Originally Posted By: SuperDave456
And remember that all extension cords are not built the same!
A 100 watt heater will work with your cheap standard cord in a garage close to a outlet, but when you start talking about the extended use of 500-1000 watts that cheap 14 gauge stranded cord, and the vehicle is at the end of a 90' cord, it is going to be put to task.
Much like a generator, to push a significant amount of juice along a longer cord the higher quality cord the better.
6' from the outlet in your enclosed/attached garage I don't think it will matter.
By my calculations, with 90' of 14 gauge extension cord, the 1000 watt heater will still be outputting ~930 watts of heat.
1000 watt heater will draw about 8.3 amps at 120 volts
Voltage drop for 90' of 14 gauge with AC power is about 3.77 volts
Using Ohms law, the heater has a resistance of about 14.4 ohms.
With the new lower voltage of ~116.2 volts, and the resistance calculated above of 14.4 ohms, we can now calculate the new current draw of about 8 amps.
Using 116 volts, and 8 amps you get about 930watts of power that will be delivered.
Of course, the voltage drop lowers the current draw, which means the voltage drop won't be as much...so the power delivered should be slightly higher than what was calculated.
Heaters don't care about a little voltage drop like a power tool might...so don't worry too much about springing for a super fancy power cord for something like this.
IMHO of course!