A tripped circuit breaker can be frustrating to deal with. When your circuit breaker keeps tripping, finding the culprit can be a challenge. If your air conditioner or heat pump unit is the culprit that caused a circuit overload in your home or office, there are a few possibilities to explore.
These circuit breakers, found in your electrical panel are safety devices that protect the electrical wiring from further damage and homeowners from electrical shocks. In this article I’ll talk about two common reasons for circuit breaker trips — earth leakage and overcurrent — and help you with troubleshooting this electrical current issue.
Tripped Circuit Breaker Due to Earth Leakage
The earth leakage circuit breaker (ELCB) that trips the electrical power to the house when a lightning strike happens can easily be restored. Switch the lever from the OFF position back to the ON position.
In the case of faulty air conditioner equipment, the ELCB may trip due to earth leakage. In this case, you will need to isolate the cause of the power outage or repair the equipment before the flow of electricity can be restored to the entire home.
Here are some of the most common reasons that cause the earth leakage circuit breaker to trip.
The motor wires in the compressor touch the metal enclosure of the compressor. The wires of the compressor motor may come off due to excessive vibration or faulty design.
Once these wires that are connected to the hot circuits touch the metal enclosure which is grounded, current flowing to the ground causes the ELCB to trip.
Disconnect the electrical service power and all the circuits to the terminal of the compressor. Use a multimeter and set the scale to measure resistance. Check the resistance between each of the terminals to the enclosure.
If the reading is close to zero, that means that the exposed wire closest to that terminal has touched the metal frame. Repair the fault or replace the compressor before the equipment can be operated again.
Similarly, if the fault is due to the compressor fan motor or indoor blower motor, disconnect the power and isolate the circuits to the motor. Check the resistance of each terminal to the casing (if metal). If it is close to zero, that means that the exposed wire is touching the casing, causing it to trip. Remove the motor for repair or replace with a new motor before the equipment can be operational again.
In circuits that have live, neutral, and earth wires bundled together, there is a possibility that the insulator of the wires breaks down (due to overheating, faults, under specs or inferior wires). This breakdown causes the live or neutral conductor to touch the earth conductor. This will cause the circuit breaker to trip. Troubleshooting this problem is more complicated as it involves electrical circuits and not particular components.
Tripped Circuit Breaker Due to Overcurrent
If the miniature circuit breaker (MCB) trips, the fault could be an overcurrent or short circuit. An issue with the air conditioner may cause this circuit breaker to trip after it has been running for a while. This issue will take more time to troubleshoot as the problem does not happen immediately. Here are the possible causes.
Disconnect the mains power before checking the connecting power from the mains to the equipment. For example, if there are 3 terminals that connect the power to the compressor, open up the housing and check the connection.
Look out for darkened or black spots on the terminal indicating that an overcurrent has occurred. A loose connection will cause arching, thus drawing excessive supply and damaging the wires and the parts that are connected to it.
Tighten the connection after removing and reconnecting the wire that has been damaged due to overheating.
A licensed electrician will usually be able to troubleshoot this problem by using a tong clamp ammeter to measure the current of that particular conductor.
If the compressor has a mechanical part that malfunctions causing it to lock, the current to operate will be a few times more than the normal operation. When this happens continuously, the possibility of over-current to happen will occur, causing the circuit breaker to eventually trip after a certain period of operation.
If the compressor or fan motor uses a 3-phase induction motor, a loss of one phase will cause overheating to occur when operating at full load. If the thermal overload protection does not trip, the circuit breaker will trip if the current exceeds its specification. A good design has a phase loss protector built into the circuit to prevent the motor from running in the first place.
Effectively troubleshoot a tripped circuit breaker with a methodical and safe approach. For earth leakage issues, identify the faulty components such as the compressor or fan motor, or issues like shorted wires. Isolate the equipment, perform resistance checks with a multimeter, and repair or replace faulty parts. For overcurrent problems, pay attention to loose wire connections, potential compressor lock, and phase loss in three-phase systems. Make sure all connections are secure and verify the mechanical integrity of the compressor to prevent recurrent trips in your electrical system.
Circuit breakers are vital for protecting electrical circuits from damage, preventing electrical fires and electrical shocks. Perform regular maintenance and make repairs promptly to avoid future problems with tripped breakers.
Electrical safety is a priority when addressing electrical issues. I recommend you contact a qualified licensed electrician to repair your main breaker issues. The expertise of a professional electrician guarantees protection from electrical fires, overloaded circuits, and prolongs the lifespan of your equipment.
