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How to identify GROUND LEAKS on your BOAT! | Ask The Expert with NIGEL CALDER
June 13, 2026 · 2 min · 2K views
Nigel Calder tests boat electrical system with clamp meter.
What this video covers
Nigel Calder explains how to detect AC and DC ground leaks on a boat in a short Q&A with host Jan Attenstedt. For AC systems connected to shore power, clamping the shore power cord with a sensitive AC clamp meter reveals any leak current finding a path back to the dock through the water — a reading in milliamps or higher indicates a fault.▶ 0:39 DC ground leaks are harder to isolate systematically; the diagnostic principle is identifying disparities between the positive and negative sides of a circuit, which signal that fault current is returning to the battery through an unintended path rather than through the boat's wiring.▶ 1:17 Calder points to the negative side of the DC system as the critical factor: a continuous, low-resistance path back to battery negative leaves no alternative route for stray current.▶ 2:33 Grounded metal objects aboard create those alternative paths, and they become a problem only when the negative wiring has weaknesses.▶ 2:20 Correct wiring from the outset is the primary prevention.▶ 0:00
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