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What makes marine grade wire special?

I was in the market for pain old 14 AWG wire for a project when I came across spools of wire being sold as "tinned marine grade wire". I was curious to know what made this wire "marine grade". From this page, it turns out, marine grade wire is

  1. 12% bigger for a given wire gauge. So 14G marine wire is thicker than regular 14G wire
  2. Each strand of the wire is finer and individually coated with tin, making it resistant to corrosion
  3. The insulation on the wire is oil, moisture and heat resistant.
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