If your AC trips the MCB (miniature circuit breaker) every time you turn it on, it indicates an electrical issue that needs immediate attention. Never force the MCB back on repeatedly as it can cause electrical fires. Here are the 6 most common causes and solutions.
6 Causes of AC Tripping MCB
1. Compressor Issue (Most Common)
A faulty compressor can draw excessive current, causing the MCB to trip. This is especially common in older ACs (5+ years).
Symptoms: MCB trips when compressor starts, humming sound before tripping.
Fix: Professional compressor diagnosis and repair/replacement. Home Fixer provides same-day compressor repair.
2. Capacitor Failure
A weak or failed capacitor can't provide the starting boost needed by the compressor, causing it to draw excessive current.
Symptoms: AC struggles to start, clicking sound, MCB trips on startup.
Fix: Capacitor testing and replacement. This is a relatively inexpensive repair.
3. Short Circuit in Wiring
Damaged wiring within the AC unit or between indoor/outdoor units can cause a short circuit.
Symptoms: MCB trips immediately when AC is turned on, burning smell.
Fix: Professional wiring inspection and repair. Turn off the AC immediately if you smell burning.
4. Ground Fault
Water leakage onto electrical components can cause ground fault, tripping the MCB.
Symptoms: MCB trips, visible water near AC, GFCI outlet trips.
Fix: Fix water leakage first, then inspect and repair electrical components.
5. Incorrect MCB Rating
The MCB may be underrated for the AC's current draw. A 1.5-ton AC needs at least a 20A MCB.
Symptoms: MCB trips when AC is running on high load or when other appliances are also running.
Fix: Upgrade to a higher-rated MCB by a qualified electrician.
6. PCB Board Issue
A damaged PCB board can cause short circuits or excessive current draw.
Symptoms: Intermittent tripping, AC behaves erratically.
Fix: PCB diagnosis and repair/replacement by Home Fixer technicians.
