Newsgroups: rec.arts.theatre.stagecraft
Subject: Re: Carnival Float Lighting
References: <01c350f4$a2e6e8b0$7551b80a@DAVID_LEE> <[email protected]>  <[email protected]>
David Duffy  writes:

> > On 23 Jul 2003 22:51:59 GMT, Frank Wood  wrote:
> >
> >>> Please explain how 'an equipotential zone' means something
> >>> different from
> >>> 'all tied to a single potential'?  You imply that I am wrong and then
> >>> repeat exactly the same information using different words!
> >>
> >>
> >> We're talking apples and oranges, here.
> >>
> >> It is normal, in the UK, that the neutral side of the supply is
> >> earthed at the
> >> sub-station, and that the supply company supplies an incoming earth
> >> connection.
> >> All exposed metalwork should be bonded to the latter. Taps, sinks, pipes,
> >> whatever. That is what an equipotential zone means. Anything you
> >> can touch is
> >> at the same potential as you are.
> >>
> >> Live and neutral are different. They carry the loads. While the
> >> difference
> >> between them is defined, their relationship to the earth wire is
> >> not. I have
> >> met installations where the neutral was 90V above earth.
> >>
> >>
> >> Frank Wood
> >> [email protected]
> 
> Duncan Wood wrote:
> > Depends on where you are. In the countryside it is not unknown to
> > bond Neutral & Earth at the premises.
> 
> That's how all Australian 240V systems are wired. A local earth bonded
> to the neutral right there in the switchboard. Only active and neutral
> come in from the street. If not for the RCD, you *could* pull lots of
> current between active and earth.
> David...

The same wiring practices are also used in Europe.

For example in Finland (the country where I live) the supplied mains 
power is 230V 50Hz. It supplied either as single phase 230V power 
(live and neutral wires) or three phase 230/400V power (three live 
wires, neutral wire, 400V between lives, 230V from live to neutral). 
The neutral is connected to house grunding (lots of bare metalwire on ground 
below/around house to get good ground connection) the main electrical panel 
or near it. 

I quess that similar wiring practices are used in many other countries 
in Europe. 

Some drawings in things I am talking about can be found at 
http://www.epanorama.net/documents/groundloop/electrical_wiring.html


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