No, it is not okay. You will be building in a potential fire hazard. If a thermostat in your electric water heater fails, energizing both the upper and lower heating elements, your water heater’s current draw will continuously exceed #12 AWG NM-B wire’s 20 amp rating.

Can I use 12 2 wire on my hot water heater?

Electric hot water tanks require a wire size of 12 gauge AWG. This wire is rated for up to 20 amps of current. Most 120 volt electric water heater use a maximum of 15 amps 120 volt.

Can you use 12 wire on a 30 amp breaker?

You should not use a 30-amp circuit breaker on a 12-gauge wire. The circuit breaker installed on a circuit is of a specific size to protect a certain wire gauge. A larger breaker on a thinner wire will allow more current over the wire before tripping.

Will a 12 2 wire carry 30 amps?

Yes, based on the National Electric Code or NEC, you can use 12-2 AWG cables for THHN or THWN-rated wires. These cables are made for general purposes and can hold up to 194 degrees without taking any damage. It simply means these wires can withstand the heat temperature drawn by a 30 amp circuit breaker.

Can you use a 30 amp breaker for a water heater?

Electric water heaters require a dedicated 240-volt dedicated 30-amp circuit and a 10-2 non-metallic (NM) or MC cable. This means the breaker only powers the water heater and no other appliances. A 30-amp circuit breaker can power all 4500watt water heaters regardless of gallon size.

How many amps will 12 2 wire carry?

Maximum Breaker Size is 30 amps. You can use a 20 amp circuit breaker with 12/2 Romex as 12/2 wire is rated for 20 amps. Always remember THE BREAKER IS THERE TO PROTECT THE WIRE NOT THE APPLIANCE !!!

What wire do you use for 30 amps?

For a maximum of 30 amps, you’ll need a wire gauge of 10. The most common household item that requires a 30 amp circuit is a central air conditioner.

What kind of breaker do I need for a water heater?


Electric water heaters require a 240-volt dedicated circuit, which serves only the water heater and no other appliances or devices. The circuit wiring typically includes a 30-amp double-pole breaker and 10-2 non-metallic (NM) or MC cable.

What size breaker do I need for my hot water heater?

The breaker size has always been calculated by dividing the total wattage by voltage. So to know what size breaker for a 4500-watt water heater, we need to divide 4,500 by 240. The answer to this is the exact figure you get when you convert 4500 watts to amps: 18.75.

What size breaker should a hot water heater be on?

30-amp breaker

An electrical water heater typically uses a 30-amp breaker, so something like the Q230 30-Amp Double Pole Type QP Circuit Breaker will do the work well.

How many amps does a 30 gallon water heater use?

The branch circuit needs to be calculated at 125% of the rated ampacity for this type of water heater to be considered a continuous load. In order to work on a 20 Amp OCPD, you will need a 25 or 30 Amp circuit.

What size wire would you run for a 30 amp breaker connected to a electric water heater?

Electrical wires

Since the generic breaker size for water heaters is 30-amps, the best wire size is a #10 American Wiring Gauge (AWG).