How Many Amp Breaker For Water Heater

What Size Breaker for a Hot Water Heater: A Breaker Size Solution

Is your electrical water heater tripping the breaker on a regular basis? Is it possible that your heater overheated without you noticing? You have clearly indicated that you are experiencing difficulties in matching your appliance with its safety device based on just a few questions. What size breaker do you recommend for a hot water heater, I hear you ask? For the most part, 30-amps is the common size for heaters. It is important to note that this breaker ampacity does not necessarily work for every water heater available.

Understanding Your Water Heater

When purchasing an electric water heater, one of the most common mistakes made by homeowners is failing to verify the amperage rating of the unit. Some heater tanks are just labeled with the voltage and wattage requirements, but not with the ampacity requirements. It is preferable if you obtain your tank specs from the shop or the brand manufacturer directly themselves. The size of your heater must serve as the foundation for establishing the appropriate breaker size. The following are the three criteria you should examine in order to assure your safety: Voltage-The volts provided by your boiler are critical to the operation of a properly functioning circuit.

Make a note of how much power your heater requires and include it in your list.

It will assist you in your quest for a proper breaker to manage the situation.

An mismatched size or broken cables that have been reused might put your heater and breaker at greater risk than they are worth.

A Breaker Size Solution: What’s the Formula?

If you’re unsure of the amp size you’ll need, doing a simple calculation will provide the answers you need. Knowing the wattage and voltage of your water heater already, all you have to do is follow the Ampere formula, which is I (amps) = P (watts)/V (voltage) (volts). As an example, I have a 3,000-watt heater tank that requires 120-volt power to operate. You must divide your watts by the number of volts in order to obtain its amperage. Solution: I = P/VI = 3000 watts / 120 volts is the formula.

  1. You could be thinking that a gadget with a current of 25 amps necessitates the use of a breaker with the same capacity.
  2. The National Electric Code (NEC) stipulates that you must maintain a continuous load of 125 percent of the maximum continuous load at all times.
  3. Applying the continuous load rule to the previous example, we get 31.25 amps: 125 percent x 25 amps = 31.25 amps.
  4. The Square D by Schneider Electric HOM235CP is a highly recommended device for a 35-amp circuit breaker.

Allowing enough room for your breaker will allow a power surge to occur without triggering the breaker. Check out this video from House Wiring T.V. to get a better understanding of how to properly size your water heater wires and breakers! – Video on YouTube

What Size Breaker for 40 and 80-Gallon Water Heater?

Calculating the amp size you’ll need is straightforward if you don’t know what you’re doing in advance. Knowing the wattage and voltage of your water heater already, all you have to do is follow the Ampere formula, which is I (amps) = P (watts)/ V (voltage) (volts). Take, for example, my heating tank, which requires 120-volt power and consumes 3,000 watts of electricity. Using watts divided by volts, you can calculate the amperage. Solution: In this equation, I=P/VI=3000 watts / 120 volts. Amperage = 25 volts Your first thought may have been, “A gadget that draws 25 amps needs a breaker with the same size.” This is correct.

  1. The National Electric Code (NEC) stipulates that you must maintain a continuous load of 125 percent of the maximum continuous load at all time.
  2. Applying the continuous load rule to the previous example, we get 31.25 amps: 125 percent x 25 amps.
  3. It is highly recommended that you use the Square D by Schneider Electric HOM235CP 35-amp CB.
  4. If you give your breaker enough room, it will enable a power surge to pass through without triggering the breakers.
  5. to get a better understanding of how to size your water heater wires and breakers correctly!

What’s the Correct Wire Size for a Water Heater?

If the wiring between a water heater and its breaker is mismatched, the connection will not function properly. Check that the amperage of your heater corresponds to the size of the wires on it. You can use the following list as a guide:

  • 20-amp heaters require 12-gauge cable
  • 25-amp heaters require 10-gauge wire
  • 30/40-amp heaters require 8-gauge wire
  • And other big heaters up to 50-amps require 6-gauge wire.

Also, evaluate the size of your water heater’s circuit breaker. Circuit breakers rated at 30 amps, which are often used for big boiler tanks, require a 10-2 nonmetallic or MC cable. It is appropriate for starting loads up to 40 amps and a steady load up to 35 amps with this type of wire.

Preventive Measures Before Buying a Circuit Breaker

When selecting the appropriate water heater circuit breaker size, it is important to be mindful of the amp differential between the breaker and the water heater. It’s critical that you obtain the correct size. A breaker that is either too large or too little might result in an electrical hazard. If your circuit breaker is too tiny for the amperage needs of your water heater, you should anticipate your CB to trip on a regular basis. Not only that, but too much switching on and off of the heater might result in internal damage to the device.

A breaker that is capable of handling a larger amperage than designed does not always imply that it is safer for the heater. If the tank experiences a sudden short circuit or overload, your circuit breaker will ignore the occurrence, providing no protection at all.


Choosing the appropriate size circuit breaker for a hot water heater is not that difficult if you obtain the necessary information. You can determine the right breaker size simply by studying the three wire heater factors — voltage, wattage, and wire size — and how they interact. A basic calculation would also suffice, but keep the breaker size as close as possible to the quantity of your response (the actual amp size of the heater). A 30-amp circuit breaker is commonly used for an electrical water heater, thus a circuit breaker such as the Q230 30-Amp Double Pole Type QP Circuit Breaker will be suitable for the job.

