Learning, Wiring,

Can You Use Two Different Gauge Wires Together (Tips & Breaker Sizes)

I have put together this short article for those looking to splice two different gauge wires.

In general, you can connect two different gauge wires. But you must follow one guideline. The breaker or fuse should match the smaller gauge wire. Otherwise, the small wire will get overloaded.

Continue reading below for more details.

Is It Possible to Connect Two Different Gauge Wires?

Yes, you can connect two different gauge wires. But you should follow one important guideline.

The fuse or the circuit breaker should match the smaller gauge wire. Otherwise, the small wire will get overloaded. And it could damage or melt the small wires. Sometimes, it could start an electrical fire. I’ll talk about these consequences later in the article. For now, follow the below example to understand the small wire and circuit breaker dilemma properly.


Identifying The Smaller Wire

Assume you are trying to connect 12 gauge wire and 14 gauge wire. First, you should be able to identify the small and large wires. If you have doubts about these sorts of things, read the following section carefully.

When the number of wires increases, the wire’s size decreases automatically. That means the 12 gauge wire is thicker than the 14 gauge wire. In other words, the 14 gauge wire is the smaller wire.

Tip: If you use 16 gauge and 14 gauge wires, the 16 gauge wire is smaller.

Determining the Correct Circuit Breaker

After identifying the smaller wire, you can determine the correct circuit breaker size. Use the information in the below table for that.

Wire GaugeBreaker Size
16 gauge13 amps
14 gauge15 amps
12 gauge20 amps
10 gauge30 amps
8 gauge40 amps
6 gauge55 amps
4 gauge70 amps
3 gauge85 amps
2 gauge95 amps

According to the above information, you can decide the breaker size for this example circuit. But remember, as I said earlier, the breaker size should match the smaller wire.

That means you should choose a breaker for a 14-wire gauge. And for 14 gauge wire, you should use a 15 amp circuit breaker.

When using a 15 amp breaker, the electricity won’t damage or melt the wire since the 14 gauge wire can handle 15 amps easily.

What Happens If You Use a 20 Amp Circuit Breaker?

Some might use 20 amp circuit breakers when they use 12 and 14-gauge wires together.

Here’s what happens when you have 20 amp breakers on 12 and 14-gauge wire connections.

The wire will get overloaded when using a 20 amp breaker on a 14 gauge wire. This electricity overload will melt the wire insulation. This melting can lead to an overheating of the wire conductor, which might eventually start an electrical fire.

Indications of Overheating Circuits

Knowing the signs of an overheating circuit will save you from property damage and accidents. So, here are a few signs that you should look out for.

Note: You might experience one or more below signs if the circuit breaker size is not matched with the smaller wire.

  • Dimming light indicates a circuit overload, especially if the dimming occurs when you turn on more appliances.
  • The switch and outlet cover become hot when you turn them on.
  • Buzzing switches and outlets
  • The burning odor from outlet and switches.
  • Lack of power to the appliances, power tools, or electronics.

Few Simple Steps to Connect Two Different Gauge Wires

You should learn the correct technique if you are set to connect two different gauge wires. 

Things You’ll Need

  • Suitable crimp connectors
  • Crimping tool
  • Wire stripper

Step 1 – Remove the Insulations

First and foremost, remove the insulations of both small and large wires. Use a wire stripper and remove the wire insulation’s 0.25-0.5 inch length.

Tip: Turn off the main power supply before messing with electrical wires.

Step 2 – Crimp the Wires

Then, take a suitable crimp connector and insert the two wires. Depending on your wire size, you’ll have to use different-sized crimp connectors.

Now take the crimping tool and tighten the connection at the crimp connector.

Can I Solder the Two Wires?

Yes, you can use the soldering method to connect two gauge wires. It is undoubtedly one of the most reliable ways to splice two wires. However, you might need some practice with a soldering iron, and wrong execution might lead to poor connection.

Video References

Electrical Code Coach

Make It Easy Mechanic

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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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