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
Ron
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!!!
Ron
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.
Hi
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
Ron
Because resetting all the damned digital clocks is worse than death, for some people. :-)
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!!!!
Ron
...
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 beginning work.
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.
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.
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?)
--Goedjn
The light almost assuredly is a different breaker than clocks.
Bob
The person involved it likely to have not previously identified the breakers, and will have to turn several others off too.
I saw some "WARNING: WATER ON ROAD" signs this summer. Those looked like jokes, considering how dry it's been here.
Probably not electrocuted. Maybe a broken back when you fall off the ladder find out how hard that floor really is.
This is England with 240 volt power. If you get knocked on your ass and come to in the emergency ward, you will know you should have turned off the breaker ;)
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 ( snipped-for-privacy@misty.com)
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