and it had to be inspected by a local company. As far as I know, they are the only ones allowed to do an inspection. For fifty dollars.

4

Seconding the advise to check with your AHJ (Authority Having Jurisdiction) on the local requirements.

The NEC was updated in 2014 to require GFCIs for dishwashers. If your state/county hasn’t adopted 2014 yet, you can probably get approved without a GFCI.

The relevant bit:
*210.8(D) GFCI Protection for Personnel. Kitchen Dishwasher Branch Circuit.

This new section of the 2014 NEC requires that kitchen dishwasher outlets now have GFCI protection regardless of how the dishwasher is installed. Protection can be provided by a GFCI circuit breaker or receptacle. Electronically controlled dishwashers are prone to end of life failures that increase a user’s risk of shock, so GFCI protection will de-energize the outlet for ground-faults of 6mA or more.*

Some areas throw in a wrinkle of wanting a switch (aka local disconnect) near the sink to cut power to the dishwasher. Some will want it right out in the open so people can bump it with the coffee grinder and kill the dishwasher :smack: and others will allow it to be in the cabinet under the sink, safe from being hit. This is really one of those times being able to ask a local inspector before you do anything is invaluable.

5

Can that be a normal “light switch”? I’ve seen boxes with big read switch levers.

6

I did mine with the 12/2 romex to a dedicated breaker and I made that breaker a gfci type.

If you have one wire in already just use that one to pull the 12/2. Its only about a 1-2 hour job really.

7

You can also access the NEC for free at NFPA.org.

8

Ahh, thanks, I just had to register (for free).

The 2014 version says 210.8(D): Kitchen Dishwasher Branch Circuit: GFCI protection shall be provided for outlets that supply dishwashers installed in dwelling unit locations.

The NEC defines “Outlet” as “A point on the wiring system where at which current is taken to supply utilization equipment”.
I bring that up because I’m seeing people arguing (back from when this came out) that the hardwired connection between the wires and the dishwasher can be considered the outlet and therefore a GFCI breaker is sufficient. I’m also seeing people arguing that based on this, GFCI protection is only required when an outlet (as we would normally use the word) is used…no outlet, no GFCI protection required.

A few things.

Looks like my city has adopted the states electrical code (with a few amendments). Some quick poking around leads me to believe that Wisconsin follows the 2011 NEC which says

Section 210.8(D) Kitchen Dishwasher 
Branch Circuit

Requirements for GFCI protection in dwelling unit kitchens have been expanded. A new subdivision (D), “Kitchen Dishwasher Branch Circuit,” has been added to 210.8. Outlets supplying dishwashers are required to be GFCI-protected, which requires a GFCI-protective device installed at the origin of the branch circuit. The reason is related to different end-of-life failure modes and behavior of newer generation dishwashers as compared to the electromechanical units in the past. [ROP 2-5; ROC 2-29]

So, ISTM that a GFCI breaker would probably be fine. I think the reasoning behind the outlet is to have a nearby ‘shut off’.

I should also mention that my city (not surrounding cities, or even my county or state, just my city) doesn’t allow homeowners to do their own plumbing or electrical work, so, while I could take a chance at an anonymous email, I’m probably better off just keeping the inspector out of it and just wiring this up myself. It’s well with in my ability, I just want to make sure it’s up to code.

One last thing, my dishwasher is about 20 years old, while it may have to be replaced in the next few years (but so far it’s fine), from what I’m reading, GFCI protection is more aimed at new dishwasher because the old ones would trip them by accident.
I think this all comes down to, I have a house built in the 90’s with a dishwasher from the 90’s and I could probably just put a 20A breaker with 12g wire in there and be done with it. If anyone ever noticed (assuming the original dishwasher), it would just look like the builders put it in.

9

here’s what I would do:

  • new 20A GFCI breaker
  • 12-2 w/g type NM cable (romex) to the location
  • normal box with standard 20A duplex receptacle in it
  • normal grounded 3’-4’ appliance cord 9not romex!) hard-wired to dishwasher and plugged into receptacle.

Only change from your original idea is the outlet at the location, and an appliance cord from the dishwasher to the outlet.

10

here’s what I would do:

  • new 20A GFCI breaker
  • 12-2 w/g type NM cable (romex) to the location
  • normal box with standard 20A duplex receptacle in it
  • normal grounded 3’-4’ appliance cord 9not romex!) hard-wired to dishwasher and plugged into receptacle.