What Size Breaker Do I Need for a 4500 Watt Water Heater?

In response to the often asked question, “What size circuit breaker do I need for a 4500 watt water heater?” you’ll need either a 25-amp or a 30-amp circuit breaker, depending on your needs. For continuous loads, this solution complies with the 125 percent guideline established by the National Electric Code for circuit breakers, which states that the breaker should not be used for more than 80 percent of its rated current. Are you interested in learning how we arrived at this conclusion? Continue reading to see how you may calculate it, as well.

How to Calculate the Correct 4500-Watt Water Heater Breaker Size

The size of the circuit breaker has traditionally been determined by dividing the total wattage by the voltage. In order to determine the appropriate size circuit breaker for a 4500-watt water heater, we must divide 4,500 by 240. In this case, the answer is the precise value that you receive when you convert 4500 watts to amperage: 18.75. Because a water heater is a continuous load device, we must increase that figure by 125 percent in order to account for the additional load. The resulting current is 23.4 amps.

If the water heater was not classified as a “continuous load,” it would have been acceptable to use the full capacity of the circuit breaker.

If you have the opportunity, please take the time to view this video, which covers a variety of different calculations related to selecting the appropriate circuit breaker size for every type of application: Recall that it’s critical to determine if your item is a continuous load or not, especially if you don’t want your circuit breaker to trip on a regular basis.

Don’t Forget About the Right Wire Size, Too!

After all, the proper breaker and wiring size are always used in conjunction with one another.

The proper wire size for a 4500-watt water heater is a 10/2 wire or a 10-gauge non-metallic wire in this case. It is our goal that this information regarding what size breaker do I need for a 4500 watt water heaterconfirms what you already know about electrical safety and circuit breakers.


To summarize, you may utilize a 25-amp or 30-amp breaker for a 4,500-watt heater, depending on your needs. In terms of wiring, you may use either a 10-gauge wire or a 10-2/0 wire for this configuration. We hope that now that you are aware of the proper breaker size and wire gauge for a 4500-watt electric hot water heater, you will continue to educate yourself on how to properly handle your own electrical systems. Even a sliver of knowledge may make all the difference in ensuring that you do the task correctly and securely.

What Size Breaker Does a Water Heater Need?

Circuit breakers are required for the operation of your electric water heater and gas tankless water heater. Choosing the incorrect size circuit breaker, on the other hand, might result in poor safety and even damage to the water heater. Because of the increased electrical flow via the breaker, the wires are at risk of overheating, resulting in a fire and inflicting damage to your water heater. Circuit breakers and wiring for electrical safety are specified in the National Electrical Code, which defines rules for their sizing and installation.

  1. For safety reasons, it is suggested that you purchase a circuit breaker with more capacity than the electrical load of your electric devices – in this example, your water heater – to ensure that you are not electrocuted.
  2. This indicates that the breaker only provides power to the water heater and does not provide power to other appliances.
  3. On occasion, I’ll come upon a 4500-watt water heater that has a 20-amp circuitbreaker.
  4. The size of the breaker is decided by the wattage of the heating components, not the size of the storage tank.
  5. 240-volt circuit breakers are required for a water heater that has a 4500-watt heating element.
  6. With a smaller 12/2 cable and a 20 amp circuit breaker, the 3800-watt heating element may be connected to the rest of the system.

Sizing Water Heater Breakers

Understanding how a water heater works is essential to determining the appropriate size for the heater to be installed. Electric water heaters operate on alternating current, which ranges from 220 to 250 volts in voltage. You’ll need a double circuit breaker that’s rated appropriately for the amount of electricity the water heater is drawing.

For most electric water heaters, we’re looking at a current of between 20 and 30 amps. When determining the appropriate size based on the power needs, it is also necessary to consider the wire gauge size. The wire gauge size is determined by the amount of current drawn by the heater.

Element Watts Breaker Size 120v Breaker Size 220v Wire Gauge
1500 15 amp 15 amp 14
2000 20 amp 15 amp 14
2500 30 amp 15 amp 14
3000 30 amp 15 amp 12
3500 NA 20 amp 12
4000 NA 25 amp 10
4500 NA 30 amp 10
5000 NA 30 amp 10
5500 NA 40 amp 8

How Do You Calculate Breaker Sizing?

The power and voltage ratings of your water heater should be checked. The wattage and voltage rating of a water heater are labeled on a sticker that is attached to the thermostat panel. This information may be found around the base of certain heaters. While the majority of household water heaters have a capacity of 4500 watts or less, commercial water heaters can exceed 5500 watts or more. Let’s get down to the nitty gritty of determining the breaker sizes. 4500 divided by 240 equals 18.75 amps.

  • If you have a 4500-watt water heater that runs on 240 volts, you should be able to get 18.75 amperes out of it using the conventional division formula.
  • As a result, multiply 18.75 by 125 percent to account for the fact that a water heater operates on a continuous load.
  • When we round that value down to the next tenth, we obtain 25 amp.
  • It is commonly utilized because the minimum rating of 220 volts is greater than the 25 amp rating of the 25 amp breaker.
  • 20.45 amps multiplied by 125 percent equals 25.568 amps, which is rounded to 30 amps.
  • After all, it’s closer to 18.75 than 18.75.
  • However, according to the National Electrical Code’s 125 percent guideline, a 20 amp circuit poses a danger of frequent tripping and might cause damage to the water heater.

