Garbage disposal - switching from hardwired to plug style

[BrianL]

My old badger disposal rusted out inside and leaks, so I got a Waste King unit to replace it. The old disposal was wired directly to the Romex into the wall. The new one has a plug. Is it OK to try to hardware to the new one, or do I need to install a (GCFI) plug? And if the later, can the plug just be bolted to the back cabinet wall or do I need to cut a hole and flush mount it?

 

[frodo]

you can screw the box to the wall
BUT, you have a safety issue here, SO,
STOP HEED this POST
Because under the sink is a WET area, Do NOT screw the box to the back wall undr / around the water pipes or under the kitchen sink valve
screw it to the side of the cabinet or the front.
YES it needs a gfci dedicated circuit. It should already be a dedicated gfci circuit
Check the breaker, and verify it is a GFCI breaker.
I am not an electrician BUT in my state, that receptacle is required to have a on/off switch
A simple light switch is legal install a 4 gang box with a switch on one side and 2 plugs on the other

 

[Jeff Handy]

Post some good pictures of the under sink area.

Are you saying the romex just pokes through the wall, no junction box?

If so, that is totally fudged.

 

[frodo]

that is the way it was done for years

 

[BrianL]

Post some good pictures of the under sink area.

Are you saying the romex just pokes through the wall, no junction box?

If so, that is totally fudged.

BTW, this is my post to:
Replace copper water lines?
Besides those pics there, here's another

 

[BrianL]

you can screw the box to the wall
BUT, you have a safety issue here, SO,
STOP HEED this POST
Because under the sink is a WET area, Do NOT screw the box to the back wall undr / around the water pipes or under the kitchen sink valve
screw it to the side of the cabinet or the front.
YES it needs a gfci dedicated circuit. It should already be a dedicated gfci circuit
Check the breaker, and verify it is a GFCI breaker.
I am not an electrician BUT in my state, that receptacle is required to have a on/off switch
A simple light switch is legal install a 4 gang box with a switch on one side and 2 plugs on the other

If I drill into the wall that the cable is near, I think I'll drill into the dishwasher. Is it not easy to avoid the pipes? Don't they just run from the sink straight down between the joists to the crawlspace?

Also the disposal of course does have a switch up on the wall above the cabinet. You're saying if I added the box under the sink, it would need a switch too (in your state)?

 

[Jeff Handy]

that is the way it was done for years

In my area near Chicago, there is always a junction box, usually on the back wall, out of the way of faucet leaks.
Then an armored cable whip goes from there to the disposer.
Sometimes I change the junction box to a gfci outlet, if the customer’s disposer comes wired with a corded plug.
And if they change from a disposer controlled by the strainer cover to one that needs a switch, it is easy to run a short switch leg to a handy box right near the cabinet door.
On the side without a garbage can under it.
I install a child lock on that door if they have curious toddlers who might operate it.

 

[Alexander Dobert]

National code does not require a GFCI for a disposal, although the manufacturer might recommend and it may be required according to your local code. However, the national code does require GFCI receptacles be easily accessible, which might limit the placement within your cabinet. If you want to have the outlet be GFCI protected (which is a good idea, even if not required), it would be much better to have a GFCI breaker rather than a GFCI receptacle.

 

[Jeff Handy]

I have had some clients who had a gfci breaker for the disposal, and had problems with nuisance tripping.
It stopped when the gfci was moved under the cabinet.
Something about stray currents building up over the longer distance, or something like that.

 

[Mitchell-DIY-Guy]

My new home's disposal was wired solid, with 14-2 NM "Romex" going down through a hole in the bottom of the cabinet. The cable was placed in a piece of Liquid-Tite flexible conduit. Now, I didn't like that one bit. A metal disposal, attached to a metal sink, and no GFCI? In a fixture whose main purpose is moving water? And, the unit isn't double insulated? In my opinion that's exactly and precisely the reason for a GFCI. I never liked the idea of turning on and off a disposal from a wall switch anyway.

So, shortly after moving in, I relocated the wiring to a proper box mounted on the side wall of the cabinet; installed a GFCI outlet there, wired to the cable that formerly went to the disposal. I added a good pigtail for the disposal, and added an air switch...to me, much safer, and far more convenient. Never liked touching a wall switch with wet hands. (thanks, Mom...)

