Not every water heater and breaker will line up perfectly. Plenty of water heaters are too big to run on certain breakers. In these instances, knowing what size breaker to use helps prevent common problems. If you’re wondering what size breaker is best for your water heater, we have created a list of recommendations to help you avoid electrical issues. This guide will outline the relationship between breakers and water heaters and provide the information you need to make a decision about the right breaker size.
Water Heater Amp Draw
The first thing to consider when determining what size circuit breaker is necessary for your system is the amp draw of the water heater. This will fluctuate from water heater to water heater. In most cases, larger water heaters will have larger amp draws, while smaller systems will have smaller amp draws.
Most water heaters have an amp draw that falls between eight amps and 40 amps or more. The exact amp draw of your water heater should be stated when you buy it or during the water heater installation process. If you didn’t buy your water heater, you might be able to determine the amp draw by consulting a product manual or by researching the exact model on the manufacturer website for the water heater.
If all else fails, you should be able to determine the draw by having a professional HVAC technician inspect the issue for you. No matter how you discover this information, having it is critical. Knowing exactly where your water heater falls on the amp draw spectrum is necessary to determine what size breaker it requires.
Water NEC 80% Rule
The other factor necessary for determining what size circuit breaker is needed for a hot water heater is the NEC 80% rule. The National Electrical Code (NEC) rule states that a breaker can only be loaded up to 80% of its maximum amperage. For example, a 30 amp breaker could handle a 20 amp water heater but not a 26 amp water heater.
Water Heater Breaker Sizes
In the United States, most water heaters run at 18.8 amps. Meanwhile, most breakers run at either 15A, 20A, or 30A. Since 80% of 20A is 16A, this means that the only breaker capable of handling most water heaters is a 30 amp breaker.
However, other options do exist. Smaller water heaters, like 10-gallon water heaters and 20-gallon water heaters, may be able to run on a 20 amp breaker. It’s still important to check the amps these heaters require, but alternatives are an option.
Meanwhile, larger water heaters have more significant requirements. Water heaters around 90 or 100 gallons can often still run on 30 amp breakers but may need more. Running the water heater on two 30-amp breakers may be necessary in these cases. Double-checking the amp requirements of a water heater is pertinent when dealing with water heaters of this size.
Understanding Your Water Heater
Fully understanding your water heater means more than just knowing about the amperage. Voltage, wattage, and wire size also play a part. Voltage determines what type of outlet the water heater can be plugged into. Most water heaters will work with a 220 or 240 volts outlet. However, this will vary depending on the size of the water heater.
Wattage is an important measure of the electrical requirements of a water heater. It is also a great way to determine how quickly a water heater will heat up, as water heaters with higher wattages tend to heat up faster.
Wire size also impacts water heater compatibility. The higher the amp requirement of the water heater, the thicker the wire it will need. Failing to conform to this rule can create a fire hazard or leave you in need of emergency plumbing services for your home.
What Size Breaker Is Necessary for a 40 and 80-Gallon Water Heater?
40-gallon water heaters are pretty average. Almost all of them will require a 30-amp breaker. Meanwhile, an 80-gallon water heater is significantly larger. Water heaters like this are on the larger end of the spectrum when it comes to water heater size.
Despite this, a 30-amp circuit breaker for a water heater will typically get the job done. However, since an 80-gallon water heater is so close to needing more, it’s important to double-check the amp requirements on the specific water heater to make sure they don’t exceed 24 amps (which is 80% of 30A).
Water Heater Repair and Installation Services
When dealing with water heater repair and installation projects, it’s important to do the job right. Tampering with the electronics of the system can pose a threat to a vital part of the infrastructure of your home. Our team of local plumbers in Stamford, CT offer comprehensive water heater installation services for homeowners in your local area.
Our technicians also offer other types of plumbing services including sump pump installation, water leak repair, drain cleaning, sink installation, and water line replacement. We understand what goes into every water heater job. We also offer same-day services with a money-back guarantee. If you need assistance with determining what size breaker you need for your new water heater, contact our team by phone at (860) 325-7836 to book an appointment.