What Size Circuit Breaker for Gas Tankless Water Heaters?

Compared to electric tank water heaters, gas tankless water heaters consume less electricity and produce less voltage. Typically, it’s around 12 amps and less than 120 volts in voltage. In order to power the electronic ignition system on gas tankless water heaters, a little quantity of electricity is required. A gas tankless water heater only requires a dedicated single-pole breaker with a 15-amp, 120-volt rating for this reason.

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Should I Have Electric Water Heater or Gas Water Heater?

This decision is based on your geographic location as well as the utility costs in your region. Gas water heaters, on the other hand, are often more expensive to purchase up front but less expensive to operate than electric water heaters. In contrast to gas water heaters, electric water heaters are more energy efficient than their gas counterparts. The cost of gas is 40 percent more than the cost of electricity. As a result, it would be more cost effective to utilize gas. Electric water heaters, on the other hand, are more cost-effective when considering the time saved over time.

If you want to make changes to your home in order to accommodate electric, gas, or tankless water heating systems, you should consult with a specialist.

Before beginning any job, you should contact with a competent expert and verify that all necessary permits have been obtained.

As an affiliate, participates in a variety of affiliate programs with other websites. Hubert Miles receives a commission for recommending visitors and commerce to these businesses.

What size breaker do I need for a water heater?

Asked in the following category: General The most recent update was made on the 25th of January, 2020. When using an electric water heater, you’ll need to install a 240-volt dedicated circuit that will only service the water heater and no other appliances or gadgets. In most cases, the circuit wiring will consist of a 30-amp double-polebreaker and 10-2 non-metallic (NM) or multi-conductor (MC) cable. The wiring requirements for 3800 watt elements are less strict than the wiring requirements for 4500 watt components.

  1. The 3800 may be connected with a 12/2 wire and a 20 amp breaker, among other things.
  2. It is common practice to use 10 conductors with ground (10/2), as well as a 30 amp circuitbreaker for water heater circuits.
  3. A water heater of this sort must be considered a continuous load, which means that the branch circuit must be estimated at 125 percent of the water heater’s rated ampacity in order to be considered safe.
  4. Approximately how many amps does a 50-gallon water heater consume?
  5. The current drawn by a 4500 volt circuit is 18.75 amps, therefore it will not trip a 20 amp breakers, but it will operate the breakers at over 95% of their 20 amp capacity rating, and most breakers are not rated for that level of operation.

(A Must Read) Water Heater Breaker Size & Water Heater AMPS

Water Heater Breaker Size (A Must Read) | Home»Blog»(A Must Read) Water Heater Breaker Size 2562 views for AMPS2562 water heater The circuit breaker is an essential piece of equipment for any business, as well as a critical security measure for your property. If the electrical lines in a building cause the electric current to overflow, these basic devices minimize the energy consumption until the problem is resolved by a qualified repair specialist. As a result, it is critical to select the appropriate breaker size and how many amps are required for the water heaterbreaker.

The circuit’s velocities pass via a mechanism that serves as a resistor on a constant basis.

Circuit Breakers: Determining What Size Breaker for a Water Heater

Within the branch circuit, the current cable is connected to both sides of the switch by means of a binding cable. If the button is switched to the “on” position, the energy can travel via the tiniest terminal. It transmits the electromagnet, makes a secure connection with a specific terminal, and then proceeds to the upper terminal. Electromagnetic energy attracts and magnetizes electrical energy.

The magnetic pressure of the electromagnet grows as the strength of the electromagnet increases, and the current decreases the magnetism. Additionally, in conjunction with the improved motions to light levels, the magnetic is powerful enough to yank on the transmission connection with a metal lever.

How to Size Breaker for a Water Heater

Here’s a step-by-step guide to assist you determine what size circuit breaker you’ll need for your electric tankless water heater:

  1. Find a list of the criteria for the water heater and follow it.

In most cases, the heating accommodation and the location where the cable escapes are related. Pay close attention to the strong pull of the watts that power the water heater system. When it comes to household spinning heaters, 1,500 watts is the optimum amount. When it comes to the tag, you may basically employ its current-voltage to accomplish a state-of-the-art pull. It is recommended that the heater be connected to a normal ceiling socket and that the voltage required be 100 20 volts. If this is not the case, the maximum current reach for 1500-watt heaters is twelve and five amps.

  1. As a result, a 1500-watt heater on a 120-volt system necessitates the use of a 15-amp breaker.
  2. What size breaker did you choose for a water heater, and how did you come up with it?
  3. In order for your heater to operate as efficiently as four continuous 60-watt light bulbs on the equivalent circuit, two amplifiers must be included to the current drawing equation.
  4. It is not as simple as that to change the circuit breaker.
  5. When the situation is reversed, on the other hand, the option is less complicated.
  6. It is necessary to make modifications to the circuit breaker as well as the outlet receiver.
  7. If you attempt to use a 30-amp appliance on a 20-amp cable, the wire may become hot and may ignite, posing a fire hazard.

How Many Amp Breaker for Water Heater?

