How to Connect an Electric Hot Water Heater

An electric hot water heater provides a reliable source of hot water in any home and are much easier to install than gas water heaters. While many people worry about the energy cost associated with an electric hot water heater, the truth is that in most areas, the cost of electricity and gas aren't all that different from each other. In addition, an electric hot water heater is often a safer appliance as it produces no carbon monoxide and doesn't need an exhaust line like a gas-powered heater. Installation requires only basic electrical experience.

Things You'll Need

• Screwdrivers
• Wire strippers
• NM cable stripper
• Wire connectors
• Voltage tester
• Electrical tape
• Hammer
• Needle-nose pliers
• NM cable connector

Instructions

1. Turn off the power to the circuit that will be feeding the electric hot water heater. Most residential electric hot water heaters are powered by a double-pole, 30-amp breaker.

2. Test the circuit wires with a touch-type voltage tester before you touch any of the them to ensure that the power to the circuit is off. Press the button on the tester and touch the tip of it to each wire to make sure the circuit is dead. If the tester beeps or lights up, then the circuit is still live. Try additional breakers until you find the correct one.

3. Remove the cover plate from the electrical box located on the top of the hot water heater. Inside the box you should see a black wire, a white wire and a green ground screw.

4. Loosen one of the knockouts located near the electrical box by tapping it with a hammer and screwdriver. The knockouts are circular depressions that once removed, allows the wire to enter the wiring box on the top of the water heater. Once the knockout is cracked loose, use the needle-nose pliers to remove it the rest of the way by twisting it back and forth.

5. Remove the locknut from the NM cable connector and insert the connector's threaded nipple into the hole left by the knockout. Secure the connector in place by tightening the locknut over the threaded nipple on the inside of the electrical box. Loosen the two clamp screws on the connector to allow room for the NM cable to fit through. NM cable, or Romex, is the flexible sheathed electric cable that consists of the black, white and ground wires. This is the electrical line that delivers power to the hot water heater from the main electrical panel.

6. Remove about 6 inches of outer sheathing from the electrical cable using a NM cable, also called Romex, stripper. If you don't have a NM cable stripper, just use a sharp knife to slice a thin cut in the tip of the insulation and pull it apart by hand. Trim off the excess sheathing with the knife.

7. Insert the electrical wires through the NM cable connector until the sheathed portion is through the clamp. Tighten the clamp down over the sheathed part of the cable, not the individual wires.

8. Remove 3/4-inch of insulation from the ends of each wire in the electrical box using the No. 10 slot on the wire strippers.

9. Wrap the bare ground wire (or green insulated wire) around the green ground screw in the electrical box and then tighten the screw down.

10. Connect the white circuit wire with the white wire from the hot water heater and secure them tightly with a wire connector so no copper is exposed. Wrap electrical tape around the connector for extra protection.

11. Connect the black circuit wire with the black wire from the hot water heater and secure them tightly with a wire connector so no copper is exposed. Wrap electrical tape around the connector for extra protection.

12. Return the electrical box cover to its position and screw it in place.

13. Turn the circuit breaker back on only if the tank is filled with water and set the temperature on the hot water heater to your liking.

Tips & Warnings

• Always test your tester on a circuit that you know is working before you test the circuit you are going to be working on. This is to ensure the tester is functioning properly.

• An electric hot water heater uses two current carrying wires and no neutral, so both the black and white wires will be carrying 120 volts once the circuit breaker is turned back on. Be very careful when working with 240-volt circuits. Always test them with a voltage tester before working with them and if you're not comfortable, hire a professional electrician to perform the job.