How to Install a 240 Volt Electric Baseboard Heater

  • 01 of 02

    Electric Baseboard Heater Installation Introduction

    electric baseboard heater
    Electric baseboard heaters can provide confortable radiant heat. ©2016 Cadet

    Radiant heat is the most comfortable type of heat you can install in your home.

    There is hot water or hydronic baseboard radiant heat which uses a boiler for its heat source and electric baseboard radiant heat which uses line voltage and electrical resistance as a heat source

    They both work basically the same in that they heat air with small fins and through convection, air moves through the heating unit.

    There are several other options for electric heating in your home but electric baseboard heating is very common and fairly easy to install. They are most commonly used beneath windows to offset heat loss through the glass. Electric baseboard heating is also a great option as supplemental heat in hard to reach areas such as a 4-season porch.

    Planning Tips:

    When considering electric baseboard heat and planning for the project, here are some things to consider:

    1. The heater will work most effectively if placed directly beneath a window to offset the heat loss through the window.
    2. Make sure you do not locate the heater beneath an existing wall outlet.
    3. You have a choice of 120-volt units or 240-volt units. The 240-volt baseboard heater is a lot more energy efficient so that is what is recommend (and why it is the subject of this tutorial).
    4. You will need a dedicated 20 amp, a 240-volt circuit for the 240-volt baseboard heater. You should be able to power about 12 to 16 feet of baseboard with the 20 amp circuit.
    5. Baseboard heaters require a minimum of 1 inch of air space under the unit for the convective air flow to work properly.
    6. Maintain at least 12 inches clear from window coverings and furniture.
    7. Locate the thermostat on an interior wall and away from heat sources.

    Tools You Will Need:

    Some of the tools and supplies you will need for this tutorial include these items:

    1. Power drill/driver
    2. 1-1/2" drywall screws
    3. Tape measure
    4. Stud finder (optional)
    5. Wire cutter / needle nose pliers
    6. Wire stripper
    7. Voltage or multi-meter
    8. Drywall saw
    9. 240 volt 20 amp dual pole circuit breaker feeding the circuit through 12/2 NM cable
    10. Electrical tape
    11. Flat blade screwdriver
    12. Phillips head screwdriver
    13. 1/2" cable clamp connectors
    14. Wire nuts
    15. Torpedo level
    16. 240-volt baseboard heater and thermostat
      Compare Prices Electric Baseboard Heater

    OK, let's get to the installation...

    Continue to 2 of 2 below.
  • 02 of 02

    Installing an Electric Baseboard Heater

    electrical baseboard heater installation
    Electrical connections occur within the connection box. ©2016 Cadet

    Follow these summarized steps to install your electric baseboard heater with an integral thermostat. (NOTE: Always follow specific manufacturer recommendations).

    1. Turn off power to your main electrical panel and install new 240 volt circuit with a dual pole 20 amp circuit breaker and 12-2 NM wiring. If your model requires a 30 amp 240 volt circuit use 10 gauge 10-2 NM cable. You will need two hot wires and a ground wire.
    2. Remove wiring compartment cover on the baseboard heater. Determine baseboard mounting height per manufacturer's instructions (bottom of unit at least 1" above floor unless unit is designed to sit on the floor). Based on the mounting height, measure to distance FROM THE FLOOR to the center of the electrical knockout plug on the back of the unit. This is the vertical height that your electrical circuit cable needs to exit the wall.

      Locate the baseboard unit on the wall in its final position and measure over from  the EDGE of the unit to the center of the knockout plug. This is the horizontal dimension from the baseboard edge to the knockout.

      With the vertical and horizontal dimensions determined, run your new 240 volt circuit cable to exit the wall at this point.
    3. Remove the knockout on the back of the connector box with a flat blade screwdriver and install a 1/2" cable clamp firmly to the box. Run the 240 volt circuit cable through the cable clamp opening leaving 6" to 8" in length and strip the insulation from the ends back 1/2". Tighten cable clamp with a screwdriver.
    4. Test the circuit for proper voltage with a multi-meter by temporarily turning the circuit back on. Once proper voltage is confirmed, turn the circuit breaker back off.
    5. Your circuit Connect the ground wire to the green grounding screw in the connector box.
    6. Using a stud finder locate walls studs behind the baseboard heater and attach the heater to at least 2 wall studs using the 1-1/2" drywall screws. Use a torpedo level to level the unit if it is a type that is not floor mounted. (NOTE: If you have a floor mounted unit you may have to cut the baseboard where the heater goes in order to fit the unit against the wall).
    7. In the connection box there will be a factory wiring connection from the top of the unit to the electrical resistance finned heating element. Following manufacturer instructions, cut the factory power wire connection or disconnect the wire nut that hold the connection together.

      Using wire nuts, connect one factory wire to a hot power wire from the 240 volt circuit cable and the other factory wire to the second hot power wire from the 240 volt circuit cable.
    8. NOTE: If you have a unit with a remotely located line voltage thermostat the wiring must run from the 240 volt circuit breaker to the thermostat to the baseboard heater. See manufacturer directions for details on wiring that type of unit.
    9. Install connection box cover.
    10. Turn power on at the circuit breaker and test for proper operation