Examples of typical circuit breakers are shown below. A 15-amp controller with a 110-volt supply is an example of a water heater’s breaker circuit. Some models have a 220-volt plug with a 20-amp rating. The amperage on the button is indicated by the number 20 once more. These are only examples of situations in which the number of amp breakers required for your water heater may differ. If you are still not persuaded, you should consult an electrician before making a purchase.

How Many Amp Breaker Will It Take for The Current to Trip?

If this occurs, it is due to an overload of the system; alternatively, it is due to the fact that these high current appliances consume more current (scope) than the wiring in your house is intended to safely manage. The cause for the interference in your circuit is due to the fact that fuses are constantly blowing (fuses standard in old homes). In this instance, such device types should be linked to a separate or associated circuit if they are to be accessed or utilized separately from other devices.

  • The fuse or disconnector should never be bypassed or replaced with a higher-ranking fuse or disconnector.
  • Room heaters are an excellent way to warm up certain areas of your home without having to raise the thermostat.
  • It is recommended to use the wall outlet with space heaters if your house is connected to certain circuits (for example, if there is just one wall outlet in a cabinet).
  • So, how many amps does a water heater require in terms of a breaker?
  • In addition, it is critical to understand that extension cables should never be utilized with space heaters.
  • Extension strings have the potential to overheat and constitute a fire hazard.
  • Heaters for the noisy 120-volt wall outlet should be directly connected into the area to avoid wasting energy.

In addition, the connector’s temperature is constantly being monitored. Ceiling pipes that have been washed or even new ceiling pipes that have been badly installed can overheat and cause the socket to feel very warm, or they can cause the cap to burst over time.

Tip: How Many Amp Breakers You Need to Finish It Correctly?

When using an integrated water heater, the wattage tag for the heating element is affixed to the top of the water heater. It should be apparent due to the fact that it is located adjacent to the heating element board and must be accessible at all times. It has to be right close to the board to be effective. The operational voltage as well as the unit watts are displayed on the tag. When using 240-volt electricity, your heater typically has two components, which means you’ll see two wattage standards—one for each component—on the display.

What Size of Breaker for Water Heater and How Many Amp Breaker a Water Heater Vital Information:

In an integrated water heater, the wattage tag for the heating element is affixed to the top of the heater. The fact that it is located adjacent to the heating element board and must be accessible at all times should draw attention to itself. In addition, it must be close to the board. The operational voltage as well as the unit watts are displayed on the label. It is common for your heater to be divided into two components, which means that while using 240-volt electricity, you will observe two wattage standards, one for each of the two components.


If the circuit breakers and electrical cables are not functioning properly, do not attempt to establish a fault magnitude. In the event that you use a substandard lock, you run the risk of breaking the oven and perhaps causing damage to your electrical system. Once again, understand the figures that go into the size of the breaker for your electric water heater and how many amps you’re going to require.

Different Types Of Water Heater Breaker Sizes – Which One To Select?

A circuit breaker is a device that prevents electric machines from being damaged by short circuits or overcurrents. In the absence of one, the unprotected machine may cease to function at any time. As a result, water heaters are nearly always required to have one of these. Several heaters, in fact, will not function at all unless they are first linked to an electrical circuit breaker. Circuit breakers, on the other hand, are available in a variety of sizes, just as water heaters are. Consequently, while you may always connect a water heater to a breaker, you must make certain that the connection is of appropriate size.

Choosing the appropriate size, on the other hand, is not straightforward.

Throughout this section, we’ll go over everything you need to know to ensure that choosing the appropriate size isn’t too difficult.

Check out the video below.

How Is a Water Heater Breaker Size Measured?

Amperes are the units of measurement for the size of a circuit breaker. Versions ranging from 25 Amp to 100 Amp are available, with the biggest models capable of reaching 100 Amp. Of course, the Amp measurement refers to the number of Amperes that the circuit is capable of handling. Circuit breakers are designed to shut down automatically when the Amp capacity of an electrical connection exceeds the capacity of the circuit breaker.

That is the standard by which they are evaluated. In fact, that is how they operate. As a result, you should always seek for the appropriate Amp capacity based on the requirements of your heater.

How to Size Breaker for a Water Heater?

Now that you have a better understanding of how breakers are assessed, it is time to learn how to select the most appropriate one for your requirements. To get started, here are some suggestions:

1. Find the Requirements of the Heater

The first step is to determine the overall wattage of the water heater as well as the type of connection that will be utilized. As a result, you’ll need to double-check the specs label behind the water heater on a regular basis. It will tell you how much power it requires in total watts as well as the sort of connection it requires. For example, most household water heaters consume around 1,500 watts of continuous power when connected to 120-volt operating voltage.

2. Divide Current by Voltage

If your water heater requires a total of 1,500 watts to operate and operates on 120-volt connections, you’ll need to split the entire amount of power required by the water heater and the 120-volt connections. That’s 1,500 watts at 120 volts, to be precise. This will provide you with the entire amperage. In this situation, 12.5 Amp is the amount of current required to get the water heater to function.

