E18
Schumacher Line Wiring / Polarity Error

Charger shows E18 and immediately stops when vehicle is connected; may indicate polarity or wiring issue.

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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

Reversed line and neutral on 120 V models, Miswired two-pole breaker, Shared neutral on multi-wire branch circuit, Incorrectly wired junction box feeding charger

How to Fix / Troubleshooting

Safety first: Turn OFF the breaker and do not use the charger until wiring is verified by a qualified electrician.

  • Verify breaker type: Ensure the Schumacher EV charger is on a dedicated, correctly sized two-pole breaker (for 240 V) or single-pole breaker (for 120 V models) as specified in the manual.
  • Check wiring diagram: Compare the actual wiring in the junction box and charger input to the wiring diagram in the Schumacher installation manual.
  • Correct polarity: On 120 V models, ensure hot and neutral are not reversed. On 240 V models, ensure both lines are hot and no neutral is incorrectly used as a hot.
  • Eliminate shared circuits: The EV charger must not share a neutral or be on a multi-wire branch circuit unless installed exactly per code.
  • After correction: Once wiring is corrected, power up the charger and confirm E18 is cleared.
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Repair Difficulty

Hard 4/5
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