"paul wood" wrote in message
m...
Have just wired in two 58W fluorescent striplights to sit under
decking & it looks pretty good, when it works. Problem is, sometimes
when I switch on, the main trip on fusebox goes off. The two PIR
floods I wired in at the same time work fine. Can't find any fault
with my wiring! The lights are connected to a ring main via a switched
FCU. Any ideas, please??

What do you mean by 'main trip'? Is it the MCB serving that circuit or
something like an RCD main switch, protecting several circuits?

If it is only an MCB, it could be the start-up surge from switching on the
fluorescents. Experience suggests that switching more than about 70W at a
time can produce intermittent tripping of a standard 6 amp MCB. Your options
are to uprate the MCB to at least 10A (if the cable is suitable for this
current), to fit a type C / type 3 MCB, or to fit separate switches to the
lights and turn them on one at a time. The last is probably the easiest and
cheapest option.

Colin Bignell