3. Find out the Right Operative Amperage

Once you’ve determined the amperage required to get your water heater up and running, you can move on to determining what the optimal amperage would be. What is the significance of this? Most circuit breakers, on the other hand, perform consistently well only if they have a power capacity of 125 percent of the power capacity required by the water heater. That implies that a 1,500-watt water heater connected to a 120-volt line will not function properly when connected to a 12.5 Amp circuit breaker.

However, even in this case, it falls short.

As a result, only a 20 Amp breaker will be sufficient for a 1,500-watt heater operating on 120-volt connections.

4. Picking the Right Size

Now that you have a better understanding of the options available to you based on your water heater requirements, it is time to discuss what size you should purchase. It’s important to remember that there aren’t only 1,500 watt heaters available. That is why it is vital to be familiar with the many varieties you may encounter. In most cases, it is important to have a breaker that can handle 125 percent of the water heater’s Amp requirements. However, this will not ensure that the product continues to function properly over an extended period of time.

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What exactly does this imply?

Instead, a minimum of 25 Amp is required.

As a result, it will not perform as well as it should. In contrast, when using a 25-Amp circuit breaker, the 20-Amp water heater will only be able to provide 80 percent of the circuit breaker’s complete capacity. Thus, it will perform consistently and in a consistent manner.

5. Final Choice

Of course, matching up the appropriate circuit breaker with the water heater’s demands is beneficial in this situation. However, you will need to take into account any other electronic or mechanical devices in the vicinity. Aside from that, you’ll want to make certain that you’re purchasing the correct circuitry. It is not just about the volume of the container, but also about the level of protection you require. Circuit breakers are available in a wide range of styles with a variety of functions to choose from.

As an example, if you have a heater that consumes 6,000 watts in total and is connected to a 240-volt system, the operational ampere total would be 25 Amp.

Because it will take a total of 25 Amp, a 30 Amp breaker will be sufficient, but a 35 Amp unit will be sufficient if more than just a heater is required.

Which Size of Water Heater Breaker to Go For?

As you can see, this may be much more difficult than it appears. Circuit breaker selection for water heaters has never been a simple task, which is why it is always best to entrust this task to a qualified specialist. It’s probable that you’ll acquire the suitable circuit breaker if you follow the guidelines in this article and don’t neglect any of the small details. Don’t leave your water heater vulnerable to energy problems; instead, with our assistance, install a breaker to keep it safe. You will not be disappointed!

Here are a few of the most popular circuit breakers available on Amazon: The most recent update was on 2022-02-21 / The following are affiliate links and images sourced from the Amazon Product Advertising API.

It is possible that we will get a commission if you make a purchase after clicking on links in this story.

What Size Breaker for a 40 Gallon Electric Water Heater? [Calculated]

It is possible that we will receive commissions for purchases made through the links in this post. A circuit breaker is an essential piece of equipment for every circuit. When there is an overload, it safeguards the device by turning it off quickly. Because the water heater consumes a significant amount of power, it must be connected to the appropriate circuit breaker! The question is, what size circuit breaker do you require for a 40-gallon electric water heater? Generally speaking, a 30A double pole breaker would be required for a 40-gallon electric heater.

Make certain, however, that your water heater is connected to a 240-volt dedicated circuit before proceeding.

There should not be any other appliances connected to it at the same time. You might be wondering how to select the best breaker for your needs. Which brings us to our point of view! Continue reading to find out more information!

Factors that Determine the Right Breaker for A Electric Water Heater

Choosing the incorrect circuit breaker might result in significant incidents such as short circuits. Furthermore, selecting the proper circuit breaker is critical to the performance of your heater. As a result, when purchasing a circuit breaker, you must consider several factors. These elements are as follows:


The first thing you need to know about your heater’s voltage requirements is what it is. Depending on the size and wattage of the heater, the voltage might range between 220-240 volts. Your heater must be connected to a circuit based on the voltage it produces.


Wattage must be considered in the same way that voltage must be considered. Wattage varies depending on the capacity of your heater as well as other aspects such as its size, power, features, and so on. Consequently, be certain that you understand the wattage of your heater.

Type of Wire

You must also know what type of wiring are compatible with your heater before you proceed any further. When choosing a heater, it’s important to consider the wattage. Making the mistake of using an unsuitable or defective wire might do more harm than good. Once you’ve taken note of all of these considerations, you may proceed to the following stage.

What Size Breaker for a 40-Gallon Electric Water Heater Should I Get?

The process of determining the size of your circuit breaker has become rather straightforward in recent years. You only need to perform simple calculations in order to find the appropriate size circuit breaker for your needs. We must first establish the amperage in order to determine the appropriate size of the breaker. After dividing the wattage by the voltage, you may compute the resistance. Calculate 125 percent of the amperage to get at a safe quantity for the size of the breaker following that calculation.

  • In addition, make certain that the heater’s cables are of the proper size.
  • 4500 watts is the wattage.
  • parage= 1500/240= 18.75 kilowatt-hours Taking into consideration the constant load we get, 18.75 x 125 percent = 23.4AT When using a 40-gallon breaker, a 25- or 30-amp circuit breaker is adequate.
  • When it comes to water heater breakers, here are some of our top picks for you to consider: These are some of the top products available on the market.

Precautions before Determining The Size of Breaker:

When it comes to finding the proper breaker for your water heater, you must exercise extreme caution. If the circuit breaker is either too large or too little, it will only cause additional problems in the long run.

