Maggie's Farm

From The Ultimate Guide to Sets and Reps for Strength Training,  I think these are pretty good common-sense guidelines for the powerlifts, based on your goals. For powerlifts, however, I would not ever go over 10 reps per set. Instead, up the weight or the sets. Too many muscle twinges can happen with higher rep powerlifts, I believe. Higher reps for small or isolated muscles are fine, eg tricep push-downs, calf lifts, curls.

Exercisers need to know their max, approximately, for their powerlifts. For example, if I can deadlift 300 lbs for one or two reps, my 80% intensity is 240 lbs. What I do with powerlifts (not saying it's the best thing to do) is a warm-up set of 10 at 50%, then 4 working sets which gradually work up to about 80%. Just for fun, about once a month I will see if I can increase my max for 1 or 2 reps but I don't count that as a working set.