Only change from your original idea is the outlet at the location, and an appliance cord from the dishwasher to the outlet.

11

It’s not like an inspector is going to pull out your dishwasher and look at the wiring anyways.

12

Generally it is about $150 for an electrical permit and includes 4 inspections. Prices vary up/down depending on what all you are doing. The larger the building, more amperage, and more gizmos [solar, water well, etc.], the more it costs.

FYI - The above local company doing the inspections is an example of how each area of the country can be different.

As for installing GFCI’s, note if these are GFCI outlets, when they trip, it can be a pain to find the GFCI - to reset it. That is why I feel it is best to install GFCI breakers instead of GFCI outlets. Everybody naturally goes to the breaker panel - so there it is!

13

Excellent. We have a sixty year old house, and while I can replace an outlet with GFCI, I have no idea which is the first outlet on a branch.

14

So, (non) update here. It’s finally time for me to get a new dishwasher. As long as it’s out, it’s time to see what I can do about the wiring (not that it’s THAT big of a deal to do it later).

As I said earlier, I wanted to run a new, dedicated circuit over to the dishwasher. As it turns out that would involve drilling through about 35 floor joists, and that doesn’t include any snaking around ductwork, HVAC equipment, stairs or walls. That…is a lot of work.

My house is a cookie cutter house, there’s at least three others just on my block. The people who originally wired it probably could have done it with their eyes closed. However, they ran all the wires, from the box, (as far as I can tell) to the attic, then dropped them where they were needed. They even did this for the furnace, which is about 15 feet away from the box. I found this out when I went looking to see if there were any other wires running through the joists that I could follow (and use those holes). Even if it got me halfway there it would save a lot of work.
I also checked to see if any of the circuits in that general area happen to be running very light loads, that maybe I could combine them with another circuit and run that one the rest of the way to the dishwasher. Nope, all pretty well loaded up. I’m sure they made sure to use as little wire as possible.
The closest thing I could find is the sump pump. It’s on a dedicated circuit, but even if I wanted to use that one (and I decided against it), it’s ‘landlocked’ by a finished room. I’d have to fish it’s wire over a drywalled cieling and get a new one over to it. Whole big thing.
Similarly, they didn’t do any future proofing. It would have been nice if they had run an extra wire over to that location just in case the homeowner might someday want to install a disposal. They did run me an extra wire for the garage door opener (that the previous owner didn’t notice).

So, as of right now, to be honest, my plan is, once the old dishwasher is out, see what’s going on back there, if I have enough slack to work with, I’m just going to use the one wire to power both the disposal and the dishwasher. It’s amazing how many people, even electricians are saying ‘yeah, it’s not code, but it’s fine, it’s not like you’re running both at the same time and even when you are, the disposal is only on for a few seconds’. If I start blowing the breaker, I’ll deal with it. The two units, together, are more than 15 amps.
And, as others have said (lets just assume nothing goes horribly wrong), it’s not like anyone is checking and I’m not planning to sell my house any time soon. I just really don’t like how it’s set up right now*.

Also, I still see a lot of discussion about where the GFCI can be located and if it’s even necessary. I see people saying it can’t be way down in the corner under the sink because that’s considered obstructed, so they move it up near the door. People installing blank face GFCI ones on the counter to make them ‘readily accessible’. Then there’s all kinds of rules about whether you even need them or not (as well as how much you can load a circuit) depending on if it’s hard wired or not (I’m planning to hard wire this).
Based on all that, my plan is to drop in a 15a GFCI breaker. 2014 code appears to allow for this.
*OTOH, if I’m not going to bring it up to code, maybe I should leave well enough alone. I’m of two minds on this. On the one hand, it’s one thing to say ‘what? It was always like this/I didn’t know you couldn’t do this’. On the other hand, if I do someday want/need to fix it for real, why have someone clean up more mess than necessary, it’s probably easier for them to fix my current situation than for than for me to add wires. Right now, all an electrician would have to do is pull a new circuit. With what I’m proposing, they’d pull a new one, then have to rewire my disposal as well.
I have an electrician friend that’s always happy to do a favor, but what bugs me is that I can’t just say 'hey, just tell me what I need to do" or “what’s code” or “there’s got to be a better way than drilling 35 holes in my floor joists”, and have him give me some guidance. I can ask but it’s always ‘tell me when you’ve got a free afternoon and we’ll just get it taken care of’. Super nice, but I feel bad since he’ll do it (mostly) for free when he could be out on a real job.

