Microwave trips the household circuit breaker or blows a fuse when starting a cook cycle.

Critical safety warning: Repeatedly resetting a breaker on a shorting microwave is dangerous. Do not continue to use the unit until it is inspected.

User-level steps:

• 1. Try a different outlet/circuit: Plug the microwave into a different dedicated circuit (if available) to confirm the issue follows the microwave, not the circuit.
• 2. Remove other loads: Ensure no other high-wattage appliances share the same circuit.
• 3. Observe when it trips: Note whether the breaker trips immediately when pressing START or after a second or two. Immediate tripping often indicates a severe internal short.

Do not open the microwave or attempt internal repairs. Contact a qualified technician; likely components include the high-voltage capacitor, magnetron, or line filter.