Setup for Dishwasher & Disposal

[busman]

I've got a kitchen renovation that has an existing multiwire circuit for the dishwasher and disposal. Was planning on a duplex receptacle, but the disposal isn't listed for cord and plug. My plan was the following:

Place a 1900 box under the sink and add an extension ring that will extend into the cabinet. Run a cable from the extension ring to the disposal and put a receptacle on the RS cover for the dishwasher. Any better ideas? Photos.

I guess I could do all this with a plastic box in the wall, but for some reason, I'm not crazy about romex cables poking out thru the wall finish and cabinet back. There's also the problem of cabinet installers not cutting a big enough access hole that you can get to the flush mounted box and remove the cover. The extension ring would insure a big enough hole and provide good access for future changes. Thoughts?

As always, thank you.

Mark

 

[augie47]

No problem, although a couple of thoughts came to mind.
Is the garbage disposal switch controlled ?
(If not a switch might be needed be 422.32)
Secondly, and one of the most ignored "rules". UL Standard 749 states in part:

UL Standard UL-749
UL 749
Household Dishwashers
7.3 Installation instructions
7.3.1A Where the installation instructions for a built-in dishwasher specifies
that the appliance is able to be connected by means of a power-supply cord
not already attached to the appliance by the manufacturer, the instructions
shall specify that a power-supply cord kit marked for use with dishwashers
shall be used. The cord kit shall comply wi th Clause 25.2A. The part or model
number of the power-supply cord kit shall be included in the appliance
installation instructions.

so, if you want your install to be squeaky clean (pun intended), you need a factory cord on the dishwasher.

 

[busman]

No problem, although a couple of thoughts came to mind.
Is the garbage disposal switch controlled ?
(If not a switch might be needed be 422.32)
Secondly, and one of the most ignored "rules". UL Standard 749 states in part:

UL Standard UL-749
UL 749
Household Dishwashers
7.3 Installation instructions
7.3.1A Where the installation instructions for a built-in dishwasher specifies
that the appliance is able to be connected by means of a power-supply cord
not already attached to the appliance by the manufacturer, the instructions
shall specify that a power-supply cord kit marked for use with dishwashers
shall be used. The cord kit shall comply wi th Clause 25.2A. The part or model
number of the power-supply cord kit shall be included in the appliance
installation instructions.

so, if you want your install to be squeaky clean (pun intended), you need a factory cord on the dishwasher.

Augie,

Thanks. Yes, the disposal is on a switch above the sink. Didn't know that about the dishwasher, although when I read the instructions for this model, it did specify that cord was OK, but I don't remember seeing any mention of a cord kit. I'll check again and let you know.

Thanks again,

Mark

 

[augie47]

I don't recall anyone ever using one, but the "rule" is there....

 

[Dennis Alwon]

I don't recall anyone ever using one, but the "rule" is there....

That is one of those rules that never gets inspected. Not sure why it is there. Personally I never install a plug for a dishwasher unless it is installed by the manufacturer. Some models come with cord and plug.

Here is what I do--if anyone cares. :grin: I install a box under the sink with a tail out to the dishwasher. If the dw comes with a cord and plug I simply install a receptacle under the sink and disconnect the tail to the dw. If not, then I install a switch and direct wire the dw.

 

[busman]

That is one of those rules that never gets inspected. Not sure why it is there. Personally I never install a plug for a dishwasher unless it is installed by the manufacturer. Some models come with cord and plug.

Here is what I do--if anyone cares. :grin: I install a box under the sink with a tail out to the dishwasher. If the dw comes with a cord and plug I simply install a receptacle under the sink and disconnect the tail to the dw. If not, then I install a switch and direct wire the dw.

Dennis,

Do you install a flush box? If so, how do you remove the tail after the rock and cabinets are up? That was where I was going with the question. It seems the only way to have that kind of flexibility is to have a surface box or a flush box with extension ring. Maybe I'm not picturing it right.

Thanks for the feedback.

Mark

 

[goldstar]

Aside from the UL spec that Augie mentioned as far as I can recall I've only had one installation in the last 10 years where a DW came with its own cord and plug. But, since that point I've always purchased 6' of SO cord and a plug and installed a receptacle in a 1900 box inside the sink cabinet. That way I can wire the DW when it arrives on the job and leave the rest for the plumber to install. The way I see it, it's a neater and safer installation than having a piece of RX cable sticking out of the flooring and connected directly to the DW and it satisifies the need for a disconnect means. Otherwise, you'll have to install a breaker lock-out device on the DW/disposal breakers. IMHO having a local disconnect means makes it a lot easier for anyone servicing the DW, and the plumber or HO won't have to go to the breaker panel and figure out how to use the lock-out device. They can barely figure out how to reset a breaker.

You can use the same cord and plug set-up for the disposal. However, in your case it appears the HO is not getting a batch-feed type disposal so you'll need to switch 1/2 of the duplex receptacle.

BTW, I once tried using an adjustable 1-gang box inside the sheetrock but the carpenter had a difficult time cutting the hole exactly right in the backing of the cabinet.

 

[iwire]

No problem, although a couple of thoughts came to mind.
Is the garbage disposal switch controlled ?
(If not a switch might be needed be 422.32)
Secondly, and one of the most ignored "rules". UL Standard 749 states in part:

UL Standard UL-749
UL 749
Household Dishwashers
7.3 Installation instructions
7.3.1A Where the installation instructions for a built-in dishwasher specifies
that the appliance is able to be connected by means of a power-supply cord
not already attached to the appliance by the manufacturer, the instructions
shall specify that a power-supply cord kit marked for use with dishwashers
shall be used. The cord kit shall comply wi th Clause 25.2A. The part or model
number of the power-supply cord kit shall be included in the appliance
installation instructions.

so, if you want your install to be squeaky clean (pun intended), you need a factory cord on the dishwasher.

