Thanks for the info Keith, Preheat may be an option, but the problem is more prevalent when setting up, using the remote focus unit you tend to turn a lantern on full, focus it, move onto the next one. If the dimmers are set to preheat every time they are switched on (i.e. any time anybody is working on the lighting rig / desk) then you could be looking at 20 hours a week in power consumption at 5% is like having the whole rig on for an hour at a time. Having chatted to a few people, they were wondering whether the type of MCCB chosen was causing the problem. I'm no electrical expert but they were talking about type B, C and D fault curves. Any further advice would be appreciated, because I would hate to find out we were specified the wrong type (or max load capacity) of dimmers for our theatre