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How to Wire a Hot Water Heater (with Pictures and Video)


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Installing a new electric water heater will require you to wire it to your home's electrical panel. Although this may sound intimidating, knowing how to wire a hot water heater is a skill that can be easily learned. Especially if you enjoy DIY projects.

This article will take you through the process step-by-step, and provide you with a video to help explain any additional questions you may have. 

1.	Disconnect The Water Heater From The Power Source

How to Wire an Electric Hot Water Heater

Whether you're replacing an old water heater or installing a new one for the first time, your electric water heater will need to be wired to your electrical panel.

It's important to note, that you'll be working with electricity. If done incorrectly, you could cause harm to the appliance, your home, and most importantly, yourself.

If you're not comfortable, and feel this is out of your skill set, you should hire a professional to wire your hot water heater for you. Safety is always more important that saving a few dollars.

Step-by-Step Guide

Water heater breaker at the electrical panel

Step One - Electrical Panel

  • Before starting, turn off the breaker in your home's electrical panel. Be sure to mark it so no one accidentally turns it on
  • In most cases, the breaker used for a water heater is a 2 pole, 30 AMP, 240 volt circuit breaker
  • Generally 10-2 type NM cable with 2 conductors and ground is typically used to wire water heaters
  • Check the specifications for your water heater for more information regarding electrical circuit and watt requirements
Water heater junction box with external ground screw

Step Two - Junction Box

  • The wiring connections to the water heater are made at the junction box, which is typically located on the top of the appliance
  • When replacing an existing water heater, you may find an external ground screw on top of the junction box. Remove the screw and wire to access the junction box
Wiring to wire water heater

Step Three - Wiring

  • If you're doing a new install, you'll need to run 10 gauge copper wire from your electrical panel to the water heater using Electrical Metallic Tubing (EMT) and/or Electrical Flex
  • However, if you're replacing a water heater, you should be able to use the previous wiring 
Connecting the water heater wiring

Step Four - Connect the Wiring

  • Inside the electrical junction box on top of the water heater, you should find a black and red wire, as well as a green screw
  • If your wires look different, you should test the them to determine the proper connections
  • Connect the red wire to the red wire, and the black wire to the black wire using wire nuts
  • Connect the ground wire to the green screw

Watch the Video

Other Resources

Here are a few helpful resources that will dive into other related topics to provide additional information:

Red Plumber Wrench

Emergency Plumbing - 24/7 Service

Repair - Install - Replace


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