Wire size in your walls is based on current expected to be drawn through them . Current is a function of power and voltage , if you reduce the voltage you increase the current . A 14 ga wire is rated for 1800 Watts continuously at 120 V IIRC . 1800 W divided by 120 V is 15 amps of current . If you reduce the voltage to 12 V , to get the same 1800 W of power your amperage will be 1800 W 12 V 150 amps . That ' s enough to melt a 14 ga wire and start a fire . To handle that current you will need 10 wire , which is about the size of your finger and weighs almost five times more per meter . There are good reasons why we went to AC for grid use instead of DC . <| sep |> Beautiful . I want to use the name Clark , but if I can ' t , Kal L . will do just fine . D