Can You Put a 30 Amp Fuse in a 20? You Should Know!

It is recommended that you do not use a 30 Amp breaker in favor of a 20 Amp breaker since the wiring is most likely “sized” for a 20 Amp load and may overheat if a 30 Amp load is used with wiring that was initially designed for a 20 Amp load, according to the answer.

It is your safety device, the fuse that protects you. Always use the larger fuse when replacing the smaller one. It has happened before, and people have lost their homes due to their actions. To increase the current through the wire by 50%, the wire must be overheated, resulting in a fire if it is not done correctly.

Please keep in mind that the fuse keeps the wiring from becoming too hot and setting on fire. On 12-gauge wire, a 20-amp fuse is used, while on 10-gauge wire, which must be larger, a 30-amp fuse is utilized. Do not combine the two. If you’ve taken any electrical course, it’s best to use a larger fuse.

Changing a 15-amp breaker to a 20-amp breaker

Changing a 15-amp breaker to a 20-amp breaker

The task of upgrading a 15-amp breaker to a 20-amp breaker can be accomplished relatively quickly, but it should only be done if the AWG wire is the appropriate gauge wire capable of carrying the required current.

It only takes a few essential tools and a replacement breaker to complete the job successfully. For example, if the branch circuit is made up of a 14-gauge wire, you’ll need to run a new 12-gauge wire before installing a 20-amp breaker in the electric system and a 20-amp outlet at the end of the circuit without causing damage to the wiring.

How to change 15-amp breaker to 20-amp breaker


Essential products

  • Switch the main supply off
  • To be safe

Check the Fuse box from Amazon.

  • Open the breaker panel
  • To help you check the inside of the breaker box

Flathead screwdriver

Insulating gloves

Circuit breaker

  • Ensure your gauge is correct
  • To know what wire is best to use

14-gauge wire

  • Release the old breaker
  • To replace with the new one



Contactless voltmeter

  • Fit the new breaker



Step 1; Switch off the main power supply

Working with no current flowing through the fuse box panel is always safer. Before accessing the panel, be sure that the main power switch is turned off.

Check the fuse box from Amazon.

Step 2; Open your breaker panel

Put on insulating gloves and then use a flat head screwdriver to pry the cover off the circuit breaker panel box from its mounting bracket. Holding the cover plate in position with one hand while removing the last screw will keep the cover plate from sliding when the final screw is removed from the cover plate.

If you want to know the screwdriver I use, check the flathead screwdriver from Amazon.

Step 3; Ensure that your gauge is correct

Check the wire gauge on your circuit where you wish to install a new breaker before proceeding. If you have a 14-gauge wire, often known as #14 AWG, in your circuit, you will be unable to use a 20-amp circuit breaker.

If you choose to proceed with the change, you will need to use 12-gauge wire to substitute the branch circuit wiring that was previously installed. Installing a 20-amp circuit breaker on a 14-gauge wire will violate the National Electrical Code and constitute a serious safety hazard to your family’s safety.

The 14-gauge wire is 0.06 inches thick, whereas the 12-gauge wire is 0.08 inches thick if you’re unsure how to identify the difference between the two-wire gauges. On the outside wire sheathing, you can see the gauge wires that have been used. You can use the new 20-Amp breaker to manage the circuit load if you confirm the suitable wire size.

Step 4; Release your old breaker

Use your headlamp to provide additional lighting for this step, especially if the breaker box panel is located in a dark area. Make sure that none of the cables carry any current using your multimeter or contactless volt-meter.

Undo the screws holding the cables in position on the breaker and slide them to the side so that they are out of the way. Circuit breakers are either clipped or screwed onto the circuit box panel casing, depending on the breakers.

Step 5; Fit in your new breaker

Install the new circuit breaker by clipping or screwing it into place, and then link the wires to the new breaker. After the cables have been connected, turn on the main power switch and the circuit breaker for your new device.

Test the voltage across all circuit breakers using the multimeter to determine that the voltage across the replacement breaker is the same as the voltage across the other breakers. This will tell you whether or not your replacement circuit breaker can pass the proper voltage through it.

Step 6; Close up

Replace the cover plate on the breaker box and turn off the main electricity once more. It is safer to complete this task with the power turned off to avoid the possibility of a screwdriver slipping and touching a live wire.

Once the cover plate has been reinstalled, turn on the main breaker and check that all circuit breakers are operational, including the newly replaced one.

Reasons a wire gauge is essential

Reasons a wire gauge is essential

While circuit breakers and fuses provide adequate protection against overloading and overheating wires, they do not offer complete protection. These devices are intended to detect current overloads and trip or “blow” even before wires reach a dangerous temperature. However, they are not infallible, and it is still vital to avoid overloading a circuit by plugging in too many appliances simultaneously.

When a gadget or appliance attempts to take more power from a circuit than the wire gauge is rated for, there is the possibility of a dangerous situation. For example, connecting a 20-amp heater to a 15-amp circuit constructed with 14-gauge wire is extremely dangerous. Suppose the circuit breaker fails to operate correctly. In that case, the heater will take more current than the wires can safely manage, and the cables may become hot enough to melt the insulation around the cables and ignite the materials around them.

Plugging in appliances with low electrical demands into circuits with more vital gauge wires and a more excellent amperage rating, on the other hand, poses no threat at all. The circuit will only draw the amount of power required by the plugged device and nothing more. For example, using a laptop computer with a low amperage demand on a 20-amp circuit fitted with 12-gauge wire.

The usage of light household extended cables poses the most significant risk because of the possibility of shock. Many house fires have happened due to using a light extension cord with a 16-gauge cable to power a heater or other heating appliance of some kind.

When it comes to portable heaters, most manufacturers advise against using extension cords. However, if one must be used, it must be a heavy-duty cord with a high amp rating that matches the amps of both the appliance and the circuit into which it is plugged.

Sizing of wires

If you’ve ever gone shopping for electrical wire, you’ve probably realized that there are many different sizes and types of electrical wire to pick from. Different kinds of wire are intended for different applications, but when it comes to any of these wire types, knowing the proper wire size or gauge is critical to choosing the best option.

The American Wire Gauge (AWG) system is used to measure the size of wire. To refer to the physical length of the wire, it is rated with a numerical identification that runs in the opposite direction to that of the conductors’ diameter—in other phrases, the smaller the wire gauge numbers, the greater the diameter of the conductors’ diameter.

The amount of current that may safely run through a wire is determined by the diameter of the wire. Each gauge has a safe limit carrying capacity, measured in amperes of electrical current.


The National Electric Code (NEC) is a set of regulations that are in place to ensure that safe practices are followed when using electricity in the home. It would help if you did not make any changes to your home’s electrical system that violate any of these regulations, as they are in place to make the systems in the home safer.

A 20 Amp fuse will blow in a 30 Amp circuit before you even realize what you have done. It is risky to replace a 20-amp fuse with a 30-amp fuse because the 20-amp fuse may not blow quickly enough, causing damage to an electronic cord or causing a fire.

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