I was at a safety class last year and this same discussion came up. I haven't found anything in writing to answer the question, however I think this is a case where common sense should prevail. As I was taught (by two old guys who had all their fingers and minimal scar tissue) generally stand to the hinge side of the enclosure door, it has the most hardware and in the event of a blast the idea is the door will take the brunt of the blast and may help push you out of the way. The opening side, either bolted or latched, generally had less hardware, and in the case of bolted doors, how many do you run across in service that all the holes and hardware are in good shape? I have taken safety briefing from SCE and PG&E and both generally go the way of working from the hinge side.
Zog's idea is the best, but not always available. So an overall procedure of knowing overall equipment condition, is there a risk (say new or well maintained equipment versus old or in not so good of shape), and proper PPE and other safety procedures is the best bet. I always tell junior people I work with to work from the hinge side as a matter of practise because that is how I was taught and to date has served me well.
Of course if you have disposable people Gunner's idea is pretty good too.
Hope that helps, Mike L.
