Therefore, the size cable you need depends on two things: how much current you need to carry and how long your cable runs need to be. Without getting into the math behind it, the reason for this is that a cable’s resistance increases as its diameter decreases or the length increases. Thicker wires can carry more current for longer distances. Wire Size Requirements: Determining Factors 14 AWG, which has a diameter of 1.62 mm, can only carry 15-20 amps the same distance. In the AWG system, the higher the number of the cable rating, the thinner the wire and, therefore, the less current it can carry.įor example, if you look at the chart below, you will see that 12 AWG, which has a diameter of 2.05 mm, can carry 20-25 amps up to 4 feet. The US standard for measuring wire gauges is the American Wire Gauge scale, or AWG for short. Wire gauge is the measurement of a wire’s diameter or thickness. There isn’t one correct answer to this question.īelow we will discuss how to figure out how much power your RV uses and how to use that information to select the proper cable size for your batteries. What size wire you need for your battery cabling depends on how much power your RV requires. As a result, your battery cable size will need to be rated for the highest current and ultimately the thickest. Since they come directly from the battery, they typically carry more current (measured in amps) than any other cables or wires in your RV. Cables coming directly from your battery are the main artery of your RV electrical system.

Ground wire size chart