Coolant ingress in motor connectors or power cables is a frequent cause of shorts that trigger this alarm.
Use a Megohmmeter to check the insulation resistance of the Z-axis motor windings. If it reads near zero, the motor has a short to ground and must be rewound or replaced. 3. Contaminated Power Cables Coolant and oil are the enemies of CNC electronics.
The FANUC 414 on Z-axis is rarely a CNC board failure. In over 70% of field cases, the root cause is a mechanical brake issue or a broken encoder cable due to axis flexing. Start there.
for 30 seconds, then restart.