Learning, Wiring,

Can I Connect Red and Black Wires Together (Guide)

Wiring can be a nightmare for DIYers. If you are a regular DIYer, there is a high chance that you often get confused about whether you can connect the red wire and black wire. You may have even erroneously combined them a couple of times. 

Knowing the right colors of wires to connect for a specific item is important, though it can be difficult if you are not an electrician. However, you do not have to worry. We have got you covered. Here is a guide on how to connect Red and Black wires.

Can I connect black and red wires? You can only connect black and red wires if they are insulated. If they are not and the copper surface of the two wires comes into contact, it may cause circuit failure or burning of the wires.

How to Use Red and Black Wires

Black and red wires are live wires and are usually not connected to the same ports. A black wire goes into the phase 1 terminal while the red wire goes into phase 2, but you should not connect them on the same terminal. 

In some cases, especially where there are higher voltage circuits, you can often find both black and red wires. In that case, the black wire becomes a negative while the red becomes positive.

Let us look at how to use black electrical wires with red wires for different scenarios.

For a Plug

Both black and red wires are always connected to different terminals in a plug. The red one is usually for the light kit on the plug.

plug terminal

For a Phone Charger

Just like for a plug, both the red and black wires are connected differently for a phone charger. You have to connect both to different terminals.

USB wire peeled and cut

For a Ceiling Fan

A ceiling fan has a single circuit. That means they can only take a single wire. In this case, you have to connect the red wires to the light kit while you connect the black wire to the fan to get your appliance working.

technician fixing the wire of a light fixture

For a Car Battery

When it comes to your car battery, you also have to connect them separated. Both the red and black wires should not be used on the same terminal.

car battery

So, can I connect red and black wires at any point? Let’s establish this fact. Yes, you can connect the red and black wires if they are insulated. You can also connect both wires if you want to achieve lower voltage. You should exercise caution in this case, however. 

Connecting black and red wires to get a lower voltage can create higher voltage in the long run and this can burn your wires later. Therefore, it is best to connect them on different terminals.


Are red and black electrical wires the same?

Both black and red wires are the same but the exterior insulator color is different. Apart from the colors, a black electrical wire and the red version are both live wires. The black wire is used for current flow while the red color is for the negative. 

Both wires work as a circuit in a DC circuit and that is why they are usually connected differently. The black is the negative charge and the red is the positive charge. Both offer flowing current into any appliance. 

It is recommended that you connect the wires based on the instructions on your device and make sure to connect them using a cap. It is important to ensure that wires are connected with a cap before you connect many wires at the same time. This is to avoid higher voltage and the danger that comes with it.

Can you pigtail red and black wires?

Yes, you can. You can pigtail black and red wires if both wires are correctly connected. Black and red conduct current in different phases. Both should be connected on different terminals as having both connected to the same source would do no good. 

As mentioned earlier, connecting both can increase the voltage and ruin the neutral wire in the process. However, if both wires are connected to the right port, you can pigtail them in a box. If you are not sure that they are connected to the right port, they should be insulated. If not, they can fry or cause a short circuit.

What happens if you connect a black wire to a red wire?

The fact that black and red wires are live wires cannot be overemphasized. Connecting both can cause harm in most cases. It is best to leave them separately after using a cap or it may become a disaster. Here are some possible scenarios you can experience when you connect black and red wires:

High Voltage: 
Both colors of wires are hot wires. One conducts current to the circuit and the other conduct the current to the switch. Connecting both is not a smart decision because the total voltage you get from the combination will increase the circuit. With this, the differences will increase and the flow of electricity will surge. This may cause a short circuit. (1)

Burn Neutral Wires: 
It has been established that connecting black and red wires together will cause high voltage. This may result in burning your neutral wires. As the higher voltage passes through, the neutral wires can get damaged and result in a breakdown of the circuit.

Conduct Current Through You: 
Both wires complete the circuit. If you connect both, the combined wires may assume that the person holding the wires is the conduct and cause the conducted current to go through. This may cause an electric shock, which could be fatal, depending on the strength of the voltage.

How to connect black and red wires?

You can connect black and red wires in the circuit with your preferred wires, such as a white wire. However, you should not connect both black and red wires. Many people do this when they are short of extra wires and cannot find any. If you find yourself in this situation, here are things you can do:

Screw off the switch:
The first thing to do is to take off the switches. You can also take off the wire before you turn off the circuit and then continue with your process.

Connect the Wires to the Circuit: 
Before you connect the wires, scrape off a bit from the insulating portion protecting the wire. Next, connect the wires based on the color codes. Connect your black wire to the one with the black code and the ground wire to the ground one.

Next, connect the red wire to the light kit. If you do not have a red wire in the circuit, consider connecting it with another one. Make sure to use a cap to insulate the wires.

Turn the Circuit On: 
Once you have connected the wires, put them into the switch box and then screw the box. With this, the circuit is full and you can turn on the switches.

Can you connect different colors of wires?

Yes, you can connect different colors of wires. However, this may not apply in all cases. You should only connect neutral wires. You need the neutral wires in the circuit to control the current imbalance and flow the current into the ground wire state. 

As you may already know, blue and red wires flow current through a circuit while neutral wires take the current flow right to the ground state. This reduces the current load in the circuit. (2)

What colors of wires go together?

The Gray and green colors go together because they are both neutral. It is worth mentioning that not all wires can pair together. Only grounded or neutral wires can go together. Red and black wires should be separated because they are both live wires.

Wrapping Up

Electrical wiring requires a good understanding of the different colors of wires and how each pair with the other. You should not connect red and black wires, even though some people may want to. It is best to connect them separately to avoid causing damage to the circuit.

Take a look at some of our related articles below.

(1) electricity surge – https://electronics.howstuffworks.com/gadgets/
(2) current flow – http://www.csun.edu/~psk17793/S9CP/

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About Sam Orlovsky

AvatarCertifications: B.E.E.
Education: University Of Denver - Electric Engineering
Lives In: Denver Colorado

Electrical engineering is my passion, and I’ve been in the industry for over 20 years. This gives me a unique ability to give you expert home improvement and DIY recommendations. I’m not only an electrician, but I also like machinery and anything to do with carpentry. One of my career paths started as a general handyman, so I also have a lot of experience with home improvement I love to share.

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