What Happens If You Connect White Wire to Black Wire? (Electrician Speaks)

Today, you’re going to learn about the outcomes of connecting a white wire to a black wire for general electric purposes.

Connecting black (hot) and white (neutral) wires can cause many problems. You might do it accidentally or intentionally. Either way, I can tell you from experience that it can be dangerous if not done correctly.

In general, you are allowed to connect black and white wires together in a switch loop. Apart from that, connecting these wires can cause the following issues.

  • Connecting the bare wires while the power is ON will create a big spark in the wires. Also, this will blow up the fuse or trip the breaker.
  • If you turn ON the power after connecting the hot and neutral wires, the spark will occur at the fuse or the breaker.

I will go into more detail in the article below.

When is Connecting White and Black Wires Safe?

Even though connecting black and white wires is a dangerous thing, in some instances, you might see these two wires connected.

Safe Scenario: What is a Switch Loop?

There is no need to get confused. Electricians connect the black and white wires when wiring a switch loop. The black wire signifies the hot wire, and the white wire is the neutral wire. However, not all white wires can be categorized as neutral wires. For instance, in a switch loop, the white wire acts as the hot wire. Thus, connecting white and black wires together won’t cause any issues.

A switch loop is another way to describe the connection between the switch and the light. Simply, it allows you to turn ON and OFF the light without removing it. A switch loop turns the neutral wire into a hot wire. So, in a switch loop, the black and white wires are hot.

Be mindful: In a switch loop, the white wire also acts as a hot wire. So, you are connecting two hot wires. Only the colors are different.

Dangerous Connection 1 – When the Power is ON

short circuit diagram

Sometimes, you might connect bare wires (white and black) together while the power is ON. It could be an accident, or you might do it intentionally. But the result could be dangerous.

large spark
Video | Tech Stuff

When you touch the two wires together, it will create a large spark immediately. Also, the short circuit situation will blow a fuse or trip the circuit breaker.

Be mindful: You should never intentionally connect the black and white wires. There is no need for such reckless behavior.

Dangerous Connection 2 – When the Power is OFF

If you connect the white and black wire while the power is OFF, the outcomes will be slightly different. Most of the time, you might accidentally connect a white wire to a black wire during the wiring process.

However, the result will not be good when you turn ON the power. Here, the sparks will occur at the circuit breaker or the fuse instead of in the wires. Also, it might trip the breaker or blow the fuse.

What We Learned So Far

As you understand, you should never connect the black and white wires unless you are wiring a switch loop. Both wires are hot in the switch loop, but the colors are different (black and white). So, follow these guidelines while wiring a light fixture, switch, or outlet at your home.

What to Do if Black and White Wires are already Connected?

If you go through the above sections, you now know the results when connecting a hot wire and neutral wire together. But do you know how to act if you detect such a connection?

incorrect wiring of two white wire
Video | HelpingHand

Sometimes inexperienced electrician can mess up the wiring process, or you might wire the circuits incorrectly. Whatever the reason, you should be careful while handling such a situation.

As per my knowledge, there are two solutions for this.

Solution 1. Installing New Light Fixture

For this demonstration, assume you are planning to install a new light fixture.

The target is to connect the hot and neutral wires correctly to the new fixture.

non-contact voltage tester
Video | Flannel Guy DIY

  1. First, turn OFF the power and carefully loosen the wires from the old light fixture.
  2. Then, turn ON the power. Take a non-contact voltage tester or digital multimeter to identify the hot and white wires correctly.
  3. Next, turn OFF the power again. The black wire should be the hot wire. If the white wire is the hot wire, use black tape and wrap it around the white wire. Or mark the wire using a black marker pen.
  4. Finally, wire the new light fixture correctly.

You can follow the same process for outlets and switches. However, try to identify the polarity of the wires correctly.

Solution 2. Hiring a Professional

If you aren’t comfortable with the above process, don’t hesitate to hire a professional. An experienced professional might bring experience that can be invaluable for your particular situation. (1)

short circuit - wire in fire

Be mindful: Following the proper electrical safety, precaution is crucial for your home. Even the tiniest thing can turn into a disaster. For instance, connecting a white wire to a black wire could start an electrical fire. (2)

FAQs

Can Both White and Black Wires Be Hot?

Yes, it can happen. If you are wiring a switch loop, you’ll have to connect the white wire to the black wire. Hence, the white wire becomes a hot wire.

Also, some electricians might use a white wire instead of the black wire by mistake. So, in such situations, both black and white wires are hot. First, check the polarity of the wires and confirm this issue. Then, take the necessary action.

Is It Okay to Connect a Green Wire to a Black Wire?

No, it isn’t. The green wire is the ground wire of a circuit. It should be grounded. The black wire connects to other black wires, not the green wire. In some electrical circuits, you might find a bare copper wire as a ground wire instead of a green wire.

How Can I Check the Polarity of a Wire?

First, use a non-contact voltage tester.

– If the tester light is ON, the wire is hot.
– If the light is not ON, the wire is neutral or ground.

If needed, you can use a digital multimeter. Set the multimeter to voltage mode and take the reading of each wire. The wire that shows the reading close to 120V is the hot wire.

If the multimeter doesn’t show any reading, that wire is the neutral wire.

Wrapping Up

Connecting a white wire to a black hot wire is not a good thing at all. Even if you are doing it for testing purposes, I wouldn’t recommend it. Doing such a thing can risk the safety of your home.

Take a look at some of our related articles below.




References
(1) Hiring a professional – https://www.businessnewsdaily.com/15752-employee-hiring-guide.html
(2) disaster – https://www.ifrc.org/what-disaster

Video References

Mihai P

Benjamin Sahlstrom

Tech Stuff

HelpingHand

Flannel Guy DIY

About Sam Orlovsky

b1d87d2ee85af3e51479df87928bdc88?s=90&d=mm&r=gI realized early on carpentry was a huge passion for me and I’ve stayed in the industry for over 20 years now. This gives me a unique ability to really be able to tell you what the best tools and recommendations are. I’m not only a carpenter but I also like machinery and anything to do with electrics. One of my career paths starting off was as an apprentice electrician so I also have a lot of experience with electrical products and anything related.