Newsgroups: rec.arts.theatre.stagecraft
Subject: Re: Flash Bangs etc/Le Maitre
References: <[email protected]>
	<[email protected]> <[email protected]>
From: Tomi Holger Engdahl 
Date: 09 Jun 1999 01:34:21 +0300
Message-ID: 
Organization: Helsinki University of Technology, Finland
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Chris Higham  writes:

> On those lines has anyone had experience of thr Le Maitre bubble
> machine?  We have one and I think it is the most unsafe product ever
...
> tray at the front that contains the mixture.  If the unit is knocked
> bubble liquid spills over the tray (even if it is only filled to the
> line) and runs back, straight to the motor.  Electrical sparks ensued
... 
> The whole thing is made of metal and I would think that anyone touching
> it before the mains tripped would have got a nasty shock, even though it
> was earthed.

The grouding in the metal case should make sure that the one
who touches the case will not be baddly shocked wven in case of
short circuit inside the equipment. If there is a short circuit,
the curretn will go tho ground though ground wire. If the ground
wiring is OK, then in the worst case (full short circuit from
phase to case) would be a half of mains voltage on the case
for brief period of time before the mains fuse or other protection
equipment cuts the power. 

Anyway anu equipment with electricity and liquids inside the same
equipment is potentiallu dangerous. In entertainment industry
at least those bubble machines and foggers fall into this category.
They should be at least well grounded and handled carefully to
keep them safe. Use of residual current breaker with those is a good idea.

-- 
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web pages at http://www.hut.fi/Misc/Electronics/