Can You Mix Different Gauges of Wire?

Every wire has a gauge; the gauge doesn’t represent the wire’s thickness only. It can control many of the wire’s properties like resistance, area, diameter, and capacity. Gauge is a very important factor to consider when building any electrical application. So, can you mix different gauges of wires?

Can You Mix Different Gauges of Wires?

No, it’s recommended not to mix different gauges of wires. However, in some cases, you can; it’s fine as long as the current passing through is not larger than the recommended gauge. The size of the wire and its resistance has an inversely proportional relation. Therefore a smaller wire means larger resistance.

So, if you are dealing with high currents, you must choose a suitable size. And in this case, you can’t mix different gauges of wire. NEC or the national electrical code doesn’t say something about mixing gauges. Nevertheless, mixing gauges can confuse in the future or mislead the inspectors.

Can You Mix 10 Gauge With 14 Gauge?

However, the ten gauge wire handles up to 30 amps when you connect receptacles or/and lights to the circuit. The limit goes down to 20 amps or less. Meanwhile, connecting the 14 gauge to any part of the circuit becomes limited to a 15 amp breaker.

Can You Mix 12 Gauge With 14 Gauge?

According to the code, the 14 gauge should be protected by a device that is not more than 15 amperes. Meanwhile, the 12 gauge can go up to 20 amperes. Therefore, a 15 amperes breaker can protect both of them well. But you should only use one of them; you can’t use them together.

Can You Mix 10 Gauge With 12 Gauge?

Connecting 10 gauge to 12 gauge is tricky; you can use a junction box and wire nuts. However, it will not be a safe connection. The 10 gauge needs a 30 amperes breaker, which means that the breaker will not work properly. Any fault in the 12 gauge will not be detected, which could lead to fire hazards.

Can You Increase the Gauge by Combining Wires?

Yes, you can increase the gauge by twisting the two wires together. So, each wire will pass the current’s half, which means increasing the gauge. The AWG cross-sectional area decreases as the AWG decreases, so if you have 10 AWG 20 wires connected parallelly, they can carry power as much as a single AWG 10 wire.

Another example, one single AWG 17 wire is equivalent to two AWG 20 wires. In the same way, the wire’s length has a relationship with its AWG. For example, the AWG 40 wire contains one ohm for each foot, the AWG 30 one ohm for every 10 feet, and the AWG 20 one home for every 100 feet. However, the parallel connection can work in DC well, but in AC, it may cause problems.

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What Does Wire Gauge Mean?

The gauge term means the wire’s thickness; each wire has a gauge and a number to represent it. Unlike most size numbering, in gauge numbering, the small number means a larger gauge or thickness; thus, the larger number means a small thickness. Originally, the gauge term AWG was found in America; AWG stands for American Wire Gauge.

It’s a method used to measure and identify the thickness of cables, especially the electrically conductive ones. It specifies the wires that are made out of non-ferrous materials. And non-ferrous means the alloys or materials that are pure of iron or ferrite. This method plays a vital role in determining appropriate wires for different applications.

To clarify, knowing the thickness of a wire is useful because the thickness controls other physical properties of the wire. Such as resistance and capacity of the wire. Which makes it easier for the manufacturer and the consumer.

How To Choose the Right Gauge?

Gauge is an important factor you should consider when forming an electrical application. It depends on different factors that you should keep in mind. For example:

  • Amperage Ratings
    A high ampere rating needs a thicker wire to bear the load and avoid any rise in the temperature. High temperature or heat can sometimes lead to hazards like fire or damage to the circuit’s components.

You should always avoid using too thin cables or wires because they can lead to failure. So, you can calculate the total amperes needed, the length of the circuit, and the load. Therefore, avoiding any problems in the future.

How Does Gauge Control Other Physical Properties?

The thickness of the wire or gauge can tell you a lot about the wire you going to use. The gauge has a direct relationship with many other technical specifications. For example:

  • Diameter
    The gauge number refers to the wire thickness, and it ranges from high numbers to low numbers. The high number means smaller diameters, while the small numbers refer to larger diameters. For example, the AWG 4 has  0.2043 inches in diameter, while the AWG 40 has 0.0031 inches in diameter. An interesting fact about the AWG is that every time it decreases by six-factor the diameter doubles.
  • Area
    You can calculate the cross-sectional area of any round wire through this formula A= πr2, while r stands for half of the diameter. The area is related to the AWG in an interesting way; every time the AWG decreases by 3 levels the area doubles.
  • Feet per pound
    The weight of the wire can be also determined through the AWG. For example, AWG 4 is 7.918 feet long which means it’s one pound in weight, while AWG 40 is 34.364 feet long and one pound in weight.
  • Resistance
    Any wire’s resistance depends on its thickness and its length. If thickness increases the resistance decreases, meanwhile, if the length increases the resistance increases. So, if you have the same length of wires but has different thickness or AWG, you can tell which one has the lowest resistance.
  • Capacity
    Every wire has a certain limit or capacity; it’s the amount of current that the wire can carry. As the thickness of the wire increases ( AWG decreases) the capacity decreases. You can think of it as water pipes; the larger pipe passes more water.

Different Wire Gauges Applications

AWG 4 Heaters and Furnaces
AWG 6 Cooktops for kitchen
AWG 10 Water heaters, Clothes dryer, and AC units (large)
AWG 12 AC units (small), Indoor outlets
AWG 14 Circuits, Appliances, and Light fittings
AWG 16 Extension cords
AWG 18 Low-voltage cords


To sum up, it’s not recommended to mix different gauges of wires. However, sometimes it can work without leading to any faults or damage. The main role to consider when mixing gauge of wires is to make sure the current passing isn’t larger than the recommended gauge. Increasing the gauge by twisting the wires’ ends together is doable.

You can always increase the gauge, however, it’s not recommended when dealing with AC. Because it can sometimes cause problems, Some applications use AC like audio and RF applications. Twisting the wires will mess up their characteristics.

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