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Discussion Starter #1
Hello...

I want to install a single junction box with a duplex 15amp receptacle. I want each half of the outlet(each plug in) to have its own 15amp circuit. I want to plug in an air fryer on one side or one half the duplex, and I want to plug in an electric griddle on the other half. Right now these are both on the same 20 amp circuit and will trip the breaker if both are turned on at the same time which is getting old.
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I am using MC cable as well. I was going to use a double pole 15 amp breaker. Can I break the tabs off the hot, and neutral or is this not allowed?
 

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You CAN do that.

However you need to do one of two things:

  • Feed the 2 circuits from a 2-pole breaker. Or
  • Feed the 2 circuits from 2 single breakers which are tied with an approved handle tie.
The approved handle ties can be a PitA to find, so I usually just suggest using a 2-pole breaker.

If GFCI is needed, you can either use a 2-pole GFCI or you can use two individual GFCIs with handle tie. Ditto AFCI (if you can find a 2-pole AFCI).

As long as you do the above, you also have the option of wiring it as a multi-wire branch circuit. In that case, you use a single /3 cable (instead of two /2 cables) and you share the neutral between the two half-circuits. However you can't do this with two 1-pole GFCI breakers. You also can't do it with two 1-pole AFCI breakers if the AFCI breaker requires neutral run through it.
 

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Is this in a kitchen serving the countertop? The requirements for kitchen receptacles serving the counter call for 20 amp circuits.
 

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Minimum complement of receptacles on a 20 amp circuit including a half of a 20 amp multiwire.:

One 20 amp, (with T shaped neutral slot).
Two 15 amp including separate halves of duplex receptacles with tabs broken.
One complete 15 amp duplex.
No receptacles at all, just a hard wired 20 amp load.
 

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A "Handy Husband"
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IMO, you would be better to install a 2 gang box with separate receptacles for each circuit.

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That box is not made to use with MC cable. You would need a meatal box, and I agree a 2 gang box would be better.
 

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While it may work to break the tabs and run two circuits on the same duplex receptacle, I would absolutely agree with the recommendation of going to a double gang box if at all possible. I don't know about the code requirements that is another issue entirely. I just don't like the idea of two dedicated circuit wires being separated by only the distance of the broken off tabs. I always thought the purpose of the tabs was only to make half the receptacle connectable to a switch for lighting purposes.
Also why MC cable? That box is designed for NM cable
 

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I just don't like the idea of two dedicated circuit wires being separated by only the distance of the broken off tabs.
You know, breaking off the tabs like that is standard procedure on multi-wire branch circuits. If it's wired correctly to not overload the neutral, there'll be 240V across the broken off tabs.

I don't know how it works so well, but I know it does, because UL approves it. If they were not satisfied it was safe to put 240V across the tabs, they'd require the tabs to be different.

I always thought the purpose of the tabs was only to make half the receptacle connectable to a switch for lighting purposes.
That's only one potential use for them.
 

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A downside of splitting a receptacle like this is that you can't use a GFCI receptacle (which are cheaper than GFCI breakers).
 

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Discussion Starter #10
Also why MC cable? That box is designed for NM cable
My house has what I think is called fire blocks in the walls. Each stud I have gotten into has a piece of wood running horizontal across it. They are never in the same spot either. I have given up on trying to run wire inside the walls. So now I use MC cable and run it on the outside of the house. When I am all finished with the electrical I am going to put new siding and foam insulation on the outside of the house which will hide all the MC cable.
 

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Discussion Starter #11
I have a seperate outlet now for my air fryer. It is 20 amps and on its own circuit. The picture with the black cover is the air fryer outlet.

I also have a dishwasher which is going to be on the GFCI outlet in the picture. Nothing else will be on this circuit, except for the vent hood and light which are both operated by the switch. It also has little buttons on the vent hood to turn on the fan and light. Note there is no ground on this circuit as it has old 2 wire romex with no ground.

I have an electric griddle, and a deep fryer that I am going to put on these two separate circuits I have been talking about in this thread.

So... I have managed to start on a double gang box which will run two separate outlets, but I want a switch for each appliance. I want to use an outlet that has a switch at top, and outlet at bottom.

Assuming I am going to use 12/2 MC cable.

