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What Gauge Wire Do I Need for a 30-Amp Breaker? – Answered

Written by Edwin Jones / Fact checked by Andrew Wright

what gauge wire do I need for a 30 amp breaker

What gauge wire do I need for a 30-amp breaker? If this question enters your mind, you may want to install a new circuit or upgrade an old circuit. Well, to answer it directly, the minimum size required for a 30-amp circuit breaker is a 10-gauge wire.

However, when adding or installing a new circuit, the wire size is not the only thing you need to consider. It would help if you also determined the length of the wire and the appliances or devices you want to use in your circuit.

Reading this article will surely give you an idea of what you need to consider regarding your 30-amp circuit.

What is the Recommended Size Wire for 30 Amp Breaker?


The wire size needed for every electrical line depends on the current loads you need to run on it.

NEC Ampacity table

1. A 10-gauge wire

If you look into a 30 Amp wire size chart, the recommended size is a minimum of 10-gauge wire. A 10-gauge wire can safely carry the amount of current loads supplied by a 30-amp circuit.

2. A 8-gauge wire

Minimum size means that you can increase the size of your wire. If you need a more stable current supply of loads, you can use a thicker wire size.

There is no rule when it comes to using larger wire sizes. However, many professionals are recommended to use only 8-gauge wires as it is the maximum wire size for 30 Amp circuit.

If you look at the 30 Amp wire gauge chart, you will also see that a thicker wire has a lower number. AWG, or American Wire Gauge, established these standards for measuring electrical wires.

So, whenever you need a larger wire diameter for upgrading your lines, you may consider looking for a lower number of AWG.

This video by a Starving Electrician is also a good reference as he covers up all the necessary wires and circuit breakers for home electrical. It contains more than the combination of a 30-amp circuit breaker and 10-gauge wire.

Other Things You Need to Consider When Installing a 30 Amp Circuit Breaker

You must also consider the wire length for your 30-amp circuit, in addition to the wire AWG.

  • A maximum length of 150 feet is allowed when using a 10-gauge wire size.

It is worth using an 8-gauge wire size if it has exceeded the maximum length of 10-gauge wire to keep the current demand by your devices.

  • Another thing you should also consider is the 80 percent rule for the circuit breakers while looking at the device’s present loads.

You’re only permitted to use 80 percent of the circuit breaker’s capacity to avoid problems. Circuit overloads can occur when a load surpasses 80% of the breaker’s amp rating, especially for devices that require continuous loads.

What Happens if I Used the Wrong Length and Wire Size for 30 Amp Circuit?


Using less than the minimum size could result in severe property damage.

  • When overloads occur in the circuit, the circuit breaker may fail to detect the overloads, resulting in wire damage.
  • At the same time, the damaged wire may cause a fire, which could cause damage to your property.

However, using a thicker wire size will not affect your circuit. The circuit breaker can still detect overloads, short circuits, and other electrical issues in that circuit.

If you have plans to expand in the future, using a thicker wire is an advisable step.

The only drawback of using an 8-gauge wire for 30 Amp 220V is that it is more expensive than the recommended wire size:

  • The price may increase 20% from a regular price of 10-gauge wire. Its price also depends on the type of wire and the brand of the product.

On the other hand, as the wire length gets longer, the demand for electricity from your devices increases. It signifies that if you exceed the circuit breaker’s maximum length, the current it provides may be insufficient.

It is possible that your device doesn’t have enough loads this time, causing issues with the device.


Hopefully, now you know the answer to your concern, “what gauge wire do I need for a 30-amp breaker?”

Using the right 30 Amp wire size for your 30-amp circuit breaker is very important to prevent some unnecessary problems with your circuit.

 Furthermore, using a thicker wire is not prohibited, but it will cost you more. It is more suitable to use a thicker wire size if you plan on expansion.

Now that you know the recommended size for a 30-amp circuit breaker, we hope you carry on with your installation with confidence. Thank you for reading!

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