In article , 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

If you want to bet your life that the switch is actually in the hot leg
where it belongs, and no damn fool will turn the switch on. Even if you
don't get electrocuted, a shock can jolt into falling, dropping something
or hitting your head and/or hands into something or any combination of
these.

My dad says - when you turn off the breaker, unscrew the wire and put
the breaker in your pocket.

- Don Klipstein )