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AssuredElectrical, Master Electrician
Category: Electrical
Satisfied Customers: 4241
Experience:  Contractor-42+ Years in the ElectricalTrade
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Dishwasher and Garbage Disposal Connection The outlet under the sink has two receptacle

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Dishwasher and Garbage Disposal Connection

The outlet under the sink has two receptacles: supposedly one for dishwasher and one for garbage disposal. However there is only one power line enter the outlet box (4 wires: red, black, white and ground wire). The current connection only has one receptacle work: the garbage disposal works fine, which has a wall switch, which works fine too (i.e., it turns the garbage disposal on and off). However, the other receptacle has no power. How do we fix this so the garbage disposal stay the same and dishwasher has the power (should be always on)? I am expecting detailed wiring instruction. Solution that requires wire change in the wall (e.g., install a new wire from the wall-switch to the outlet is not acceptable answer since I know that will work).

Welcome. My name is XXXXX XXXXX would be glad to assist.

To better assist, a item to determine what the problem may be.

Do you have a 2 lead voltage tester?

Is there 2- duplex receptacles (4 plug ins) or just 1- duplex 2 plug ins)?


Is the breaker for these a 2 pole or single pole breaker?


Customer: replied 3 years ago.

Yes, I have a multimeter and can do various tests.


Here is only 1 duplex receptacle (with 2 plugins: one for dishwasher and one for garbage disposal).


The breaker is 2 poles (and the handles are tied together).

One thing I noticed is that the wires on the breaker: one is red and one is black. Should it be all reds for both poles?

There would be a red and black on the circuit breaker.
That is whats called a split circuit. Used in some applications such as this.

The breaker is required to be a double pole, so that both circuits trip if only one encounters a short.

This is because they share the same neutral, so this keeps the circuit in check to eliminate a high voltage spike.

Customer: replied 3 years ago.

I checked the breaker. Both wires (red and black) have power (120v). However, in the switch box, only the red wire has power. The black does not have power. What does this tell us? The connect from the panel to the switch box has issue (that is, the black wire has a broken connection some where from the panel to the switch box)? If so, how to fix this?

Thanks for the test.

Did you test red to ground and then black to ground? Only red had 120 volts at the switch box?

Test the breaker with red to black and be sure it is 240 volts.
Dont test each one to ground at the panel.

If so, and the breaker has 240 volts leaving, then there must be a junction box between the breaker panel and the switch.
If you can trace the cable from the breaker panel, you may find the junction along the way.

Without seeing the cable run, it would not be possible to determine where the junction may be.
Junction boxes could be mounted anywhere along the run.
It all depends on how the house is built and location of panel and kitchen.
There are no rules to where to locate them except they must be accessible for troubleshooting in cases like this one.

Is it an open basement where the panel is located?
Customer: replied 3 years ago.

Yes, all my previous tests are against the ground. Yes, only red has 120 volts at the switch box. Yes, the breaker has 240 volts between the two poles.


The panel is in the garage, which is only about 20 feet away from the sink (direct line distance). The cable is inside the wall.. how do I trace the cable?


Is there any tool to help trace the cable without open up the dry wall?


I found the following from the internet:

"The device I am thinking of attaches to the wires at the breaker panel and emits a high freq signal. Trace the signal with a portable reciever and when you lose signal, backtrack about a foot and you'll fine the end of the wire. MAKE SURE you turn off the main breaker before attempting this."


Do you such device? What is its name? Thanks.



They make locator's, yes. But honestly, you can easily have an electrician out and install a new line for much less than the cost of one.

Locater of that type is $500-$700 for in wall tracing.

Being only 20 ft from the panel, I would not suspect any junctions on the circuit unless the home is older and has been through some remodeling at some point.
The cable probably runs through the attic and then down the wall to the receptacle.

I would turn off the breaker and visually inspect the individual black wire at the panel and the switch box.

I have seen many times wires being stripped at the termination point and then made up, only to break the wire inside the insulation.
So, power cannot pass any longer even though it appears to be intact.

Check all terminations and actually undo and re strip the wires and then reconnect them.

Check where the cables enter the box and panel also, sometimes they are broken at the entry points but not near as often as at the connection points.

Verify that there are no other receptacles on that breaker by turning it off and test all in the area.
There could be one on the circuit and only be a loose connection in the receptacle which is the #1 most common problem.

Fluke Makes an in wall tracer #2042 for your reference. <Click There
Customer: replied 3 years ago.

Thanks for the suggestions. I got an electrician in. He said the wire may go along the cabinet wall (along the kitchen) and it is hard to lay a new line (since there is no attic due to second floor). So he suggest to use the red line to power both the dishwasher and the disposal.


Do you think this is a safe, and building-code compliant?

It definitely could run around the wall. In those cases, it is possible to run conduit on the outside of the house if both the panel and receptacles are on the outside walls Just a possible suggestion.

The disposal is used intermittently , so normally should not be any issues.

The only issue would be the load.

Together they do not need to exceed the circuit capacity.
You would have look at the nameplates on both and then determine the amperage on the circuit.

If it is a 20 amp circuit, it most likely is fine.
A 15 amp would be too small for both most likely, as disposals are around 7-8 and dishwasher the same when the heating element is on.
AssuredElectrical, Master Electrician
Category: Electrical
Satisfied Customers: 4241
Experience: Contractor-42+ Years in the ElectricalTrade
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