Cast-it Admin wrote:
I need to change the flourescent light unit in the kitchen from 3ft to 4ft
tube size. I've bought the new fitting which says I must switch off the
electricity supply at the mains / fuse box before attempting to fit it.

Is this totally necessary? surely switching off at the light switch isolates
the connections from power

Of course it does...but what would you expect an instruction sheet for
a DIY-er to say -- the most conservative or the least?

If the switch is where you can see/control it and/or you're the only
one working, it's safe enough to use it. OTOH, if the switch is
somewhere remote and SWMBO is in the other room and reflexively turns
it on while coming into check on how you're getting on while you just
happen to be hanging on the the black an reaching down to grap a
wirenut and are in contact w/ the sink where it's laying at the
time...you get the picture.