What size breaker do you need for a tankless water heater?

Asked By: Lixiong Pagazaurtundua | Last Updated: 26th April, 2020
Category: home and garden home appliances
3.9/5 (5,201 Views . 12 Votes)
40-50 amp

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Keeping this in view, how many amps do you need for a tankless water heater?

120 amps

Similarly, does a tankless water heater need a dedicated circuit? A tankless water heater will require a dedicated circuit as specified by the installation manual of the unit that has been selected. If you need additional space in the panel for the circuit breaker then a quad circuit breaker may be allowed as specified by the make and model of the panel.

Beside above, what size breaker do I need for a 220 volt water heater?

A water heater of this type is required to be considered a continuous load meaning that the branch circuit needs to be calculated at 125% of the heater's rated ampacity. 4500/240 = 18.75 amps, will work on a 20 amp OCPD but, 18.75*125% = 23.4 amps, requires a 25 or 30 amp circuit.

What size breaker do I need for a 240 volt water heater?

Since this is a purely resistive load 5500 watts at 240 volts is 23 amps, breaker is sized at 30 amps and 10 awg wiring is used. In your case if the elements are strapped for 4500 watts draw is 18.75 amps, permanent draw loads should be sized at 80% of breaker capacity so a 20 amp breaker is limited to 16 amps.

39 Related Question Answers Found

What is the downside of a tankless water heater?

Tankless water heaters produce an endless supply of hot water, take up less space, have a lower risk of leaking, are safer, and have a significantly longer lifespan on average. The main disadvantage of tankless water heaters is their upfront cost (unit and installation) is significantly higher than tank-style heaters.

Does tankless water heater use more electricity?

Electric tankless heaters are 99 percent efficient. The worst traditional electric heaters are 93 percent efficient. Tankless water heaters that use natural gas are about 23 percent more efficient than a traditional storage version, which is about 60 percent efficient, according to the Department of Energy.

Is it hard to install a electric tankless water heater?

Gas or Electric
Electric tankless water heaters are cheaper than the gas versions. Installation is easier and less expensive, and they're generally not as difficult to maintain as gas models. Keep in mind, however, that most conventional gas tank water heaters were not installed with a tankless retrofit in mind.

How many watts does it take to run a tankless water heater?

One whole-house tankless water heater has four 7,000-watt elements, for a total electrical load of 28,000 watts. This load re- quires wire and a circuit breaker that will handle at least 120 amps, at a cost many times that of electrical service to a conventional tank water heater.

Is 200 amps enough for a house?


200-amp service provides enough power for an electrical heating system, electrical appliances, plus general lighting and receptacle circuits. In large homes, 400-amp services are used with very extensive electric heating plus electrical appliances and lighting and receptacle circuits.

How do I size a tankless water heater?

How to Select the Right Size Tankless Water Heater
  1. Determine the maximum number of devices you want to run and their total flow rate. Then, add up their flow rates (gallons per minute).
  2. Determine required temperature rise.
  3. Sizing Example: An average shower will be between 104–106° and uses 2.6 gallons of water.
  4. Other Sizing Notes.

What are the requirements for a tankless water heater?

As a general rule of thumb any gas tankless water heater that uses internal combustion air musts have at least 10,000 cu. ft. of space around the unit. Confined areas (such as a closet) may require air ducts or additional air inlets.

What size breaker do I need for a 3000 watt water heater?

A 3000 watt 240 volt can be operated on a 14/2 cable, 15 amp double pole breaker.

What size wire do I need for a 30 amp breaker?

Any circuit fused for 30 amps must use a minimum of 10 ga copper or 8 ga alu. Longer runs may require an upgrade of wire size. In your case, use at least 10 copper for your welder regardless how far it is from the breaker panel.

Can I use a 40 amp breaker on 10 gauge wire?


You can play with all the math you want to, but you can't escape the fact that a #10 wire is rated to carry a maximum of 30 amps and will not be protected by a breaker which won't snap until more than 40 amps hit it.

Should I get a 4500 or 5500 watt water heater?

(1) If your heater has 4500 watt elements then that's running the breaker and wire at cooler temperature than 5500 watt. .Therefore, from conservation perspective the 4500 watt is better than 5500 watt.

What size breaker do I need for a 50 gallon water heater?

The standard for water heater circuits is #10, two conductors with ground (10/2) and a 30 amp circuit breaker for a water heater.

What gauge wire do I need for 220 volts?

If you're wiring a 220v, 20-amp outlet to run power tools, you can use the same 12-gauge wire you would use for a 110-volt, 20-amp circuit. Remember that the cable must have an extra hot wire. If the appliance draws 30 amps, you need a different type of receptacle, and the cable needs to be 10-gauge.

How many amps does a 40 gallon water heater pull?

So a 16 amp heater should be wired and protected by a 20amp circuit or a 20 amp breaker should only feed a max of 16 amp load. Bottom line, For a 4500w heater w/240v it will draw 4500/240 or 18.75 amps so #10 wire and either 25 or 30 amp breaker, depending on code.

What size breaker do I need for a dual 4500 watt water heater?


4500 watt elements REQUIRE 30 Amp dual pole breaker and 10 Gage wire size.

What size breaker do I need for a 2000 watt water heater?

The bottom line is, a 2000 watt 120 volt water heater should be on a 30 amp circuit consisting of #10 wire and a 30 amp single pole circuit breaker.

Why are tankless water heaters so expensive to install?

Installation is expensive because the unit needs a bigger gas supply than a conventional water heater does, and it needs to run its own exhaust flue to the exterior. Installation costs can vary widely, depending on the location of the flue and the gas supply. The unit itself costs between $800 and $1,000.