Why does my air conditioner keep tripping the circuit breaker? Your air conditioner might be tripping the circuit breaker because it is pulling too much electricity, a problem known as an AC overload or high amp draw AC. This can happen for several reasons, including a faulty AC capacitor, a serious AC compressor problem, dirty AC coils, a frozen evaporator coil, an AC fan motor failure, a short circuit AC unit, AC wiring issues, or even an undersized circuit breaker AC that isn’t strong enough for your unit.
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Apprehending Circuit Breakers
Think of a circuit breaker like a safety guard for your home’s electrical system. It protects wires from getting too hot. When too much electricity flows through the wires, the breaker stops the power. This stops the wires from overheating. Overheating wires can cause fires. So, the breaker trips or “flips off” to keep you safe.
Your air conditioner needs a lot of power. It usually has its own breaker. If the AC tries to use more power than the breaker can handle, the breaker does its job. It trips. This tells you something is wrong.
What Makes an AC Use Too Much Power?
Many things can make an air conditioner work too hard. When it works too hard, it pulls more electricity. This extra pull is a high amp draw AC. It’s like trying to run too many strong machines on one small power cord. The cord gets hot. The breaker is there to prevent that. Let’s look at common reasons this happens.
A Grasp of AC Overload
AC overload simply means the air conditioner is trying to use more power than the electrical circuit is made for. This is the main reason a breaker trips. The AC unit needs a certain amount of electricity to run normally. If something goes wrong, it can demand much more. This sudden need for high power causes a high amp draw AC. The breaker sees this high draw. It trips to prevent danger.
Analyzing a Faulty AC Capacitor
The capacitor is a small part in your AC. It looks like a battery or a soda can. It helps the AC motor start. Especially the large motor in the compressor. It gives the motor a powerful electrical push to get it going.
If the capacitor is weak or faulty AC capacitor, it cannot give that strong push. The motor still tries to start. But it struggles. When a motor struggles to start, it pulls a lot more electricity than normal. This creates a high amp draw AC. The breaker detects this high draw. It trips to protect the motor and the circuit.
- Signs of a bad capacitor:
- The AC unit hums but does not start.
- The fan runs, but the compressor does not.
- The breaker trips right when the AC tries to turn on.
- The AC unit starts but trips the breaker after a few minutes.
A technician can test a capacitor. It’s a common part to replace.
Investigating an AC Compressor Problem
The compressor is like the heart of your air conditioner. It pumps the stuff that cools the air (refrigerant). It’s a very big motor. It needs a lot of power to start and run.
If there is an AC compressor problem, it can cause the breaker to trip. A compressor can fail in different ways:
- Hard Starting: The compressor motor is having trouble beginning its work. This is often linked to a weak capacitor. But it can also be a sign the compressor itself is getting old or failing. A hard-starting compressor pulls huge amounts of electricity for a moment. This is a high amp draw AC. It can instantly trip the breaker.
- Locked Rotor: This is a serious problem. The compressor motor is stuck. It cannot turn. When power is sent to a locked motor, it pulls maximum electricity. This creates an extremely high amp draw AC. The breaker will trip very quickly to save the motor from burning up.
- Internal Electrical Fault: The motor windings inside the compressor could be damaged. This could be a partial short circuit inside the compressor motor itself. This causes uncontrolled high electricity flow. This is a specific type of short circuit AC unit problem contained within the compressor. It will cause the breaker to trip.
- Overheating: If the compressor gets too hot, it can pull more power. Overheating can happen if the AC unit is low on refrigerant, or if the outdoor unit (condenser) is blocked or dirty.
Compressor problems are often expensive to fix. Sometimes, replacing the whole AC unit is needed.
Deciphering Dirty AC Coils
Air conditioners have two main sets of coils:
- Evaporator Coil: Inside your home. It gets cold to cool the air.
- Condenser Coil: Outside your home. It releases heat from the house into the outdoor air.
