The only time that would be acceptable is if the power cord was rated equal or heavier than the load being pulled. A 1000 watt light pulls approx 9 amps. That's a strong pull for a single bulb. When the bulb first fires up, it'll draw more than that. To be safe, I'd have to recommend at a minimum, 14 awg extension cord, no longer than 25' or a 12 awg running no further than 40-45'
as long as you are not using a cheap 16 or 18 gauge extension cord, you should be alright.