On my P36 cutter, behind my electric panel, I have a busbar with five- 14 Gage green wires. Does anyone have these green wires and what are they? It is impossible to trace them without taking the whole boat apart.
Green wires are grounds. (generally) Certainly Pearson used that color code for their wiring. So that is a ground bus bar. What they run to..... Your guess is as good as anyone's?
theyre about the bonding system
all of the metal parts on the hull, like through hulls, the chain plates, shrouds and attachments, the engine and transmission are joined by green coloured wires. My own goes to a bus bar in the forward end of the port sail locker, which then goes back down the a copper ground plate on the outside of the hull roughly 18" by 6", I think it was fitted for now defunct LORAN
Basically the system is about reducing the effects of stray currents by equalising voltage potentials. It doesnt prevent electrolysis but it will help reduce it. I hear it also reduces RF for the electronics and the radio system as well
Theres a PDF out there that might help resolve for you what the bonding system does
http://www.svsoggypaws.com/files/MarineGrounding-StanHoney.pdf
image from the Pearson 365 Owners Manual