Both sets of coils need airflow to work right.
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Dirty Condenser Coils: The outdoor coil gets dirty from dust, leaves, grass clippings, and pollution. Think of it like a car radiator getting clogged. The AC cannot release heat properly. This makes the whole system work harder. The compressor has to pump against higher pressure. This extra work makes the compressor pull more electricity. This is a high amp draw AC and an AC overload situation. It can make the breaker trip. Cleaning the outdoor coil is important maintenance.
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Dirty Evaporator Coils: The indoor coil can get dirty too, especially if you don’t change your air filter often. Dirty evaporator coils block airflow over the coil. This can also make the system work harder. It can even lead to the next problem: a frozen coil.
Keeping both dirty AC coils clean helps your AC run better and use less power.
Fathoming a Frozen Evaporator Coil
Sometimes the evaporator coil inside your home gets too cold. It can get covered in ice. This is a frozen evaporator coil. Ice forms when airflow is blocked or when the refrigerant level is low.
- Why ice forms:
- Dirty air filter (most common).
- Blocked return air vents.
- Dirty evaporator coil itself.
- Low refrigerant charge.
- Problem with the blower fan.
When the coil is frozen, airflow stops or is very low. The system still tries to cool. The compressor keeps working. But the ice makes it work much harder. It tries to push refrigerant through blocked paths. This extra stress can make the compressor pull too much power. This results in a high amp draw AC. The breaker trips because of this AC overload.
If you see ice on your indoor coil or lines, turn the AC off. Let the ice melt completely. Then, check your air filter and airflow. If it freezes again, you likely need a technician to find the cause.
Examining an AC Fan Motor Failure
Air conditioners have fans:
- Blower Fan: Inside your home. It pushes cooled air through your ducts.
- Condenser Fan: Outside unit. It pulls air over the hot condenser coil to remove heat.
If one of these fan motors fails or is having trouble, it can cause problems that lead to the breaker tripping.
- Failing Fan Motor: A fan motor that is failing might struggle to start or run. Like the compressor, a struggling motor pulls more power. This is a high amp draw AC. The breaker might trip when the fan tries to start or while it’s running.
- Fan Failure Impact on Compressor: If the condenser fan (outdoor) fails, the condenser coil cannot release heat. The compressor gets very hot and works against high pressure. This puts massive strain on the compressor. It will pull much more power and likely cause an AC overload. This will trip the breaker.
- Blower Fan Failure Impact: If the blower fan (indoor) fails, air does not move over the cold evaporator coil. This will quickly lead to a frozen evaporator coil. As discussed, a frozen coil makes the compressor work too hard, causing a high amp draw AC and tripping the breaker.
So, an AC fan motor failure can directly or indirectly cause the breaker to trip.
Pinpointing a Short Circuit AC Unit
A short circuit AC unit is a serious electrical problem. It happens when electricity takes a wrong path. Instead of flowing through the motor or other parts it is supposed to power, it finds a shortcut. This shortcut usually has very little resistance.
When electricity flows through a path with very little resistance, the current (flow) becomes extremely high instantly. This is a massive high amp draw AC. It happens much faster and is much higher than an overload from a struggling motor.
A short circuit can be caused by:
- Damaged wires (frayed, cut, melted).
- Loose wire connections that touch other metal parts.
- Water getting into electrical parts.
- Pest damage to wires (like rodents chewing).
- Internal failure in a motor, transformer, or control board.
The breaker is designed to trip instantly when a short circuit happens. This prevents wires from melting and starting a fire. If your breaker trips the moment the AC is turned on, or if you hear a pop or see a flash, it could be a short circuit AC unit. This needs immediate attention from a qualified electrician or HVAC technician.
Understanding AC Wiring Issues
Beyond a direct short circuit, other AC wiring issues can cause breaker trips.