Can I use a 15amp outlet switch combo here or must they be 20 amps?
(Since there is only one receptacle is why I ask)

Can I use a single pole breaker for each circuit here or must they be a Double pole breaker?
(Since two circuits will be in one double gang box is why I ask)

Also I hit a nice stud drilling my pilot holes for the sawz all so I will have to cut through one to put the double gang box in. No turning back now... There are two studs close by so cutting through one will not make much difference.

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A "Handy Husband"
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With a single receptacle on a 20 amp circuit, the receptacle needs to be 20 amp.

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^^ So would the switch - the OP wants all of his receptacles switched.

Without passing judgement on all the fried food involved, I doubt MC cable is rated for exterior use, but I suppose one problem at a time.
 

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I also have a dishwasher which is going to be on the GFCI outlet in the picture. Nothing else will be on this circuit, except for the vent hood and light which are both operated by the switch. It also has little buttons on the vent hood to turn on the fan and light. Note there is no ground on this circuit as it has old 2 wire romex with no ground.
You cannot have any receptacles on a circuit where the hardwired loads' nameplate adds up to more than 50% of circuit ampacity. That means the dishwasher will need to be cord-and-plug connected, but that is not allowed unless the dishwasher's instructions allow that.

You know, you can retrofit ground by running just a ground wire.

It doesn't even have to go all the way back to the panel; it only needs to go to a box that has an equal or larger ground wire going back to the panel.

I have an electric griddle, and a deep fryer that I am going to put on these two separate circuits I have been talking about in this thread.
That is a perfectly reasonable reason to have many kitchen countertop circuits. Note that more than 2 is a luxury, an optional choice of you to install. It's not required by law but that doesn't mean you shouldn't choose it.

Likewise the law requires my car have 4 tires. It doesn't require I have decent ones, but I am perfectly willing to.

Can I use a single pole breaker for each circuit here or must they be a Double pole breaker?
(Since two circuits will be in one double gang box is why I ask)
The restriction is per yoke. A yoke is that thing that has 2 receps (or it may have a recep and a switch). A 2-gang box can accept 2 yokes, so they don't need to be handle-tied as long as it's 1 circuit per yoke.

Anyone opening up a 2-gang box is expected to realize there's a probability that it's fed from 2 circuits.

Also I hit a nice stud drilling my pilot holes for the sawz all so I will have to cut through one to put the double gang box in. No turning back now... There are two studs close by so cutting through one will not make much difference.
Then surface-mount the box... it's all under the cabinet anyway, right? Heck you could've just left it at a 1-gang box and put a 2-gang extension on it...
 

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Discussion Starter #15
You cannot have any receptacles on a circuit where the hardwired loads' nameplate adds up to more than 50% of circuit ampacity. That means the dishwasher will need to be cord-and-plug connected, but that is not allowed unless the dishwasher's instructions allow that.
This is a 20 amp circuit there is no ground, but there is a GFCI. The dishwasher is 6.6 amps the vent hood is 2.0 amps so 8.6 amps total on this circuit both are hardwired The vent hood and light are both wired up to come on with a light switch although they both have little buttons on the actual vent hood to also turn on and off the light, and fan. So from your reply it looks like I am ok here, and don't need to do anything.

You know, you can retrofit ground by running just a ground wire.
I am not skilled enough to drill a hole through my wood walls and into the fire blocks in my wall which are small horizontal studs going from one vertical stud to another. I simply don't know how to get the drill and bit both inside there, and there is not enough room to come from the bottom since the bit would be way too long. I am sure there is a way to do it I just don't know how, and I am fine with several of the older circuits in my house not having a ground. I did use GFCI outlets and/or breakers as suggested here on this forum. Any circuits I have added of course do have a ground.

The restriction is per yoke. A yoke is that thing that has 2 receps (or it may have a recep and a switch). A 2-gang box can accept 2 yokes, so they don't need to be handle-tied as long as it's 1 circuit per yoke.

Anyone opening up a 2-gang box is expected to realize there's a probability that it's fed from 2 circuits.
Thank You very much for explaining that to me.

Then surface-mount the box... it's all under the cabinet anyway, right? Heck you could've just left it at a 1-gang box and put a 2-gang extension on it...
Sadly no it is above the counter. I could still surface mount it but it would look butt ugly right by the window with the curtain being so close. I don't mind cutting the stud, and coming out of the back of the house with MC cable.
 
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