Newsgroups: rec.arts.theatre.stagecraft
Subject: Re: Basic wiring question
References: <[email protected]> <[email protected]> <[email protected]> <[email protected]> <[email protected]> 
Duncanwood  writes:

> On Mon, 31 Oct 2005 19:13:02 -0000, Frank Wood  wrote:
> >>     Safety requirement.  IF you have a burned out bulb that you are
> >> changing, and the power switch is on.    When you unscrew it,
> >> the outer shell of the bulb is easily touched by the fingers, while it
> >> is energized by the hot wire.   *ZZZZAP!*
> > Well, replacing a bulb with the power on is double stupid.Anyone but a
> > born, bloody, fool will disconnect the lentern Not just safety, Common
> > sense.
> But only a fool would attach live to the outer contact, you can't
> protect  against an infinite number of fools but the more that are
> needed to make  it go wrong the better.


Power on the outer contact is what happens in very many countries 
throughout Europe. Many lighting instruments that you plug to the 
wall outlet have plugs that you can plug to both way to the outlet, 
examples of such plugs are ungrounde flat "euro" plug and grounded 
SCHUKO plug. This "euro" plug plugs to most electrical outlets 
throughout Europe. SCHUKO is used for example in Finland, Sweden, 
Norway, Germany etc.. 

When you have case where you can plug the mains plug on two 
ways to mains outlet, you never know if there is live or 
neutral on the outer shell of the bulb... 
And then there are also those countries where the outlet has 
two live wires with 230V between them and no neutral at all....


-- 
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at 
http://www.epanorama.net/