- Loose Connections: Wires connect to the breaker, the disconnect box (a switch near the outdoor unit), and inside the AC unit. If these connections are loose, they can heat up. They create resistance. This can cause voltage problems or heat that trips the breaker over time. Loose connections can also arc (spark), which is very dangerous and can cause fires or short circuits.
- Damaged Wiring: The wires running from the breaker panel to the AC unit can be damaged. They might be old, or insulation could be rubbed off. This could be inside walls, in the ground, or exposed near the unit. Damaged wires can lead to short circuits or AC overload if they are not carrying power correctly.
- Wrong Wire Size: If the wires used to connect the AC are too thin for the amount of power the AC needs, they will overheat. The breaker is there to protect the wire as well as the appliance. If the wire is too small, it will get hot even with normal AC use. The breaker might trip due to this heat or if the AC has a temporary high amp draw AC.
Wiring issues are serious. They are often hidden. A technician or electrician needs to check the wiring from the breaker box all the way to the AC unit.
Interpreting an Undersized Circuit Breaker AC
Sometimes the problem isn’t the AC unit itself. It’s the circuit breaker. If the breaker is too small for the AC unit’s power needs, it will trip even when the AC is working normally. This is an undersized circuit breaker AC.
Every AC unit has a rating plate. It says how much power it needs (Locked Rotor Amps – LRA, Minimum Circuit Amps – MCA, and Maximum Overcurrent Protection – MOP).
The breaker size should be matched to the AC unit’s MOP rating or within a specific range based on MCA. If the installed breaker is smaller than the MOP rating, it will likely trip often. It might trip especially during start-up when the AC naturally has a temporary high amp draw AC.
Example: An AC unit might require a 30-amp breaker. If it was accidentally installed on a 20-amp breaker, that 20-amp breaker will trip easily because the AC needs more power than 20 amps, even when running correctly.
This is an installation error. An electrician can check the AC’s rating plate and the breaker size. They can replace the breaker with the correct size if it is undersized circuit breaker AC. (Important: Never put in a larger breaker without confirming the wire size is also correct and rated for the larger breaker. This is a fire hazard).
Summarizing the Common Causes
Here is a quick look at why your AC might trip the breaker:
| Problem | What It Is | How it Trips Breaker | Common Signs |
|---|---|---|---|
| Faulty AC Capacitor | Helps compressor start. | Fails to give strong start push, motor struggles. | AC hums but won’t start; trips on start-up. |
| AC Compressor Problem | Heart of the AC, pumps refrigerant. | Struggles, gets stuck, or has internal fault. | Loud noises from outdoor unit; trips on start or soon after. |
| Dirty AC Coils | Release/absorb heat. | Block airflow, make system work harder. | Poor cooling; AC runs long time; trips after a while. |
| Frozen Evaporator Coil | Indoor coil covered in ice. | Blocks airflow, makes compressor work hard. | No cold air; ice on indoor coil/pipes; trips after a while. |
| AC Fan Motor Failure | Fans move air over coils. | Fan struggles or stops; causes overheating/ice. | Outdoor fan not spinning; no air from vents; trips. |
| Short Circuit AC Unit | Electricity takes wrong, easy path. | Huge, sudden spike in electricity. | Breaker trips instantly; pop or flash seen/heard. |
| AC Wiring Issues | Loose, damaged, or wrong-size wires. | Creates heat, resistance, or wrong power flow. | Hot wires/outlets; flickering lights; trips over time or instantly. |
| Undersized Circuit Breaker | Breaker is too small for the AC’s needs. | Trips with normal AC power use, especially start. | AC runs briefly then trips, always uses same breaker. |
All these issues can cause a high amp draw AC or a short circuit AC unit. Both make the breaker trip to protect your home.
Simple Checks You Can Do (Safely!)
Before calling for help, you can do a few safe checks.
- Check the Breaker: Is it fully tripped? It will be between ON and OFF. Push it firmly to OFF, then firmly to ON. Does it trip right away? Or does it trip after a while?
