Accessory lighting

[Randomrunner12]

To anyone that can best answer this. What would the harm be in using an outdoor rated extension cord be when used with a relay and bus bar system to power aux traverse lights?

I have a blue sea 12+ 12- bus bar that is powered by an gauge red black wire from my battery. All relays will connect to here and get there power and be triggered by correct switches. My concern is running a 300 watt light bar in the rear of those don't harness they provide using 16ga wire.

 

[Kirwin]

Most extension cords are 16 ga wire. 300 Watts divided by 12 volts is 25 amps. That's too much current for 16 ga wire. If you use10 ga primary wire you an pull up to 30 amps.