I'm about to order some transformers for LV downlighters. I note that
S'fix do a 'self-monitoring' model (52120) for about twice the price of
a standard one (48058). This function apparently allows me, the user,
"to determine the operating state". What on earth does that mean??!!
Worth having?

Thanks
David

ref 52120:
http://www.screwfix.com/app/sfd/cat/...12 0&ts=33800

ref 48058:
http://www.screwfix.com/app/sfd/sea/...1&cd=1&x=0&y=0