How to Wire an Electric Hot Water Heater

Whether it's for new construction or the replacement of a unit that has seen better days, completing the wiring for an electric hot water heater doesn't have to be difficult. Since many people choose not to open the main electrical panel, but instead feel more comfortable having a licensed electrician do it, steps will begin with the assumption that the main wiring for the water heater is already installed or hooked to an adequate power source and ready to be connected to the new electrical water heater unit.

Difficulty: Moderate

Instructions

Things You'll Need:

• Volt meter Screwdriver (Phillips or regular) Wire strippers Wire nuts

1. Turn off the electrical power to the wires and conductors that will be used. If unsure use a volt meter to verify that the power is indeed off.

2. Locate the factory water heater wires by using the appropriate screwdriver to remove the electrical junction cover of the water heater. There will be two insulated wires that may be of different colors, and either a green grounding wire or a green grounding screw.

3. Route the power source wires through the hole in the electrical housing that is designed for a wire connection. This is located on the top of the water heater.

4. Prepare the ends of all source wires and all factory water heater wires for connection by using the wire strippers to remove approximately 3/4 inch of the outer insulation, thus exposing the bare wire.

5. Place one of the partially stripped insulated source wires and one of the partially stripped insulated factory water heater wires into a wire nut and firmly twist clockwise until both wires are secure. Make sure there is no bare wire exposed past the bottom edge of the wire nut. Repeat this step for the second set of partially stripped insulated wires.

6. Make the grounding connection. If the grounding connection on the water heater is a wire, then place the partially stripped green grounding water heater wire and the grounding power source wire (which is either green or bare) into a wire nut and firmly twist clockwise until both wires are secure. If however, the grounding connection on the water heater is a screw, then take the grounding power source wire (which is either green or bare) and wrap it once around and underneath the screw head and then tighten the screw with a screwdriver to secure the wire.

7. Gently place all wires back into the electrical junction box on the top of the water heater and replace cover. Now the water heater is completely wired and ready to be filled with water before the main power source is turned back on.

Tips & Warnings

• Make sure all wiring is done in accordance with local and national electrical codes. Having a variety of wire nut sizes available can make tying wires together easier.
• Never wire a water heater without verifying that the power source is completely shut off.