Back to Blog

Close Up of Residential Breaker Box

What Size Breaker Do I Need for My Water Heater?

April 4, 2024

When it comes to ensuring the safety and efficiency of your home’s electrical system, knowing the correct size breaker for your water heater is crucial. Whether you’re installing a new water heater or checking if your current setup is up to code, understanding water heater amps and the appropriate water heater breaker size is essential. This guide will walk you through how to determine the right size breaker for your water heater, ensuring your system runs smoothly without tripping your electrical system.

Understanding Your Water Heater’s Electrical Requirements

The first step in determining the correct hot water heater circuit breaker size is to understand the electrical requirements of your water heater. Most residential water heaters are rated at 240 volts and can vary in power consumption, typically requiring a circuit breaker size that can handle the load without risking overheating or electrical fires.

Water Heater Amps

The power consumption of a water heater is measured in watts, but for circuit breaker sizing, we consider the amperage draw. To find out how many amps your water heater uses, you can look at the label on your water heater, which should list its wattage. The formula for calculating amps is wattage divided by voltage. Most residential water heaters range from 4500 to 5500 watts, operating on a 240-volt circuit. This translates to approximately 18.75 to 23 amps of current draw.

Calculating Breaker Size

Once you know the amperage draw of your water heater, you can determine the appropriate water heater breaker size. The National Electrical Code (NEC) specifies that the breaker size must be 125% of the continuous load. This means, for a water heater drawing 20 amps, you would need a breaker rated for 25 amps (20 amps * 1.25 = 25 amps). However, since breakers come in standard sizes, you would round up to the next available size, which is typically 30 amps for residential water heaters.

It’s important to note that the water heater breaker size may vary depending on the specific model and electrical requirements. For instance, a smaller water heater used in a one-bedroom apartment may require less amperage compared to a larger unit designed for a family home. Always refer to the manufacturer’s specifications and local building codes when selecting a breaker size.

Water Heater Breaker: Safety Precautions

Choosing the correct water heater breaker is not just about preventing your breaker from tripping. It’s also a critical safety measure. An undersized breaker can lead to overheating, risking damage to your water heater and posing a potential fire hazard. On the other hand, an oversized breaker may not trip when it should, failing to protect your water heater from electrical issues.

Frequently Asked Questions

Can I use a standard breaker for my water heater?

Yes, as long as it meets the amperage requirements and is 125% of the continuous load as specified by the NEC.

What if my water heater has a higher wattage?

For water heaters with higher wattage, you will need to calculate the amperage draw and select a breaker size accordingly, always adhering to the 125% rule.

Is it okay to DIY the breaker installation?

While some homeowners are comfortable with DIY electrical projects, installing or replacing a circuit breaker involves understanding electrical systems and ensuring adherence to safety codes. If you’re not confident, it’s best to hire a professional electrician.


Determining the correct size breaker for your water heater is essential for the safety, efficiency, and longevity of your electrical system. By understanding the amperage draw of your water heater and following the NEC’s guidelines, you can select the appropriate water heater breaker size. Remember, when in doubt, consult with a professional electrician to ensure your home is safe and compliant with electrical codes.

Ready to ensure your water heater is powered safely and efficiently? Contact our team at Lickety-Split today to check your system or for assistance with selecting the right size breaker for your water heater. Don’t wait until you’re left in the cold—ensure your water heater is properly protected now!


Home Services You Can Trust

When solving problems in your home, you want the people you trust most to be on the job.
Click to Call