But wait, there's more. The way the entire under sink area was wired was a bit mystifying to me. Like @frodo the receptacle must have a wall switch. For some strange reason, they require the same for a hard-wired dishwasher...now if you have a smart dishwasher with Wifi and some visitor is unfamiliar with all the switches on your wall, they run the risk of accidentally shutting off the dishwasher in the middle of a cycle, or, you'll need to reconnect to wifi or reprogram it. Thankfully on my home (but not my neighbors) these two switches are in a separate duplex box. I put on covers so they do not accidentally get shut off. You can stick your finger in the side if need be to get to the switch.


Then to further complicate things, the electrician ran a 14-3 wire from the main panel to another box underneath the kitchen in the crawl space, sharing the neutral on two breakers. (breakers are joined). In the box, it was separated into two wires, one for the disposal and one for the dishwasher. Not the way I would have done it, but it is what it is.

 

[House Doc]

Paranoia can be a wonderful thing. BUT ... in the 46 years I've been in the business I have never heard of anyone who has been electrocuted by a garbage disposal.
I've install hundreds in the Chicago area, where (at that time) they were all hard wired. And many dozens out here in California where the disposal and dishwasher are both pigtailed and plugged in to 1 non GFI outlet. Only in the last few years have I seen the occasional GFI installed.

 

[Mitchell-DIY-Guy]

Most [disposals that] are hard wired are done so specifically to avoid the cost of a GFCI outlet under the sink. In my case, the shared neutral and wiring in common with the dishwasher was specifically to avoid the cost of running two wires to essentially the same place AND to avoid that GFCI. The outside outlet at my last home was downstream of the GFCI located on the other side of the house, upstairs, specifically to avoid the cost of another GFCI outlet outside. So those are electrical wiring schemes based solely on financial reasoning.

I've never heard of anyone electrocuted by a disposal either. In fact, never knew anyone electrocuted in a house w/o ground wires either...I've had GFCI outlets in my homes for over 30 years; none have ever popped for a real safety-related ground fault, only nuisance issues. Some GFCIs themselves have even failed. Then they get changed. No big deal.

Electrical code is just a minimum standard. Adding GFCI to my under sink outlet for a disposal hardly makes me paranoid.

 

[frodo]

AHHHH.. The GFCI and disposal discussion. VERY goot topic

A disposal is not required to have a gfci
BUT. here is the
"BUTT"
any receptacle/outlet that is within 6' of a sink is required to be a gfci protected outlet
SO, the correct answer to this is if a disposal is hard wired then it is not required to be gfci protected
but if it is a plugged disposal then it is required to be plugged into a protected outlet

 

[Jeff Handy]

Another reason for a plugged disposer to be on a gfci, even a single socket dedicated type, is that at some point something else might temporarily get plugged into there.
A work light, power tool, space heater, phone charger, all things that could fall into the sink or come in contact with water and people.

 

[Rickyman]

I think it was in the electrical code a while ago that stated any appliance coming from the factory without a cord needs to be hardwired. That would include disposals, dishwashers, water heaters, and furnaces

 

[frodo]

My opinion, A disposal should be hard wired, It vibrates , that could make the plug loosen from the wall.

Funny story. YEARS ago, [1979]when I was a appt. I was installing the clips on a kitchen sink,
a sparky [ electrician] flipped on a breaker and the disposal wire ate me up. I came out from under the cabinet with nothing on my mind but giving a sparky the worst ass whipping he ever had. I WAS PISSED!!!!!! I chased the boy from one end of the apartment complex to the other. He was yelling he was sorry and I was yelling . I am fixing to give you something to be sorry about. When I finally caught up to him we both were laughing and became close friends for over 20 years.

 

[BrianL]

you can screw the box to the wall
BUT, you have a safety issue here, SO,
STOP HEED this POST
Because under the sink is a WET area, Do NOT screw the box to the back wall undr / around the water pipes or under the kitchen sink valve
screw it to the side of the cabinet or the front.
YES it needs a gfci dedicated circuit. It should already be a dedicated gfci circuit
Check the breaker, and verify it is a GFCI breaker.
I am not an electrician BUT in my state, that receptacle is required to have a on/off switch
A simple light switch is legal install a 4 gang box with a switch on one side and 2 plugs on the other

Could you answer my response questions to your reply? Thanks!
Garbage disposal - switching from hardwired to plug style

 

[Mitchell-DIY-Guy]

AHHHH.. The GFCI and disposal discussion. VERY goot topic

A disposal is not required to have a gfci
BUT. here is the
"BUTT"
any receptacle/outlet that is within 6' of a sink is required to be a gfci protected outlet
SO, the correct answer to this is if a disposal is hard wired then it is not required to be gfci protected
but if it is a plugged disposal then it is required to be plugged into a protected outlet

As usual the truth is more elusive than that, but nice try @frodo
In some interpretations and or jurisdictions, they have allowed that IF the outlet is separated by a wall or something like it, such as a cabinet, than that normal rule doesn't apply. So since an outlet inside a sink base cabinet is "separated" from the sink by the walls of the cabinet and the counter, then one doesn't absolutely positively NEED a GFCI. In some jurisdictions. And, in some interpretations. That's where someone arguing about interpretations would better be served by just installing the darn GFCI and pose no arguments from the inspector or interpretations. As any professional or amateur knows, there's plenty of possibilities for all kinds of water to be flying around under a sink, so it still makes sense to use a GFCI.

