What happens if the wire gauge is too big?

Are you working on an electrical or electronic connection? Then you’ll want to know the different sizes of wires available and which one is appropriate to use. So, what happens if the wire gauge is too big?

Wire gauge describes the wire thickness. Although using a bigger wire gauge reduces voltage loss, it’s not advisable. There are a few cons, such as the higher costs, the effect on the appearance and weight of the connection due to limited space, and the likelihood of affecting high-speed signals.

However, when a wire is too small, it can melt and start a fire under some conditions. So, it’s important not to use a wire gauge below the required size for a connection. Here, we discuss what happens when the wire gauge is too big.

What is a Wire Gauge?

Wire gauge is the measurement of the wire diameter and generally describes its thickness. The wire gauge determines its weight, current capacity, and resistance. Numbers represent wire gauges, and the lower the number, the thicker the wire. The major advantage of using bigger wire is less voltage drop. A bigger wire will carry more current over any given distance than a smaller wire.

Thicker wires have less resistance which is responsible for the lower voltage drop. The thinnest wire, the more resistance it has. It’s this resistance that leads to voltage loss. Even though the wire is too big, it won’t cause any overload or affect anything per se.

Types and Applications of Wire Gauges

Here are the appropriate wire gauges for the different electrical connections you might be setting up:

  • Gauge 18: For low voltage cords and lighting or remote lead turn-on wire
  • Gauge 16: For extension cords with a small load and short power runs below 50 feet
  • Gauge 14: For lighting devices, circuits, and fixtures
  • Gauge 12: For small air conditioning units and power outlets and long wire runs or any high power application
  • Gauge 10: For water heaters, big air conditioning units, and clothes dryers
  • Gauge 6: For ranges and cooktops
  • Gauge 4: For large heaters and furnaces

How Do You Determine Wire Gauge?

American Wire Gauge is the standard of measurement for electrically conductive wires. It ranges from 40, which carries a maximum of 0.0137 amps, to 0000, which can carry 302 amps. The diameter plays a significant role in determining the wire gauge. There are two ways to determine the gauge of the wire. They include:

1.  Using a Wire Gauging Tool

If it’s an insulated wire, you can’t tell the gauge until you strip it. So you might want to get a wire stripping tool to remove the insulation from small parts of the wire, around 2 inches. Three tools usually have several holes of different gauge sizes. You need to put it in the hole where it fits and strip off the insulation. Then you can measure the gauge of the stripped part.

When it’s solid wire, you don’t need all the stripping. You can get a wire gauging tool, a circular metal piece with holes for various gauge types. There are holes for all gauge sizes on the perimeter; you have to put it in the one that fits. Make sure you get a gauge tool matching your measurement system.

In the case of stranded wires, you need to measure the diameter of one of the strands and multiply it by itself. Then use that result to multiply the number of strands. Generally, larger gauge wire will have fewer strands than the small gauge ones.

2.  Calling the Manufacturer or Visiting Your Hardware Store

You can also opt to call the manufacturer of the wire to determine the gauge. Ask your neighborhood hardware store if you can’t find the number. The person in charge will guide you. You must know the wire gauge before you start work.

Cons of Using Thick Wires

Most times, nothing bad will happen if you use thicker wires. It’s just unnecessary and may not have any benefit. Although there might not be any direct harm from using a wire gauge that’s too big, it has some disadvantages. They include:

1.  High cost

The cost of wires depends on the size of the gauge. So, if you use a wire gauge bigger than what you need for a connection, you’ll be spending more on the cost. The cost will also include the need for bigger pathways and the size of the clamp or terminal it connects to. All of these will have to be bigger.

2.  Heaviness and Effects on Appearance

The size of the wire gauge also influences the weight. So wire gauges that are too big automatically mean the electrical or electronic system will be heavier than needed. From a mechanical viewpoint, bigger gauge wires might not be advisable because they’ll be too much for all the terminations, such as screw terminals, crimp terminals, and others.

3.  Affect High-speed signals

If you’re running a high-speed signal through the wire, thicker wires have more capacitance. This might make it become a low pass filter which isn’t what you want. As a low pass filter, the signal will be lower than the ideal frequency.

Should you Use a Bigger Wire Gauge

Sometimes, you might feel like using a bigger wire gauge, so you’ll get better quality. This isn’t necessary. The gauge shouldn’t be your priority if you want to spend extra money on a wire. Instead, focus on the strand count, insulation quality, and durability, and make sure it’s designed for the use you have in mind. Given the way that people use power outlets with extension cords, it’s also advisable to use thicker wires for power outlets. It’ll save you any safety troubles.

Can You Connect Two Different Wire Gauges?

It’s possible to connect a 14-gauge wire to a 12-gauge wire, but then you’ll have to use a small amp for the circuit breaker or fuse, preferably a 15 amp. Connecting it to a larger capacity breaker like 20 amp could result in the 14-amp wire overheating and catching fire.   This is why it’s not advisable to mix the sizes of wires. Best to stick with one size and use all through.

When connecting wires, it’s important to ensure that the wires match the circuit breaker. So, use 14-gauge wire for a 15-amp circuit breaker which is what most lighting circuits use. However, if it’s a circuit controlling power outlets, you should use a 20 amps breaker with 12 gauge wires instead.

In Conclusion

There’s no serious harm in using a wire gauge that’s too big. It might just make your work costlier and harder. But it could also have advantages. Still, the real danger is using a wire that’s too small rather than one that’s too big.