Tinned copper is primarily used for protection against oxidation and corrosion. In climates where copper has long-term exposure to water, the oxygen will combine with the metal and form copper oxide, weakening the bonds of the metal.
Our Wire is Available in Spools or by the Foot
ABYC does not mandate the use of tinned wire in its standards, but tinned wire is more corrosion resistant.
Also see ABYC Marine Wiring Guide