Electric Water Heater Wiring
How are the wires connected to a water heater? Common Wiring Methods for an Electric Water Heater, Basic Water Heater Circuit Requirements, Connect Water Heater Wiring.
Guide to Wiring an Electric Water Heater
- I’m wiring a electrical hot water tank.
- I have a 50 Amp wire to it out of the box is a white red and black and copper ground.
- Out of the hot water tank is only a red and black.
- Where does the white wire from the house hook up to?
This electrical wiring question came from: Nate, a Homeowner from Whittaker, Michigan.
Thanks for your electrical question Nate.
How to Wire a 240 Volt Residential Water Heater
Application: Wiring a 240 Volt 4000 Watt Residential Electric Water Heater.
Skill Level: Intermediate to Advanced – Best installed by a Licensed Electrical Contractor.
NOTE: Work in electrical panels is not recommended for homeowners, non-experienced individuals or non-electricians.
Tools Required: Basic Electricians Pouch Hand Tools, electric drill, auger bits and extension cord as needed depending on the scope of the project.
Estimated Time: Depends on personal level experience, ability to work with tools and install 240 volt electrical circuit wiring.
Precaution: Identify the main circuit of the panel, turn it OFF and Tag it with a Note before working with the wiring or installing the 240 volt wiring and circuit breaker.
Notice: Installing an additional 240 volt circuit should be done according to local and national electrical codes with a permit and be inspected.
Wiring a 4000 Watt Electric Water Heater for a Home
- Basic Home Electric Water Heater Circuit Requirements
- An conventional residential 240 volt electric water requires a dedicated circuit.
- The the typical circuit is a 30 amp 240 volt dedicated circuit.
- The circuit cable wiring includes two insulated wires designated as Line-1, Line-2 and the ground conductor.
- IMPORTANT: Not all water heaters are alike. Please consult the installation manual that is included with the water heater you have for specific installation instructions.
- Does a Water Heater Require a Neutral Wire?
- At this time, the conventional hot water heater does not require a neutral, however that will most likely change.
- Neutral wires are required for other 220volt and 240 volt appliances that have electronic controls that require a dedicated neutral, which is included with the 4wire cord.
- If the circuit wiring is supplied by a 4-wire cable, and there is a spare white wire then simply cap off the white wire with a wire connector fastened onto the end of the wire.
- Connect Water Heater Wires
- It is a very common practice to install a 10/2 Cable with a Ground Wire.
- The 10/2 cable actually has 3 wires including the ground wire.
- With this type of cable wiring method, the black and white wires are used for the 240 volt circuit, so the white wire is colored typically with either red or black electrical tape or a permanent marker.
- A conventional electric water heater will come with a black wire and a red wire which are connected to the wires of the same color as described above. The ground wire is attached to the green ground screw which is in the same wiring junction box compartment which is built into the top of the water heater.
- Protecting the Circuit from Overload Conditions
- Never use a cable that is too small for the water heater circuit, and be sure the circuit breaker is sized correctly for the circuit. Typically with #10 gauge copper wire a 2-pole 30 amp 240 volt circuit breaker is installed.
- If existing circuit wiring will be used for the water heater and the circuit is larger then the circuit breaker should be replaced with a 30 amp breaker. The rule of thumb is to size the circuit breaker for the smallest size wire type within the circuit, or as indicated on the equipment label or as instructed in the installation manual.
Sources and Citations
For more information about Home Electric Tank Type Water Heaters
More about Wiring 220Volt and 240Volt Circuits
220 Volt Appliance Wiring Requirements
See how some 220 volt appliances do not use a white common wire, instead they use two hots and a ground.