As well as switchon surges there are bulb blowing surges, which can also pop RCDs. The momentary high current amplifies the less than perfect current balancing of real world RCDs plus cable capacitance has an unequal effect on current flow, since the L-E capacitance is across 0-330v while N-E is across close to zero voltage. NT 09:06, 26 May 2007 (BST)
Yup, there is lots more to go in the trip section. Personally I have never experienced bulbs taking out the RCD (MCBs certainly, and even rewireable fuses on occasion), but I expect this is far more likely on an already sensitised device. I must do some sums on stray capacitances dotted about, and see exactly how much influence they can actually make, before going overboard on these topics - I expect for most users of the article, the section on "tell me how to find and fix the problem" is going to be the most useful.
--John Rumm 16:25, 26 May 2007 (BST)