- Check the Filter: A dirty air filter is a top cause of problems. Turn the AC off. Find your air filter (usually near the indoor unit or a large return vent). Is it clogged with dust? Change it if it is. This is easy and cheap.
- Check Airflow: Make sure supply and return vents inside are open. Make sure there are no large objects blocking airflow around the indoor unit.
- Check the Outdoor Unit: Turn the AC off at the thermostat AND at the disconnect switch near the outdoor unit. Look at the outdoor unit. Is it buried in leaves or dirt? Is there stuff piled right against it? Clear away anything blocking the sides or top. Use a hose to gently spray dirt off the outside fins (make sure power is OFF!). Do NOT spray water directly into the electrical parts.
- Look for Ice: With the AC OFF, look at the large copper pipe going into your indoor unit. Look at the indoor coil if you can safely see it. Is there ice? If yes, keep the power OFF to the AC (just the AC, not your whole house) and let it thaw. This can take hours. Once thawed, change the filter and restart. If it freezes again, call a pro.
These simple steps might fix the issue, especially dirty AC coils or a frozen evaporator coil from a dirty filter.
When You Need a Professional
Most of the time, a tripping breaker means a problem that needs a trained HVAC technician or an electrician. Do NOT try to fix electrical parts, capacitors, or compressors yourself. This is dangerous.
Call a professional if:
- The breaker trips right away after you reset it.
- You hear strange noises from the AC unit (loud hum, grinding, clicking).
- You smell burning.
- The outdoor fan is not spinning when the AC is on.
- You see ice and changing the filter does not fix it.
- You suspect AC wiring issues or an undersized circuit breaker AC.
- You think there is an AC compressor problem or AC fan motor failure.
- You suspect a short circuit AC unit.
- You don’t feel safe checking things yourself.
A technician has the right tools to measure power draw (high amp draw AC), test components like the faulty AC capacitor, find short circuit AC unit sources, and diagnose complex issues like an AC compressor problem or AC fan motor failure. They can safely check for AC wiring issues and confirm if you have an undersized circuit breaker AC.
Stopping Future Tripping
Once the problem is fixed, good maintenance can help prevent it from happening again.
- Change Filters: Change your air filter regularly. At least every 1-3 months. This is the easiest way to prevent frozen evaporator coil and dirty AC coils.
- Clean Coils: Have a technician clean your AC coils as part of regular service. You can gently clean the outdoor coil yourself, but a deep clean requires special tools and chemicals.
- Check Airflow: Keep return vents clear. Do not block indoor vents.
- Scheduled Maintenance: Get your AC checked by a professional every year. They can catch small issues like a weakening faulty AC capacitor or potential AC fan motor failure before they cause a breaker trip or an AC overload. They can also check refrigerant levels, which helps prevent frozen evaporator coil and stress on the AC compressor problem.
- Keep Outdoor Unit Clear: Make sure plants, fences, or stored items are not too close to the outdoor unit. It needs space to breathe.
- Listen to Your AC: Pay attention to strange sounds. They can be early signs of a problem.
Taking care of your AC unit helps it run smoothly. A well-running AC is less likely to have a high amp draw AC or other issues that trip the breaker.
Delving Deeper into Specific Issues
Let’s expand a bit more on some of these issues to show how they cause the breaker to trip.
More on High Amp Draw AC and AC Overload
Every electrical appliance is designed to use a certain amount of electricity (measured in amperes, or amps). This is its normal operating amp draw.
When something goes wrong, like a motor struggling or blockage in the system, the AC has to work much, much harder. This extra work translates directly into needing more electricity. It pulls a higher number of amps than normal. This is the high amp draw AC.
The circuit breaker for the AC is rated for a specific maximum amperage. For example, a 30-amp breaker can handle up to 30 amps (or a bit more for a short time, like during start-up). If the AC unit, because of a problem, tries to pull 40 or 50 amps, the breaker sees this AC overload. Its internal mechanism (usually a bimetallic strip that heats up or a magnetic coil) detects the excessive current and quickly trips, cutting off the power.
