Disposal powers on but immediately trips the RCD/GFCI or main breaker; LED flashes four times (if present).

Safety first: Turn off the breaker and unplug the unit if possible. Do not reset an RCD/GFCI repeatedly without finding the cause.

• Inspect for external leaks: Check around the McAlpine disposer body, sink flange, and discharge elbow for signs of water leakage. Dry any visible moisture.
• Check the power cord: Look for cuts, crushed sections, or melted insulation. Replace the cord set if any damage is found.
• Inspect lower housing: With power isolated, remove the lower cover and look for water inside the electrical compartment. If present, the internal seals or lower housing gasket have failed.
• Drying attempt (temporary): If only slight moisture is present, you may carefully dry the area with a cloth and allow the unit to air dry for 24 hours before retesting. Persistent tripping after drying indicates internal motor insulation failure.

Where water has entered the motor or windings, the unit is unsafe to use and the complete McAlpine disposal should be replaced.