About the Post

Jerry Hardy

Author Information

I was a Building Contractor along with owning rental properties where I did most of the repairs myself. Its my pleasure to pass on to you some of the methods I had used in the past. Hopefully, this will save you the expense of hiring a professional to do the work.

Fixing Electric Baseboard Heater

electric baseboard heater


A baseboard heater operates on the principle of convection, cool air is drawn through the bottom of the heater and warmed by the heating element followed by warm air exiting the top of the heater. The heater operates by current sent from the circuit breaker to the heater thermostat. From the thermostat current flows to the heating element.


The response of the circuit breaker helps to reveal why the baseboard heater is malfunctioning.

1. Circuit breaker stays on until baseboard heater is turned on

If this is the case, the heater has a short to ground. Open the baseboard heater wiring compartment and check each wire for a burnt spot along with checking the insulation for any bare spots. Remove each wire connection and check for continuity between the wire connector at the housing and ground. If there is a green ground screw present, this makes a handy place to get a good ground connection for the tests. If there is continuity, replace the thermostat.

2. Circuit breaker stays on but baseboard heater not heating

The problem is either the thermostat, the heating element or the limit switch. With the circuit breaker off, open the wiring compartment in the heater. Disconnect the wires from each of the electrical parts including the thermostat ,if the heater has one built in, and the baseboard heating element. Mark all wires prior to disconnecting so there will be not confusion when re-installing the wires. Test the continuity through each part by placing one of the meter leads on the wire entering the part with the other meter lead connected to the exiting wire. If there is no continuity, replace the part.

3. Circuit breaker trips immediately when turned on with the heater off

This indicates that there is an electrical short between the circuit breaker and thermostat switch.

a. Check the wiring between the circuit breaker and heater thermostat for any signs of damage.

b. Look for burn signs on the thermostat and attached wires. If the thermostat has an appearance of overheating, replace it.

c. After disconnecting the wire leading to the thermostat, with a multimeter set on continuity, place one meter lead on the ground wire and the other to each of the insulated wires leading to the thermostat. If the meter shows continuity between any of the two wires, there’s a short. Replace the thermostat.

4. Circuit breaker trips after on for a short time with heater on.

If the breaker trips after staying on for a short time. it could mean that the wiring to the heater is not heavy enough to carry the load. This happens occasionally if the original heater was changed to a higher wattage heater requiring a heavier wire and a circuit breaker of higher amperage. 12 gauge wire with a 20 amp circuit breaker is sufficient for heaters less than 4000 watts. Heaters over 4000 watts require 10 gauge wire and a 30 amp circuit breaker.

5. Circuit breaker turns hot before it trips

A loose wire in the circuit will cause this or the buss bar in the circuit breaker is not making good contact. Re-tighten each wire attached to the circuit breaker. If the problem continues, replace the circuit breaker.

Replacing heater thermostat

Note: Before purchasing the new thermostat, check the existing one and try to purchase one similar for ease of installation.  They are available for both 120 and 240 volt baseboard heaters.

internal cadet thermostat

wall thermostat

wall mounted thermostat

1. Turn off power

Turn off the power at the breaker box or fuse panel. It is best to use a voltage tester or multimeter to be assured that the power is off.

2. Remove old thermostat

Prior to removing the existing thermostat, mark both the wires leading into and out of the thermostat.  This will aid you in installing the new unit.

3. Install new thermostat with marked wires

With the aid of the markings on the wires,  re-wire the the new thermostat as the old one was wired. Mount the baseboard heater thermostat.

4. Install new thermostat without marked wires

a.  View the back of the thermostat and you will see writing showing line and load connections. Connect the black(hot) line wire to the line side of the thermostat and the white wire to the thermostat load neutral position. The ground wire should be connected at the load ground position with a jumper wire to the heater ground screw.

b. Connect the black wire from the baseboard heater(load wire) to the load position on the thermostat. Connect the white wire from the heater to the load neutral position.

c. Mount the thermostat

d. Turn on power

e. Test thermostat

Turn the thermostat dial until you hear a click indicating that the contact has been made with power going to the baseboard heater element.  Place you hand on the heater to make sure that the baseboard heater is working.





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Fixing Electric Baseboard Heater

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