Kenmore Microwave: tripping breaker

Professional Repair Guide

What is this symptom?

Experiencing a tripping breaker with your Kenmore microwave can be frustrating and potentially dangerous. This issue usually occurs when the door is opened or closed, immediately upon pressing START, or after running for a brief period. Identifying the cause is crucial, as it may stem from faulty components like the door interlock switch or high-voltage parts. Addressing this promptly ensures safe operation and prevents further electrical issues.

Urgency: High

Important Tips for Kenmore Models

  • Kenmore-branded microwaves are often manufactured by other OEMs; however, repair sources that categorize 'Kenmore / Sears' microwaves consistently list door switch assemblies as the most common reason for breaker trips, followed by high-voltage capacitor and magnetron failures. Diagnosis and parts vary by model number prefix.

Possible Causes

Failed door interlock switch/monitor switch sequence (including shorted or misaligned door switch, or broken latch hooks) causing a direct short condition

How to Identify: Breaker trips when opening/closing the door or very soon after pressing START; door feels loose or doesn't latch crisply; switch continuity tests fail; visible wear on latch hooks; repeated breaker trips without the internal line fuse blowing is commonly reported with door switch faults.

Part: Door switch assembly (primary interlock switch, secondary interlock switch, monitor switch) and door latch hooks

Shorted high-voltage capacitor

How to Identify: Breaker trips immediately or within seconds after START is pressed (with the oven otherwise powering on and showing the clock; capacitor tests shorted with a multimeter after proper discharge; sometimes accompanied by a pop or burning smell.

Part: High-voltage capacitor

Shorted high-voltage diode

How to Identify: Breaker trips immediately when START is pressed; diode tests shorted/failed (requires proper HV discharge and correct test method; may occur along with HV capacitor issues.

Part: High-voltage diode

Magnetron shorted or failing (drawing excessive current)

How to Identify: Breaker trips shortly after START is pressed; may be preceded by loud humming, arcing sound, burning smell, or reduced heating before failure; magnetron tests shorted to ground with a multimeter (technician-level due to HV risks.

Part: Magnetron

Shorted high-voltage transformer (often accompanied by arcing/burnt odor)

How to Identify: Breaker trips when START is pressed; often a strong burnt smell, visible scorching, or buzzing/humming right before trip; transformer may show shorted windings or short to chassis (technician-level test.

Part: High-voltage transformer

Faulty turntable motor or cooling fan motor causing short or overload under load

How to Identify: Breaker trips after the microwave has been running briefly rather than immediately; abnormal noises from turntable/fan; motor tests shorted or seizes; sometimes trips only when the tray is installed and turning.

Part: Turntable motor / cooling fan motor

Overloaded circuit, weak breaker, or nuisance tripping with GFCI/AFCI protection (especially if sharing circuit with other high-draw appliances)

How to Identify: Microwave works on a different dedicated circuit/outlet; breaker trips mainly when other appliances are running; GFCI/AFCI trips more readily; breaker is warm or old; outlet shows signs of heat damage or loose fit.

Part: Home electrical circuit (breaker, receptacle, wiring) rather than microwave parts

DIY Solutions

Determine whether the trip is caused by circuit overload vs. an internal microwave fault (controlled isolation test)

Easy 10-20 minutes
  1. Unplug the microwave. Reset the tripped breaker (or GFCI/AFCI).
  2. Unplug or turn off other appliances/lights on the same circuit (coffee maker, toaster oven, kettle, space heater, etc.).
  3. Plug in only the microwave and try a short heat test.
  4. If it still trips with no other loads, the microwave likely has an internal short/failure and should not be used until repaired.
  5. If it does NOT trip when isolated but trips when other loads are present, the circuit may be overloaded or the breaker may be weak—consider moving the microwave to a dedicated 15/20A circuit or having an electrician evaluate.
⚠️ Safety First: Do not repeatedly reset and retry if the breaker trips instantly multiple times—this can indicate a dangerous short.

Identify timing pattern to narrow the likely failed subsystem (door vs. high-voltage section)

Easy 5-10 minutes
  1. Observe exactly when the breaker trips: (A) when opening/closing the door, (B) immediately when pressing START, or (C) after running for some time.
  2. If it trips at the door action (A), strongly suspect door interlock/monitor switch or latch alignment issues.
  3. If it trips at START (B), suspect high-voltage components (capacitor/diode/magnetron/transformer).
  4. If it trips after running (C), suspect motors/overheating/weak breaker or wiring issues.
⚠️ Safety First: Do not open the microwave cabinet; internal high-voltage components can store lethal charge even when unplugged.

