When designing/installing any electrical circuit, there are many things to take into account. The size of the conductor needed in the system is critical. Undersized conductors create increased resistance resulting in heat and voltage drop. When sizing cables, we refer to the ABYC tables for voltage drop. ABYC provides two tables: One table provides cable size for a system in which a 10% voltage drop is acceptable; the second when a 3% voltage drop is acceptable. On a boat, it is prudent to use the 3% voltage drop table due to the extreme conditions of a marine environment. ABYC E-11 Table IX shows the accepted wire size for a 3% voltage drop. When sizing wires with this chart, it is important to remember that the length of the conductor in the chart refers to the entire length of the circuit: both positive and negative. The chart also needs the total number of amps being used in the circuit. If for instance you have five 12 volt lights in a circuit at 1 amp each, you would use 5 amps as your total current, in amps, on the chart. This is just one of the many considerations that need to be made when designing a sound electrical system. Stay connected!