Display shows 'NO GROUND' and charging will not start. Vehicle may show 'Charging Error' or 'Check power source'.

Safety first: Do not bypass the ground connection. A missing ground is a serious shock hazard. Turn off power at the breaker before opening the EVSE.

• Step 1 – Verify outlet or feed: If using a plug-in OpenEVSE, test the receptacle with a 3-light outlet tester or multimeter to confirm a proper ground. For hardwired units, have an electrician verify ground continuity from panel to EVSE.
• Step 2 – Inspect internal ground connection: With power OFF and cover removed, locate the green or bare ground wire from the supply. Ensure it is firmly attached to the ground terminal block or chassis ground lug. Tighten any loose screws.
• Step 3 – Check for corrosion: Look for rust or oxidation on the ground lug, especially in outdoor enclosures. Clean the contact surfaces and re-secure the ground wire.
• Step 4 – Confirm wiring polarity: Verify that line and neutral (if present) are on the correct terminals per the OpenEVSE wiring diagram. Miswiring can confuse the ground detection circuit.
• Step 5 – Board-level check: If the ground wiring is correct and verified with a meter, but the unit still reports NO GROUND, the ground sense circuit on the main board may be defective. Replace the OpenEVSE main control board.
• Step 6 – Professional help: If you are not comfortable verifying grounding with a multimeter, contact a licensed electrician to correct the supply wiring.