Not necessarily about power requirements, but I recommend rethinking an electric smoker. We had one for about a year, and it just didn't do the trick. It was so well insulated that just sitting in the sun, turned off, it would reach nearly 170 degrees inside.
The smoke is created by the chips in a container on the heating element. If the heating element doesn't come on often enough, you don't get much smoke. The only time ours worked consistently was when it was cloudy, and below 50 degrees ambient temperature. We got rid of it and now use a propane smoker, and it is great.
Howard and Peggy
"Don't Panic"