15

Can’t you do the same?

There should already be an easy path from the box to the attic, then across the attic and down the wall the dishwasher is on. Should be easy to make a hole in the wall that will be hidden by the dishwasher, and then reach thru there to catch the wire fished from the attic. Then you have a new circuit there. Possible problem is if the stud space behind the dishwasher has headers or cross studs that would interfere with fishing a wire down there. But you can check that out before getting too far into this project.

Also, consider running 3 wires (12-3* NM cable) for this. That doesn’t cost much more than 2-wire cable, but can then be connected to give you 2 separate circuits for your dishwasher & disposal.

*20-amp #12 rather than 15-amp #14 because I believe current code requires all 20 amp circuits in kitchens. And it’s really not much harder or much more expensive to do that.

16

1)I thought of that, I actually meant to get up in the attic and see if all the wires that leave the box and go up through the sill show up in the attic where I assume they do. I’ve been in my attic plenty of times, but never noticed them. However, it’s cramped and full of blown in insulation. Also, the breaker box is on an outside wall so there’s bat insulation there. But, yes, I do plan to look into the possibility of following the wire(s) that they used to bring power to that area. As far as headers, I haven’t checked, I should, but there is at least one wire going down right in that same bay that I would need to use. If there is a header, as long as the hole is big enough to for two wires to get through, it’s just a matter of getting some fishtape or fish sticks through. IME, that’s just a matter of patience. I have, now that I think about it, run speaker wires from the floor to the ceiling without running into any fireblocking/headers, so maybe there aren’t any.
2)If I run a new wire, it will be rated for 20 amps with a 20 amp breaker, no question there.
3)I’ve considered running 12?/3 wire, I’m not worried about the cost, but it is more difficult to work with and you run into the the issue of a shared neutral. If I did that, I’m not sure if it makes more sense to find some way to label both ends of the unused ‘hot’ wire or use both hots and the shared neutral for the dishwasher and disposal and disconnect the other wire. It’s something I’d have to give some thought to.

Or course, it might not even be possible to run these wires through the attic. I meant to look and see if there’s a straight enough shot to just use metal conduit for the bulk of the run in the basement. That would eliminate all the drilling.

17

I’m not sure what you mean by the unused hot.

12/3 contains 3 wires, 2 hots (red & black) and 1 shared neutral (white). Plus, of course, a bare ground wire. You would use 1 hot for the dishwasher, the other one for the disposal outlet, and they would each be on a separate breaker.

18

Will codes let you run wire in the same cable from two different breakers?

19

I was thinking of leaving the disposal alone and running a 12/3 wire, using one conductor for the dishwasher and leaving the other one alone. But if I ever need it, it’s there.
What you’re saying it using this new cable, one hot for the dishwasher, one hot for the disposal and sharing the neutral. Then removing the old wire from the disposal and breaker. Either way leaves me with an extra wire in the walls. Same in the end and, to be honest, I’d rather do it that way so that I know the shared neutral is properly wired.

I haven’t checked my local codes, but I beleive the NEC allows it as long as the two breakers are bonded (SPDT) so that when one flips or is turned off, the other one is off as well. This way you don’t end up with a situation where the neutral is hot. It also makes sure that the two hot wires are on opposite phases so the neutral wire can never end up with twice the amperage it’s rated for.

While poking around in my breaker panel, I did find one shared neutral that wasn’t wired that way. I was kind of surprised. They hots to go two different places, the breakers are in two different places in the box. Maybe it wasn’t code to wire it that way in 97 (looks like it was added in 2008). If I have to add a double breaker to the box for the dishwasher, I’ll probably have to move some breakers around. My thought was to move one of those and so it’s correct in the box.

Long story short, as far as I can tell, my city and state follow the 2011 NEC, shared neutrals, done properly, are allowed in the 2011 NEC and I’ve not found anything in my local or state code that disallows it.

20

Yes it is called a MWBC or Multi-Wire Branch Circuit.

And these ARE VERY DANGEROUS if you do not know what you are doing. There are fairly recent requirements that the breakers be side by side like a 240 volt breaker and that they be tie-bared so both breakers must be turned off at the same time (for safety).