Robot lawnmower does not detect the boundary wire and attempts to leave the mowing area; display shows E02 Boundary Error.

Safety first: Turn OFF the mower using the main switch and remove it from the lawn. Disconnect power to the NAC charging station before handling wires.

• Check charging station LED: Most NAC bases have a status LED. Refer to your manual: a solid green usually means the loop is OK; flashing or off indicates a loop fault.
• Inspect boundary wire at base: Verify both boundary wire ends are firmly clamped into the charging station terminals. Tighten screws and ensure bare copper is making good contact.
• Walk the perimeter: Follow the boundary wire around the garden. Look for visible cuts from gardening tools, pet damage, or pulled‑out pegs. Repair breaks using NAC‑compatible waterproof boundary wire connectors.
• Test continuity (advanced): With a multimeter set to resistance, disconnect both wire ends from the base and measure between them. A very high or infinite reading indicates a break in the loop.
• Check splices: Any previous repairs or joins are common failure points. Re‑crimp or replace with gel‑filled waterproof connectors.
• Restart system: Reconnect the loop to the charging station, restore power, and confirm the base LED shows normal operation. Then power ON the mower and test. If E02 persists and the loop is intact, the boundary transmitter module in the charging station may be defective.

Warning: Only use low‑voltage boundary wire and original‑type connectors. Do not connect the loop to mains power.