Inspect outlet and plug for heat damage or loose connection (common external contributor)

Easy 10-15 minutes
Tools Needed: Flashlight
  1. Unplug the microwave.
  2. Inspect the plug blades for discoloration, pitting, or melting.
  3. Inspect the wall outlet for browning, melted plastic, looseness, or a burnt smell.
  4. If any damage is found, stop using the outlet and have it replaced by a qualified electrician before using the microwave again.
  5. If the outlet is on a GFCI/AFCI and trips frequently, test the microwave on a different non-GFCI/AFCI dedicated circuit (if available) to determine if nuisance tripping is occurring.
⚠️ Safety First: Do not continue using a damaged outlet or plug—this is a fire hazard.

Professional Repairs

Replace door interlock switch set and/or door latch assembly (correct interlock/monitor switch sequence)

Estimated Cost: $30 - $150 parts (switches/latch) + $120 - $250 labor (typical service call varies by region)

Replace shorted high-voltage capacitor and/or high-voltage diode

Estimated Cost: $25 - $90 parts + $150 - $300 labor

Replace magnetron (and inspect waveguide/thermal cutouts as needed)

Estimated Cost: $120 - $250 parts (often higher for OEM) + $180 - $400 labor

Replace high-voltage transformer

Estimated Cost: $120 - $300 parts + $200 - $450 labor

Replace turntable motor or cooling fan motor (if shorted/seized)

Estimated Cost: $30 - $120 parts + $120 - $250 labor

When to Call a Professional

Breaker trips immediately when pressing START even when the microwave is the only load on the circuit (strong indicator of internal short in the high-voltage section).
Breaker trips when opening/closing the door (likely door interlock/monitor switch issue that can create an intentional short condition).
You smell burning, see smoke, hear arcing/buzzing, or notice scorch marks inside or around the outlet/plug.
The unit trips a GFCI/AFCI repeatedly and also trips a standard breaker on another circuit (suggesting an internal fault rather than nuisance tripping).
You would need to remove the microwave cabinet—high-voltage components can retain lethal charge even when unplugged.

Preventive Maintenance

  • Close the door gently and keep the latch area clean (avoid slamming the door, which can misalign or damage interlock switches).: Premature door interlock/monitor switch failure leading to breaker trips.
    Frequency: ongoing
  • Use the microwave on a dedicated circuit where possible and avoid running other high-wattage appliances on the same circuit.: Overload-related breaker trips and nuisance tripping.
    Frequency: ongoing
  • Periodically inspect the outlet and plug for looseness or heat discoloration.: Outlet overheating and electrical faults that can cause breaker trips.
    Frequency: every 6-12 months

Frequently Asked Questions

Why is my Kenmore Microwave tripping breaker?
Common causes include a faulty door interlock switch, shorted high-voltage components, or circuit overload.
How do I fix Kenmore Microwave tripping breaker myself?
Unplug the microwave, reset the breaker, and perform a controlled test to identify the issue.
How much does it cost to fix tripping breaker?
Repair costs range from $30 to $450, depending on the faulty component and service needed.
When should I call a technician for tripping breaker?
If DIY solutions don't work or if you're unsure about handling electrical components, call a technician immediately.

Community Analytical Insights

Analysis based on real user discussions from appliance repair communities

Can I Fix This Myself?

50%
DIY Success Rate Difficulty: Either

Common Issues Reported by Users

  • Faulty door switches (2 mentions)
  • Inverter issues (1 mentions)

User Suggested Solutions

  1. Unplugging the monitoring switch

    Success rate: 50.0%
Analysis based on 2 community discussions
View Sources

Data compiled from real discussions on r/appliancerepair and r/Appliances:

  1. Microwave breaker tripping
  2. Microwave keeps tripping breaker? Is it the microwave?

Community Discussions

Microwave keeps tripping breaker

Unplugging the monitoring switch stopped the breaker from tripping.

DIY View on Reddit →

Source: Reddit r/appliancerepair

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