A pal has a light fitting comprising 15 20 watt 12 volt lamps. Fed from a pretty massive toroidal transformer in the base. After having had a new consumer unit fitted, it tripped the MCB. Every time. It's on a 6 amp lighting circuit.
The sparks who installed the new CU doesn't want to know - he was sort of supplied by the people who fitted a new bathroom with some form of whirlpool bath - and they insisted it had to be upgraded. I've a feeling they also installed/split the lighting load into two - it's a small house and originally only had one circuit. My pal is a bit vague about such things.;-) The fitting has been replaced by a single bulb pendant which works ok. Other clue was the wall switch sparked when this fitting was switched on.
My guess is the inrush current is simply too great for a standard MCB. I have the fitting to check out - but no bulbs with it as yet, as he couldn't find them.
Anyone have an idea what the peak current demand would be this sort of arrangement? I could obviously just fit a type C MCB - but am curious about the sparking light switch too.
There's plenty of room in the base for two or more electronic transformers - but altering the wiring inside the fitting to split the load might not be so easy.