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How to HOOK UP and FUSE your SOLAR CABLES! | Ask The Expert with NIGEL CALDER
23 August 2025 · 3 min · 5K views
What this video covers
Nigel Calder explains where to connect MPPT charge controller output and, critically, how to fuse solar wiring correctly on multi-panel installations. The output should run to the batteries — via a positive and negative busbar near the battery bank — never to the alternator output terminals.▶ 0:52 On single-panel or series-connected systems, fusing is straightforward: one fuse rated to the conductor's ampacity.▶ 1:12 On catamarans and other multi-panel setups, individual panels feed separate controllers that converge on a common busbar, which then runs a larger feeder conductor back to the batteries.▶ 1:27 That feeder carries aggregate current and requires a larger conductor, but a fuse sized only to that feeder is grossly overrated for the smaller individual conductors branching off to each controller.▶ 1:36 Those smaller conductors must each carry their own fuse — an automotive fuse block is a compact solution.▶ 2:24 Calder cites a real boat fire where the main feeder fuse failed to protect undersized branch conductors.▶ 2:15 No fuse is needed between a controller and its panel if conductor size does not change.▶ 2:35 A free wire-size calculator and a BoatElectrics 101 course are available at BoatHowTo.com.▶ 2:54
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