Sizing Fuses and Breakers 101 - Fuses, Breakers, & Overcurrent Protection | Ep: 5/6
23 February 2025 · 12 min · 64K views
What this video covers
Sizing fuses and breakers for DC electrical systems requires balancing the device's amperage rating with the wire's maximum ampacity. The minimum fuse size must match the device's rated amperage, while the maximum size is determined by the American Boat and Yacht Council (ABYC) standard, which allows up to 150% of the wire's maximum ampacity.3:41 For a 100-amp device using 2-gauge wire with 105-degree Celsius insulation, the allowable fuse range is 100 to 315 amps.4:04 A practical rule of thumb is to multiply the device's amperage by 120% and round up to the next available fuse size, such as a 125-amp or 150-amp mega fuse.4:24 When using distribution systems like a Lynx distributor, each circuit requires individual calculations based on its specific load and wire gauge.5:27 AC circuit breaker sizing is simpler and dictated primarily by wire gauge: 14-gauge wire requires a 15-amp breaker, 12-gauge uses 20 amps, 10-gauge uses 30 amps, and 6-gauge uses 50 amps.10:05 Proper fuse sizing prevents fire risks while avoiding nuisance trips during normal operation.0:07
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