According to the NEC information that I found, 18AWG fixture wire has an allowable ampacity of 10 amps, and the allowable ampacity of 16AWG fixture wire is 13 amps.
Doing the voltage drop calculations, using the maximum allowable voltage drop of 3%, 110 volts supply voltage, and your load of 6 amps - the maximum length of the 18AWG fixture wire is 34'.? Any longer and you exceed the 3% allowable drop.? With 16AWG and the same conditions, the maximum length is 55'.
Don?