I know Massachusetts adopted NEC 210.8.D before most jurisdictions did, in fact, it's not adopted here in NC. Thus, dishwashers do NOT have to be GFCI protected here in NC but they do in MA. That makes the seemingly and relatively simple act of buying a replacement dishwasher at Lowe's or HD and paying the nominal amount for installation problematic in MA. The installation teams will "plumb" and "wire" a dishwasher, but only a licensed electrician will add a GFCI breaker to the box, and that added hundreds of dollars to the install cost.

In my case here at the new home, the disposal isn't plugged directly into the GFCI outlet; the air switch is. The disposal is plugged into the air switch. Mine is a single outlet air switch: on/off. Many air switches are dual outlet, and only one outlet is energized at a time. These are almost mandatory devices when one installs one of those "instant hot water" faucet things for people who drink hot beverages all day long. That mini hot water heater is kept energized all the time until you use the disposal; then the air switch swaps power to the outlets.

Yes, a disposal can rattle your teeth out and register on the richter scale, but almost none of that will travel along the power cord to the outlet. Today's GFCIs are mostly the TR (tamper resistant) variety and grip the plug like a pit bull anyway, once you can push the plug in!

 

[Mitchell-DIY-Guy]

If I drill into the wall that the cable is near, I think I'll drill into the dishwasher.

You can get a surface mount box. Use screws that penetrate the side wall of the cabinet about ½". Or, get a good solid box w/o the surface mount tabs and drill a couple of mounting holes in it.

Also the disposal of course does have a switch up on the wall above the cabinet. You're saying if I added the box under the sink, it would need a switch too (in your state)?

Yes, the wire from the service panel switches the hot at a wall switch, then the cable continues down to your cabinet. You do not need another switch, that one switch on your wall will energize the outlet (suggest a GFCI but there are those that say unnecessary) and this in turn will power the disposal.

The disposals that I have purchased in the past came with the plug in wire; they ASSUME the unit will plug into an under sink outlet. If you hardwire instead you need to remove the plug in wire (pigtail) and hardware it, ensuring proper fitting to the disposal and proper grounding.

Here is a photo of my undersink. On the back wall is the air switch, and the disposal is attached to that. There is a small ¼" air line that goes to a surface mounted plunger on the counter; that controls the on/off. On the side wall is the box with the GFCI outlet. It's connected to the power through a LiquiTite fitting.

Since with the air switch you do not want anyone monkeying around with wall switch, and in no case do you want anyone monkeying around with the power to the smart dishwasher, those two switches have guards on them.

And yes, there is a high loop on the dishwasher drain, you just cannot see it. The person who designed this kitchen defied convention and put the dishwasher to the left of the sink, not the right. Great for lefties perhaps, not great for most people used to dishwasher to the right.

 

[BrianL]

You can get a surface mount box. Use screws that penetrate the side wall of the cabinet about ½". Or, get a good solid box w/o the surface mount tabs and drill a couple of mounting holes in it.


Yes, the wire from the service panel switches the hot at a wall switch, then the cable continues down to your cabinet. You do not need another switch, that one switch on your wall will energize the outlet (suggest a GFCI but there are those that say unnecessary) and this in turn will power the disposal.

The disposals that I have purchased in the past came with the plug in wire; they ASSUME the unit will plug into an under sink outlet. If you hardwire instead you need to remove the plug in wire (pigtail) and hardware it, ensuring proper fitting to the disposal and proper grounding.

Here is a photo of my undersink. On the back wall is the air switch, and the disposal is attached to that. There is a small ¼" air line that goes to a surface mounted plunger on the counter; that controls the on/off. On the side wall is the box with the GFCI outlet. It's connected to the power through a LiquiTite fitting.

Thanks a lot. Installing a box and switch like that should be easy enough. It'll make swapping out the disposal easier in the future too. How about this one?
https://www.homedepot.com/p/1-Gang-...2-in-Threaded-Outlets-Bronze-5320-2/202056215