> >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.
First, to get common names:
Hot = one Phase
Neutral = Protective Ground
Ground = Ground (the starpoint on 3 phases connected to earth at the 'generator')
Hot and Ground are the basic wires to tap power,
Second, do I understand that US apliences got fuses on both wires
and both are switched ? Over here in Germany only one wire is
switched and protected with a fuse, althrough it is not defined
which one is the 'hot' line, since our connector is symetrical
- there is no way to insert the plug in a way where the Hot and
the Ground side is defined - Our plug isn't inherited from the
DC times, but rather a new design when 220V AC became standard
in the 30s, to fit the needs of (and only of) AC Eq.
Back in the 40s and 50s it was common to tie Protective Ground
an Ground within the outlet - especialy when they had converted
a DC householde (we had big DC networks in the 20s and 30s build,
and the conversation took place until the early 50s in some cities).
But for new insallations Protective Ground has to be 'real' ground,
in all cases, while it wasn't defined if one wire (on the outlet)
has to be a Ground wire and the other a Phase (hot) or if both are
Hot - this is irrelevant when it comes to AC. Even when there is a
'Ground' wire supported to a house (sometimes in the 50s and 60s,
houses where only connected to the power company via 1 phase AC
(unlike today where only 3 phases AC will be insalled) ) that
Ground was never defined to be a 'real' ground - so it might be
a 'hot' line in fact - but as said, in an AC environment it is
irrelevant (especialy when Protective Ground is provided).
> >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.
Often done that way over here, but only when ground is also
'grounded' at the house entrance - in fact, to go exactly by
the rules, Protective Ground has to be grounded seperatly from
Ground, each with an seperate anchor.
Gruss
H.
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HRK
Received on Tue Apr 20 1999 - 11:22:31 BST