E402
Enphase Surge Protection / MOV Clamp Event

Charger displays E402; app may show 'Overvoltage surge detected – surge protection active'.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Lightning-induced surge on supply, Utility switching transients, Degraded internal surge protection components, Incorrect or missing external surge protection

How to Fix / Troubleshooting

Safety: After a surge event, internal components may be weakened. Inspect before continued heavy use.

  • Check home for other issues: Look for clocks reset or other electronics affected, indicating a broader surge event.
  • Visual inspection: With power OFF, a technician should open the charger and inspect surge protection components (MOVs, surge modules) for discoloration or cracking.
  • External surge protection: Consider installing or verifying a whole-home surge protector at the main panel.
  • If E402 recurs: Replace the internal surge protection module or main board as recommended by Enphase service procedures.
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Repair Difficulty

Hard 4/5

Required Part

Enphase EV Charger Internal Surge Protection Components
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