This tripping protects the motor windings inside the compressor or fan from burning up. It also protects the wires from overheating, which could melt their insulation and start a fire. The high amp draw AC is the immediate cause of the trip, but the underlying problem (faulty capacitor, bad compressor, dirty coils, etc.) is what causes the high amp draw.
Understanding the Severity of a Short Circuit AC Unit
A short circuit AC unit is different from an overload. An overload is pulling too much power because the unit is working hard. A short circuit is electricity flowing where it shouldn’t.
Imagine water in a pipe. Normal flow is like water going to your faucet. A short circuit is like the pipe bursting right at the start, with water spraying out everywhere uncontrolled.
In electricity, when a hot wire touches a neutral wire, a ground wire, or the metal casing of the unit (which is connected to ground), it creates a path of very low resistance. Electricity follows the easiest path. This low-resistance path lets a massive amount of current flow very, very quickly. This current can be hundreds or even thousands of amps for a fraction of a second.
The breaker’s job is to react extremely fast to this. Breakers have magnetic parts that instantly trip when they detect a sudden, massive surge of current like a short circuit. This is much faster than the heat-sensing part that trips on an overload. This rapid trip is crucial because uncontrolled current flow in a short circuit can cause wires to melt, explode, and start fires in milliseconds.
A short circuit AC unit is a clear sign of damaged components or wiring. It requires immediate professional diagnosis and repair.
More Detail on AC Wiring Issues
AC wiring issues are often overlooked but are very important for safety and preventing breaker trips.
- Loose Terminals: At the breaker, at the disconnect switch, and inside the AC unit, wires are held in place by screws or clamps. If these become loose over time (due to vibration, expansion/contraction from heat), the connection point becomes resistive. Resistance generates heat. Enough heat can cause the breaker to trip. Worse, arcing (electrical sparks jumping across a small gap) can occur at a loose connection. Arcing is a major fire hazard and can also cause sudden power surges that trip the breaker or damage the AC unit.
- Corrosion: Wire terminals, especially in the outdoor unit, can corrode due to moisture and chemicals. Corrosion increases resistance, leading to heat and potential trips.
- Improperly Spliced Wires: If wires were joined incorrectly using tape instead of proper connectors, or if the connections are exposed to moisture, it can lead to short circuits or high resistance.
- Physical Damage: Wires can be accidentally cut, pinched, or have their insulation damaged during other home repairs, landscaping, or by pests. Damaged insulation exposes the conductive wire, increasing the risk of a short circuit AC unit.
An electrician or HVAC technician checking for AC wiring issues will inspect all visible wiring and connection points. They might use special tools to check for loose connections or measure voltage drop, which can indicate resistance problems.
Clarifying Undersized Circuit Breaker AC
The National Electrical Code (NEC) and local building codes specify how circuits should be wired and protected. For an AC unit, the size of the breaker (the Maximum Overcurrent Protection – MOP) is determined by the manufacturer based on the unit’s power requirements, particularly the start-up surge of the compressor.
The MOP rating is on the AC unit’s nameplate. It’s a maximum size breaker you can use. There is also often a Minimum Circuit Amacity (MCA) which tells you the minimum wire size and breaker size needed. The actual breaker size installed is often the next standard size up from the MCA, but not exceeding the MOP.
If an undersized circuit breaker AC is installed (e.g., a 20A breaker on a circuit needing 30A), the breaker’s trip threshold is too low for the AC’s normal operation, especially during start-up. The breaker will frequently trip even though the AC unit itself isn’t necessarily faulty, just that the protection is inadequate (too sensitive).
While it might seem like a simple fix to just put in a bigger breaker, this is dangerous if the wires connected to that breaker are not also rated for the higher amperage. A bigger breaker on smaller wires means the wires could overheat and cause a fire before the breaker trips. Always consult an electrician to ensure both the breaker and the wiring size are correct for the AC unit.
