heads up; OSI Challenger 1P

From: Daniel T. Burrows <danburrows_at_mindspring.com>
Date: Tue Apr 20 08:16:59 1999

>Please ? Equipment that assumes Neutral (protective ground) = Ground ?
>At least over here this kind of device is _strictly_ forbiddeen since
>>30 years, and I assume it's the same all over Europe. Only machinery
>with distinctive Ground and Neutral or with isolated interior is allowed
>(the wide variety of outlet/plug systems within Europe did support the
>later one a lot, since most are at least compatible for 'hot' and Ground
>pins :).


In all of the UK equipment that I service from one particular manufacturer
they only switch and fuse the one hot lead. The Neutral is "assumed to be
at / near ground so it need no protection. If this is wired to a standard
US residential then you will have no fuse protection on one lead. It will
also be floating when switched off waiting to bite you.
See the following attempt at ASCII art wiring which looks wrong if not
viewed fixed width.


US residendial 240 /120 mains power

   _______240V_________
   | |
  Hot____ Neutral_____Hot
   | | |
   |__120V___|__120V___|
             |
             |
             |
           Ground
 This is tied to Neutral
 at service entrance ONLY.


>standard voltage (with an upper limit of 120) which comes to 200V (208V),
>and not 220 - and 200 is definitive to low to drive 230V (240V) equippment.
>Not even the old standard 220V Eq will run properly in all cases.


This is where the US confuses people. In commercial 3 phase it is 120 phase
to neutral. 208 phase to phase.

Again with neutral tied to ground at the service entrance ONLY.
Received on Tue Apr 20 1999 - 08:16:59 BST