In Case of Less Amperage

If your circuit breaker has less amperage than is necessary, it will trip repeatedly until it is replaced.

This will cause your heating to be turned off unexpectedly. Additionally, it has the potential to harm the internal settings of your heater. Therefore, you should take the wattage of your switches into mind. You can’t always use a 15 amp switch on a 20 amp circuit because the circuit is too large.

In Case of High Amperage

It might potentially be extremely dangerous if the amperage is higher than is necessary. Even in the event of an overload, it will not reply. This might do serious harm to your heater and any other appliances that are connected to it. The size of the circuit breaker you require for your 40-gallon electric heater has finally been determined. Now is the time to choose the best one for you!


Should I get a 4500-watt heater or a 5500-watt heater? Answer:It is totally dependent on your requirements. A 4500-watt heater, on the other hand, is preferable since it consumes less power. As a result, if you have similar heaters with differing wattages, we recommend that you get the 4500-watt heater. Question: How far away from the breaker box does the heater have to be in order to function properly? Answer: There should be a space between the panel and the wall with a depth of 36″. Make certain that the front of your heater is at least 36″ away from your panel of electrical outlets.

When it comes to electric hot water heaters, a neutral is not required.

Final Words

When it comes to most electric appliances, a breaker is a lifesaver. It has the potential to rescue your appliances from harm and to save them from suffering irreversible losses. However, the type of breaker you select has a significant impact on the outcome. In this post, we’ve covered all you need to know about the size of breaker you’ll need for a 40-gallon electric water heater. We hope you find this information useful! My name is Scott, and I’m from the town of Fort Mohave in the state of Arizona.

In addition, I am the delighted father of two sons, George and Andrew.

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Are you concerned about blowing a fuse in your water heater or causing a fire in your home because you did not utilize the proper circuit breaker? I understand how you’re feeling. I also considered what size circuit breaker I would use for a water heater. Choosing the incorrect circuit breaker might have catastrophic ramifications. I will assist you in determining the appropriate size of circuit breaker to utilize for your water heater, as a result of which

How Does a Conventional Water Heater Work?

Before I lead you through the process of choosing the appropriate size of circuit breaker to utilize in your water heater, let’s go over the fundamentals first. Two thermostats and two heating elements are often found in the top and lower parts of an electric water heater’s tank, which is divided into two pieces. Once the tank is completely filled with water, the upper thermostat activates its heating element, which raises the temperature of the water in the upper half of the tank. Heat rises from the bottom, triggering the lower thermostat and igniting the heating element in the lower thermostat.

The lower thermostat, on the other hand, continues to manage the lower heating element until the water heater reaches the temperature that is wanted.

After then, it turns off. The lower thermostat is set to switch on and activate the lower heating element for about 1 to 4 minutes per hour, 24 hours a day, seven days a week. It accomplishes this in order to keep the water at its optimal temperature.

How Does Electricity Heat the Water?

According to what we discussed before, your water heater need power to activate the heating elements in order to function. A conducting wire is pushed through by the voltage of your home’s electrical system, which is measured in amperes. All cables have resistance, which reduces the amount of electricity that flows through them. In addition, it generates heat. When the electrons reach the heating element of the water heater, the voltage causes the electrons to be pushed through a resistance wire within the heating element by the current.

In addition, when the resistance wire heats, the water in your tank warms as well.

What is a Circuit Breaker and Why Do You Need It?

Remember how we discussed how the voltage pushed the electrons across the wire, causing heat to be generated? If there is an excessive amount of heat applied to the wires, the wire covering may melt, resulting in a fire. There must be a system in place to prevent the flow of energy from the power source to the water heater from continuing. The electrical supply from the source to the heating elements is interrupted when there is an excessive amount of power going through the circuit, which causes the circuit breaker to ‘trip.’ For better or worse, it disconnects the water heater from the power supply, preserving the integrity of the appliance as well as your home.

What is the Correct Circuit Breaker Size?

Circuit breakers are rated by their manufacturers based on the maximum amount of electric current (measured in amperes) that they can handle without tripping or breaking the circuit. When sizing an overcurrent safety device, such as a circuit breaker, electricians are required to follow the 80 percent rule, which is outlined in the National Electrical Code (NEC). It is required by code that a circuit breaker should not be able to handle more than 80% of the electrical rating on it. Using the 80 percent rule, you can reduce the amount of heat created in an electrical circuit while running it at full capacity for at least three hours.

For devices that don’t require a constant electrical demand, circuit breakers with 100 percent of their rated capacity can be used to accommodate them.

What Size of Wiring Do I Need for My Water Heater?

In order to determine the maximum electric current (in amperes) that a circuit breaker can handle without tripping or breaking the circuit, manufacturers rank their products. If an overcurrent protection device, such as a circuit breaker, is to be properly dimensioned, according to the National Electrical Code (NEC), electricians must adhere to the 80 percent rule. Circuit breakers are not permitted to handle more than 80% of their electrical rating, according to the law. For electrical circuits with a constant load for at least three hours, the 80 percent rule reduces the amount of heat created in the circuit.

For devices that don’t require a constant electrical demand, circuit breakers with 100 percent of their rated capacity can accept the gadget in question. It would be prudent to size your circuit breaker at 125 percent of its maximum rating due to the fact that water heaters are continually in use.

