wire-wright

Size a whole boat's DC panel at once: wire, fuse, which rule decided each circuit, and which inputs are still guesses.

The list below is a synthetic 12 V panel for a plausible cruising sailboat, not a real boat's. Change any cell and the sizing on that row updates. Lengths are round trip (source to device and back).

Circuit

Amps

Len (RT ft)

Max drop

Engine

Bundled

Insulation

Amps src

Length src

Status

Wire AWG

Fuse

Decided by

Flags

Remove

length:guess length:spec: The run is not measured on the boat yet. Measure it before you buy wire.
amps:guess: The load current is a guess. A nameplate rating is believable; a hope is not.
planned: Not installed yet.

Just one circuit?

Circuit Current (A) Round-trip length (ft) System voltage Critical circuit (3% drop, not 10%) Passes through an engine space Bundled conductors

Wire size

—

Fuse

—

Same math as npx wire-wright, from the ABYC E-11 tables in the ampacity data package (republished with ABYC's permission at boathowto.com). DC, copper only, AWG 18 – 4/0. Sizing is per circuit: it does not sum loads or check fuse interrupt ratings. To run your own list, use the command-line tool.