Light switches have different colored wires connected to them. These colors actually represent different meanings as well as serve different purposes.
While you might have seen that every light switch has one wire of different color mounted on them, however, some light switches have two black wires. Therefore, in this article, we are going to find out the reason why light switches have two black wires.
Why does my light switch have two black wires?
One of the main reasons that your light switch has two black wires is that one black wire supplies the current, and the other one receives the current. One black wire is attached to the line side of the new outlet from the supply side and the other one is attached to the load part of the outlet.
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There are several reasons behind the electric switch getting mounted up with two black wires. The wires are used to supply and receive current from another source.
From the two black wires, you might notice that one black wire is hot and the other is cold. That means the hot black wire receives power from another outlet and passes it onwards. The neutral wire also has the same purpose.
Most of the light switches have two black wires and two white wires. But they do also serve the same purpose just like the two black wires. From the two black wires, one acts as neutral and the other one is the hot one.
Similar to that, in the case of the two white wires, one acts as the hot one and the other one as the neutral one. In most circuits, this sort of wiring is found if the outlet is set up in the middle of the series circuit.
Because in the series circuit, the wires are mounted up to accept power from another source and pass it onwards.
The two black wires are used in almost all switches in the U.S.A. The usage of two black wires ensures that there is no overload in the outlet as well as makes sure the currents pass smoothly and safely.
Can you have two black wires on a light switch?
Yes, you can have two black wires on a light switch, and in fact, using two black wires saves your outlet from overloading and short circuits.
You may also notice some of the light switches have different colored wires. Therefore, we have discussed whether any light switches can have different color wires in the below segment:
Two black wires only:
Well, most of the light switches have two black wires in order to ensure proper passage of current from another source and definitely you can have them in your light switch.
Two black wires usually indicate that one black wire is the hot one and the other one is the neutral one. Usually, the hot one receives current from another outlet passes it onwards and the other one remains the neutral wire.
Two black wires and one white wire:
Yes, you can have two black wires and one white wire in an outlet. However, the white wire will be represented as the neutral one and both the white wires will carry the current from another outlet.
Two black wires and two white wires:
Well, just like the two black wires mounted outlet, the two black wires, and two white wires switches are also common and most used combination in a light switch.
However, don’t think that the two black wires are not used as the current receiver rather one of the black wires is used as the current receiver from another circuit.
While the other black wire is used as a neutral one. Similarly, one of the white wires is used as a current receiver from another circuit and the other white wire is the neutral one.
Two black wires and one red wire:
In a 2-way switch two black wires and one red wire is used. The red wire is used as the load and one of the black wires is used as a current receiver from another outlet and the other black one acts as the neutral one.
Two black wires and one green wire:
It’s completely normal outlets having two black wires and one green wire.
One of the black wire receives the current from another outlet and passes it onwards while the other black one act as the neutral. The green wire is used for the grounding.
Does it matter which black wire goes on a light switch?
Actually it depends, because only in the case of single-pole, it doesn’t matter whether which black wire goes on a light switch. Because one of the wires goes to the power switch and the other black one goes to the light.
Well, sometimes, some outlets have two black wires and if that outlet is not a single pole then the two black wire is used as the hot one and the neutral one.
But above all make sure you have taken all safety measures before reversing the wires on a light switch. Make sure to check out if the outlet is a single-pole outlet with two terminals.
What happens if you reverse the wires on a light switch?
Well, reversing the wires also means that reversing the polarity which is dangerous. Because in the case of reversed polarity the hot wire is usually is set on the neutral side. In the same way the neutral wire is also set on the hot side.
If you connect a bulb or lamp to a reversed outlet then the lamp will receive power even its switch is turned on. In addition, if you touch the lamp in this situation then you might get electrocuted.
Therefore, reversing the wire on a light switch is very dangerous and you need to be careful before doing that.
Among the 2 black wires on the light switch, which one is hot?
Identifying the hot wire from the two black wires is very easy. You have to just follow our simple steps in order to identify the hot one from the two black wires:
Put on gloves:
First things first, you will need to put on rubber gloves or anti-shock gloves. Because touching the hot wire might give you an electric shock.
Make sure your multimeter is ready:
You have to make sure that your multimeter is ready to measure the voltage. Now place the red wire that comes from your multimeter on the metal of the hot wire.
Don’t get confused with the wire coloring as the red wire that comes from the multimeter is positive and the black wire on the outlet acts as negative.
Place the multimeter’s black wire on the white wire:
Now you have to place the black wire that comes from the multimeter on the bare metal of the white wire.
Then you have to check the multimeter and if there is reading then the black wire is hot. Otherwise, it’s not.
Repeat the test:
If the result turns out negative on the first black wire then you have to repeat the test on the other black wire. If there is a reading on the multimeter then that black wire will be the hot one.
How do you wire a light switch with two black wires?
Well, wiring a light switch with two black wires is a very complicated process. But you can do it very easily by following our below steps:
Turn off the power source:
First thing first you have to make sure that there is no electricity passing through the circuit. You have to turn off the main power source and for safety reasons double-check the switches with a tester.
Remove the switchboard:
Now you have to carefully remove the old switchboard. After removing the outlet you will notice that there is a wire layout with two black wires and two white wires as well as other green and copper wires.
Remove the wires:
Now you have to remove the black wires that are connected to the screws which are known as terminals. Then you have to carefully remove the grounding wire which is green colored.
Connect the wires:
Now you have to connect those wires to the new terminal screws as well as the ground screws of the new switch.
Make sure with the help of pliers you connect the wires tightly to the terminal screws and screw the screws to the switch outlet.
Testing:
After completing all the above steps now it’s time to check your new mounted light switch.
Final thoughts
The light switches can have two black wires as well as two black wires and two white wires. Regardless of the number of black and white wires, the main purpose of these wires is to receive the power from an external source and supply the power onwards.