Safety First!
Dealing with electrical systems is dangerous. High voltage can cause serious injury or death.
- ALWAYS turn off power at the main electrical panel before inspecting any wiring or components.
- If you are unsure about anything, call a professional.
- Do not ignore a tripping breaker. It’s a warning sign.
Tripping breakers are the system’s way of telling you there’s a problem. Finding and fixing the root cause is key to getting your AC running safely again.
Frequently Asked Questions (FAQ)
h4 Is it okay to just reset the breaker when it trips?
You can reset it once or twice. If it trips again quickly, especially right away or after only a few minutes, stop resetting it. Repeatedly resetting a breaker when there is a problem can damage the AC unit, the wiring, or even cause a fire. It means something is seriously wrong, like a short circuit AC unit or a bad AC compressor problem causing a massive high amp draw AC.
h4 Why does my AC trip the breaker only on hot days?
On very hot days, your AC works harder to cool your home. This means the compressor runs longer and builds up more heat and pressure. If there’s an underlying issue like dirty AC coils, a failing faulty AC capacitor, or a weakening AC compressor problem, the extra strain from the heat can push the system past its limit, causing a high amp draw AC and tripping the breaker.
h4 Can a dirty air filter really cause the breaker to trip?
Yes! A very dirty air filter blocks airflow over the indoor coil. This makes the coil get too cold and freeze (frozen evaporator coil). The ice blocks airflow even more. The compressor has to work much, much harder to move refrigerant through a system with poor airflow and high pressure from the blockage. This extra work causes an AC overload and high amp draw AC, tripping the breaker. It’s one of the most common, and easiest to fix, causes.
h4 My AC breaker trips, but the air coming out was cold before it stopped. What does that mean?
This often points to a problem that develops over time as the unit runs, rather than an instant electrical fault. It could be:
- An AC overload from dirty AC coils or a frozen evaporator coil slowly building up strain.
- A component like an AC fan motor failure causing the system to overheat after running for a while.
- A faulty AC capacitor that helps the unit start but fails while running, stressing the motor.
- An AC compressor problem that starts okay but struggles as it heats up.
These issues build up the high amp draw AC over minutes or hours until the breaker trips.
h4 Could pests cause my AC breaker to trip?
Absolutely. Rodents, insects, or other small animals can get into the outdoor unit or wiring. They can chew on wires, build nests that block airflow (leading to overheating and AC overload), or even create a short circuit AC unit by touching electrical components. Always check for signs of pests around your unit.
h4 The breaker for my AC is hot. Is that normal?
No, a hot breaker is NOT normal. It is a sign of a problem. A hot breaker means it is carrying too much current (high amp draw AC or AC overload), or there are loose connections at the breaker causing resistance and heat (AC wiring issues). A hot breaker is a fire risk. Do not touch it. Do not reset it. Call an electrician immediately.
h4 My AC unit is old. Is that why the breaker trips?
Older AC units are more likely to have problems that cause breaker trips. Components like the faulty AC capacitor, AC compressor problem, and AC fan motor failure wear out over time. Wiring can become brittle or connections loose (AC wiring issues). Older units were also less energy-efficient and might naturally have a higher amp draw than newer ones, making them more sensitive to any additional strain. If your AC is old and tripping the breaker, it might be time to consider replacement.
h4 Can low refrigerant cause the breaker to trip?
Yes. Low refrigerant (the stuff that cools the air) makes the AC system work much harder. The compressor has to pump against incorrect pressures. This extra strain causes the compressor to pull more electricity. This leads to a high amp draw AC and an AC overload, which can trip the breaker. Low refrigerant can also cause the frozen evaporator coil. Low refrigerant is a serious issue that harms the compressor and needs a professional to find and fix the leak and recharge the system.
This information should help you understand why your AC might be tripping its breaker and when you need to call for help. Safety is the top concern, so don’t take risks with electrical problems.