Wiring Requirements for Electric Hot Water Heaters

Wiring Requirements for Electric Hot Water Heaters

Electric hot water heaters must be wired the right way or else you can risk serious injury

By Sabah Karimi

Plumber testing water heater element with meter
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The wiring requirements for electric hot water heaters vary only slightly by manufacturer, and a new water heater installation or replacement may require the assistance of a plumber, electrician and general contractor. A water heater's wires must be installed and configured correctly in order to safely connect the water tank to the heating elements.


The wires used to connect the hot water heater panels to the thermostat and heating elements include a ground wire, a black wire and a white wire. An electric hot water heater does not require a neutral wire because it does not demand a high-voltage load. The white wire is typically the "hot wire" in the circuit. These wires are connected to a junction box located on the side or top of the hot water heater.

Types of supplies

The most common supplies and materials used for wiring an electric hot water heater include: electrical wire connectors, needlenose pliers, electrical tape, twist ties, lock nuts, clamp screws and cables. In most cases, the electric wires are connected through the knockout on the junction box and secured in place using an electrical wire connector.


Once the power supply to the water heater has been turned off, the wires must be connected to the electrical supply according to the manufacturer's instructions. The electrical access plate on the hot water heater must first be removed with a screwdriver and pliers, and the electric wires can be run into the panel and attached using wire nuts. The bare copper or the ground wire can then be connected to the ground screw to complete the circuit.


When working with the wires and electrical panels of the water heater, it's important to close all the valves of the water heater or turn off the main water line to the house. This will prevent any water leaks and electrical safety issues when working with the water heater's wiring system. The water heater must be wired according to manufacturer's instructions. Failure to comply with the manufacturer's instructions can result in electrocution or faulty valve performance, and increases the risk of a home fire.


When you are replacing the water heater in your home, an electrician will be able to use the existing circuit system to wire the new electric water heater. If you want to install a new electric water heater or replace a gas heater, an electrician may need to work with a general contractor to design and implement a new circuit with an amp breaker and cables.

About the Author

Sabah Karimi is a regular contributor to DexKnows.

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