How to Determine the Correct Breaker Size for Your Water Heater

In this section, we will discuss how to identify the proper circuit breaker size for your water heater. Here are three simple steps to follow. 1. Determine the power and voltage ratings of your water heater. In most cases, the information may be found on a label sticker that can be found at the water heater’s power cable base or the thermostat control panel. If you are unable to locate this information, you may choose to consult the owner’s handbook or conduct an online model search. The majority of water heaters are equipped with a 4500-watt element that operates on a 240-volt system.

  1. 2.
  2. Consider the following scenario: you have a 4,500-watt water heater running on 240 volts.
  3. 3.
  4. We shall multiply 18.75 amperes by 1.25 to get 23.4375 amperes as a result of this calculation.
  5. Given that the water heater only uses 18.75 amperes at 240 volts and 4500 watts, you would conclude that a 20-amp circuit breaker is sufficient for the job.
  6. Remember the 80 percent guideline from the National Electric Code?
  7. In order to determine how much heat the electrical wires generate within the cables, there is no method to measure it.
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What Size of Circuit Breaker Should You Use for a 5500-watt Water Heater?

A 5500-watt, 240-volt water heater requires 22.9 amperes in order to function properly. Taking the result and multiplying it by 1.25 gives you a final ampere rating of 28.645. As a result, a 30-amp circuit breaker should be enough for this installation.

What Size of Circuit Breaker is Ideal for a 50-gallon Water Heater?

The heating components in most 50-gallon water heaters have a capacity of 4500 watts. 4500 watts divided by 240 volts is 18.75 amperes, which is a reasonable estimate. When you multiply 18.75 amperes by 1.25, you get a value of 23.4375 amperes. A circuit breaker with a capacity of 25 or 30 amps is recommended.


You should constantly remember the following methods in case you ever find yourself wondering what size breakers I need for a water heater.

  • Make a note of your water heater’s voltage and wattage specifications
  • The amperage rating of the water heater is calculated by dividing the power by the voltage. To get the appropriate circuit breaker size, multiply the amperage rating of the water heater by 1.25.

Isn’t that straightforward?

You may use this simple method to figure out the size of the circuit breaker required for practically any electrical item in your home or office.

What Size Breaker for a Hot Water Heater? – SaveourH2O

What kind of electric water heater do you have at home? For example, you might want to find out what size breaker you should use for a hot water heater before purchasing one. In order for your water heater to function properly, you must have a circuit breaker installed. The majority of electric heaters require a 240-volt dedicated circuit; this circuit requires a 30-amp two-pole breaker and a 10-2 nonmetallic cable or metal-clad cable, among other components. The size of your water heater’s circuit breaker should be proportional to the electrical requirements of the heater.

How Does A Circuit Breaker Work?

An electric breaker, also known as a circuit breaker, is responsible for ensuring that electrical connections remain in the safe mode, particularly in the case of a short circuit or an overcurrent incident. It pauses the current flow in order to prevent circuit damage, which can result in fires and the failure of the entire electrical system. It serves as a safety measure, protecting you from receiving an electric shock or having your water heater’s performance disrupted.

How To Find The Proper Breaker Size For Water Heater?

When determining the exact breaker size you want for your water heater, it is critical to consider the capabilities of the circuit that will be serving the water heater. When designing a circuit, you should ask yourself, “What is the greatest amount of electric current that I wish to pass through the circuit?” According to the National Electrical Code, the size of the circuit breaker shall not be less than 125 percent or more than 125 percent. We must follow these four simple procedures in order to determine the suitable breaker size.

  • Identifying the existing rating of your water heater should be the first step in the process of upgrading your system.
  • Residential water heaters are typically rated at 1500 watts of energy consumption or less.
  • If a water heater has two heating elements, you will see two different wattage figures – but they will not be operating at the same time.
  • It is not necessary to add the two wattages together.
  • Figure out what the maximum current capacity of your water heater is.

Decide on your water heater’s maximum current consumption; Why is it critical to ensure that the right operating amperage is used? This is due to the fact that the breaker size may not be compatible with the operating voltage of your heater in some instances. When using a 1500-watt heater on a 120-volt circuit, the circuit should have at least 15.6 amps of current.

A 15 amp breaker, on the other hand, could be a little inadequate for this design. As a result, a more powerful circuit breaker would be required. A 20-amp circuit breaker would most likely be the most appropriate choice.

  • Find out what your load breaker’s current rating is for both continuous and noncontinuous loads.

This step will provide you with the information you need to determine what breaker size you should purchase. Multiply the existing rating’s value by 125 percent to get the new rating. Homeowners frequently believe that the maximum amp of their water heater corresponds to the same amount of breaker amperage. This is not always the case. Because each circuit breaker can only utilize 80 percent of the total amperage available, it is generally recommended to purchase circuit breakers with a greater amperage rating.

  1. Circuit breakers and Overcurrent Protection Devices are typically built to handle 100 percent of the rated current in most cases.
  2. Nevertheless, for continuous loads, the 125 percent suggestion is recommended in order to achieve a safe current limitation.
  3. It is critical to know the load capacity of a circuit breaker.
  4. Determine the size of a 30A non-continuous load water heater’s circuit breaker using the following example: When dealing with a 30A non-continuous load, you can utilize a 30 amp circuit breaker.
  5. Accordingly, 30A non-continuous load equals 30A circuit breaker.
  6. Example 2: Calculate the size of a circuit breaker for a 28A continuous load water heater using the formula below.
  7. 35 AH is equal to 1.25 x 28 A.

