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.
turn breaker off for CERTAIN!
some bozo may be switching the neutral wire leaving you exposed to a
nasty shock, some of the wires in the top of the box may be hot even
with the light switch off.
why work unsafely when safely is just a breaker trip away?
Yes thanks I thought I wasn't going mad. The leaflet actually over
emphasises the need to switch off at the mains - it's the only bit printed
in red bold underlined type - I suppose Tony Blair got one of his nannies to
write it :-)
The switch is about 4ft from the unit and I would tape something over it -
just in case!!!
This is best answered by someone in the UK rather than the USA. UK wiring
is a bit different than ours. How sure of the wiring are you? If the
switch only breaks one pole, the other would still be live and a potential
shock. Do you know how to test it? Is it a double pole switch?
If you feel a tingle in your body, you will then know the correct answer it
to turn off the breaker.
No I don't know how to test, I guess I'm being lazy, our main fuse box isn't
a breaker type it is fuses in blocks and I just didn't want to have to
switch off the mains and reset all the house clocks, video's security camera
recorder and completely reset my mutli sat satellite receiver which always
seems to loose it's memory when disconnected from the mains - all for a job
which should take more than ten minutes
I'm told with the old fuse type fuse boxes you can't just pull a fuse block
out you have to switch off remove the block and then switch on again which,
in this case , would defeat te objective
Some of those devices may NOT lose their settings if they're only
disconnected for a short time. For example, my Sony VCR is good for an hour
or two, according to the manual. Run an extension cord to the devices, from
a different circuit. Move their plugs quickly, and maybe you'll get lucky.
Nah not mine, we had a 1 min power cut just days ago and boy does it f*** up
my security camera hard disk recorder! I had to reformat the damn drive tehn
go through the unnecessarily long set up process - why manufactures torture
us like this I don't know!!!!
Ahhh....I failed to notice where you posted from and wasn't thinking of
outside US, sorry -- I'm not positive whether double-pole switches are
required. If not, being as you use 220/240, you still would have a hot
side, so that would be a real reason for the recommendation/warning.
And, of course, as someone else pointed out, even in the US there's
always the possibility of a miswired switch that breaks the neutral
instead of the hot so it's still only prudent to check before actually
You can check after you turn off the switch by taking an incandescent
bulb on pigtails across the leads if you don't have a voltmeter. Check
each lead to ground and if there's still a hot lead, the bulb will
light. It won't be full brightness if rated for 240, of course, but it
will be enough to show you still have power.
Not so. There are legal ways to wire a light/switch combination such
that the light being off does not guarantee no power in the box.
(and that assumes that the last guy followed the rules.
But YOU'RE not going to, so why should you assume he did?)
Like this? Maybe it won't be so "reflexively"?
There once was a man from Woonsocket,
Who stuck his left thumb in a socket.
His wife was a bitch,
And flipped on the switch,
Which made him take off like a rocket.
Jeff (Who just cleaned that lim up a bit for family consumption....)
Classic Far Side cartoon:
Picture Vikings storming the castle walls: Arrows, boiling oil, spears,
stones, everything. On the top rung of the Viking's ladder: "NOT A STEP"
And, if you ever do buy a step-ladder, it will come with a four-page booklet
of do-nots. (Do not use underwater, while carrying burning rags, eating,
while under the influence of drugs, in a moving vehicle, etc.)
Somewhere online about a year ago, I saw a picture of a real label from a
jar of peanuts, with the line "Allergy information: Produced in a facility
which processes peanuts". I hoped it was someone's idea of a joke.
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