Augie I agree but want to mention that you did not highlight an even more foolish part of the UL requirements.

We can't use just any dishwasher cord, it must be the 'right' dishwasher cord. :roll:

The part or model number of the power-supply cord kit shall be included in the appliance installation instructions.

 

[iwire]

In the 80s I was doing tons of condos and we would just leave a 4' whip of NM stubbed out of the wall and tie that right into the DW.

 

[Dennis Alwon]

Dennis,

Do you install a flush box? If so, how do you remove the tail after the rock and cabinets are up? That was where I was going with the question. It seems the only way to have that kind of flexibility is to have a surface box or a flush box with extension ring. Maybe I'm not picturing it right.

Thanks for the feedback.

Mark

Mark you are over thinking this. All you need to do is disconnect the wire in the box that goes to the dw.:grin:

Yes, I install a flush box but you certainly can install a surface box also.


If a cabinet installer can't get the cutout correct for a flush box then he has no business being an installer.

 

[Little Bill]

Mark you are over thinking this. All you need to do is disconnect the wire in the box that goes to the dw.:grin:

Yes, I install a flush box but you certainly can install a surface box also.


If a cabinet installer can't get the cutout correct for a flush box then he has no business being an installer.

Dennis,
You answered this question a month or so ago about "hard wiring a DW." I was wondering why you coudn't put a box in the side of the cabinet, between the DW space and under the sink? In other words, side of cabinet under the sink next to DW space. I guess you would have to protect the wires in some way, but NM cable to a DW usually isn't protected in the ones I've seen.
Any thoughts on this set up?

 

[kwired]

If a cabinet installer can't get the cutout correct for a flush box then he has no business being an installer.

None of them around here are installers then.

The trick is to not try to cut the entire opening out before putting the cabinet in place. Measure and mark the center of cut out and make a hole there smaller than the required finished hole. Install the cabinet, and then come back with rotary cutout tool and finish the cut out in place, perfect every time. I have even told them I will finish the cutout myself if they will just put a hole in the center so I know where to start when I get there.

 

[Dennis Alwon]

If they screw up they can always install a new piece of luan (thin veeneer) to the back with the hole in the right place. If a sheetrocker can do it then a cabinet guy should be able to.

 

[kwired]

If they screw up they can always install a new piece of luan (thin veeneer) to the back with the hole in the right place. If a sheetrocker can do it then a cabinet guy should be able to.

Can and will are two different things.

 

[Dennis Alwon]

Dennis,
You answered this question a month or so ago about "hard wiring a DW." I was wondering why you coudn't put a box in the side of the cabinet, between the DW space and under the sink? In other words, side of cabinet under the sink next to DW space. I guess you would have to protect the wires in some way, but NM cable to a DW usually isn't protected in the ones I've seen.
Any thoughts on this set up?

Not sure where you mean. If you mean under the kitchen sink cabinet then sure you can. If I did that I would use carflex to protect NM. Some will argue that carflex is not listed for protecting nm but under a sink I can't imagine it wouldn't suffice. I always sleeve my nm to the disposal with carflex.

 

[LarryFine]

...t I've always purchased 6' of SO cord and a plug ...

I bet it would cost less to buy a 6' extension cord and cut off the socket end, not to mention faster.

We can't use just any dishwasher cord, it must be the 'right' dishwasher cord. :roll:

And the manufacturer's instructions must say so. Interesting that the NEC can mandate what must be written.

 

[goldstar]

I bet it would cost less to buy a 6' extension cord and cut off the socket end, not to mention faster.

You're probably right. At least the plug end would be factory made. The problem is getting a 6' cord that had a substantially insulated jacket. I certainly wouldn't buy a 25' commercial cord.

 

[busman]

Mark you are over thinking this. All you need to do is disconnect the wire in the box that goes to the dw.:grin:

Yes, I install a flush box but you certainly can install a surface box also.


If a cabinet installer can't get the cutout correct for a flush box then he has no business being an installer.

Just for the record. I over-think EVERYTHING, so nothing new here. As far as cabinet installers, I can't tell you the number that cut the hole the size of the flush box outline and make it impossible to get a cover plate on without cutting the hole bigger or using a box extension to put the cover flush with the cabinet back.

That's why I was thinking a 1900 box would be kinda fool-proof. Cover is the same size as the box and you could easily switch to a hard wire from one of the knockouts on the extension ring also. Just not sure it's the most sightly installation, but it's out of sight most of the time.

Thanks to all,

Mark

 

[Little Bill]

Not sure where you mean. If you mean under the kitchen sink cabinet then sure you can. If I did that I would use carflex to protect NM. Some will argue that carflex is not listed for protecting nm but under a sink I can't imagine it wouldn't suffice. I always sleeve my nm to the disposal with carflex.

Yes I'm talking about in the side of the cabinet under the sink. When you say "carflex" is that LFNC?

 

[wawireguy]

I just put appliance cords on the DW and the disposal. Both of these machines will need replacing some day and this makes the next guys job easier. It also is a cleaner looking install. I'm not going to worry if the cord is approved for that appliance or whatever. This is one area of the code I just ignore.