Points To Remember When Choosing A Circuit Breaker Size

  • The 125 percent figure is only applicable to continuous loads, not intermittent loads. It is compatible with the vast majority of water heaters that operate on 240-volt circuits. If you’re just intending to use your water heater periodically (i.e., not on a continuous basis), a circuit breaker with a 100 percent rating would suffice. A 30 amp breaker necessitates the use of a 10 gauge wire. Both devices are suitable for use with 240V heaters. It is important to remember that if you have other devices connected to the same circuit as your water heater, you must include their amperage in the overall current demand. It is possible to lose the safety function of your breaker if you lower the size of the breaker without updating the entire wiring and circuitry. When there is poor wiring, a circuit breaker will trip and break quickly. It is possible that a broken thermostat can cause your breaker to use more power, which will eventually cause it to trip. Unless the load current is very high, breakers cannot be much greater than the ampacity of the wire. It is recommended that you utilize a circuit breaker with a capacity double the amperage of your water heater. Always double-check that the circuit breaker you’re installing is compatible with your current panel.


It might be difficult to determine the correct breaker measurement. It is usually a good idea to consult the specification sheet of your hot water heater when putting together information regarding what size breaker to use with your hot water heater. You will use it as a starting point for your circuit breaker sizing calculations. By following the methods outlined above, you will be able to determine which kind will function most correctly with your water heater. There should be no assumption about the effectiveness of this action plan, which assures that your water heater will not have any electrical problems.

Water Heater Amps

Making sure that your water heater has the appropriate amperage avoids your home’s electrical system from getting overwhelmed. Get quotations from as many as three professionals! Enter your zip code below to get matched with top-rated professionals in your area. Because there are so many various types of water heaters on the market, it can be difficult to determine how many amps your water heater requires. Your home’s electrical system might soon become overwhelmed if you don’t have enough amperage available.

If you’re thinking about upgrading your water heater, there are a few things to consider when determining how many amps your new water heater will require.

What is the Standard Amperage for an Electric Water Heater?

The majority of electric water heaters operate at 240 volts and 18.8 amps, with a heating element rated at 4,500 watts. A gas water heater consumes less amps than an electric water heater—about 12 amps at 115 volts. The typical home container heater has a 40-gallon tank and is powered by a 30-amp circuit breaker, according to the manufacturer. The actual amount of amperage consumed by water heaters varies across models and is dependent on important factors such as the kind of water heater being used, the type of fuel required, and the capacity of the water heater.

Water Heater Types: Tank vs Tankless

Goffkein may be found at Water heaters are classified into two categories: tank and tankless. The most common type of tank water heater, also known as a storage or container heater, has tanks that physically retain water and heat it on a continuous basis. Coils are built into tankless water heaters, and they heat the water on demand while you’re using it. While tankless water heaters often consume more energy and draw more current than their tank counterparts, they consume less power throughout their lifespan since they only operate when water is required.

Due to the fact that this breaker size is relatively common, it is unlikely that you will need to improve your electrical system in order to manage the required amount of electricity when installing a tank of this size.

If your property is older, you will almost certainly require the services of a professional electrician to improve your system and increase the amount of amperage accessible in your home.

Fuel Type: Electric vs Gas Water Heaters

  • An electric water heater (with a tank) necessitates the installation of a 240-volt circuit with a 30-amp circuit breaker. a 120-amp circuit breaker is required for a tankless electric water heater
  • A gas water heater with a tank requires 30 amps, but a tankless gas water heater necessitates the use of a 120-amp circuit breaker.

Water heaters can be powered by electricity or natural gas, depending on the model. Electric water heaters are often less expensive than gas water heaters, however the expense of maintaining an electric water heater is higher. For a new electric water heater, whether it is a tank or a tankless one, you will almost certainly need to modify your electrical system. Gas water heaters are directly connected to a gas line, which means that they are often more expensive to install at the outset of the project.

Other Factors That Influence Water Heater Amperage

Because the tank size varies, the overall quantity of power consumed by your water heater is determined by its capacity. Larger tanks will necessitate the use of more power in order to heat all of the water contained inside them. In order to accommodate a single person or a small family (no more than three people), a small 50- to 60-gallon storage tank is sufficient, while a larger 80-gallon tank may accommodate three to four people. In general, you should increase the size of your tank by 10 gallons for every additional person that lives in your home.

The higher the flow rate, the greater the amount of power required by your system. For example, if you want to run the dishwasher while also doing a load of laundry and taking a hot shower at the same time, you will most likely need to improve your electrical system to accommodate your demands.

Energy Efficiency

The energy efficiency of certain units is higher than that of others. The energy efficiency of electric water heaters is generally superior to the energy efficiency of natural gas water heaters. In most cases, tankless water heaters are more energy efficient than traditional tank-type water heaters. Additionally, energy-efficient machines that do not operate continuously, as well as newer ones, will consume fewer amps. The energy efficiency of your water heater is likely to be lower than that of newer models if it’s more than a decade old.

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