Need to be a bit careful here! Could be several interpretations...

'régime de neutre' is indeed very often 'earthing arrangement' (or 'scheme', I think, too) HOWEVER, it CAN sometimes be in fact referring to the actual arrangement of the neutral itself (i.e. NOT specifically with respect to its earthing) --- this is specifically possible in 3-phase systems.

And that 'IT' --- I'm not sure which specific earthing arrangemtn this may be referring to (there are many, with different abbreviations in FR), but it is fairly likely that it does NOT mean 'IT' in the sense of 'Information Technology', and hence, it may be a FR acronym that needs to be translated.

Sorry, I'm too busy right now to do the research for you, but I just wanted to check in and raise a warning to be on your guard here...

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Note added at 5 hrs 58 mins (2005-05-05 21:40:23 GMT)
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Following on from CB\'s excellent reserach, I would surmise (but haven\'t confirmed) that IT = something like Impédant Terre (meaning that it is connected to earth via an impedance (resistancce)

I\'m not familiar with this particular system in the UK (if indeed it exists), so I can\'t give you the name, but I suggest you try Googling with ground + impedance or earth + impedance --- that will give you way too many hits to manage, but maybe by searching within them, you\'ll find something relevant. Or search on the French term, and see if you\'re lucky enough to find a bi-lingual site...?

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Note added at 5 hrs 58 mins (2005-05-05 21:40:49 GMT)
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Following on from CB\'s excellent reserach, I would surmise (but haven\'t confirmed) that IT = something like Impédant Terre (meaning that it is connected to earth via an impedance (resistancce)

I\'m not familiar with this particular system in the UK (if indeed it exists), so I can\'t give you the name, but I suggest you try Googling with ground + impedance or earth + impedance --- that will give you way too many hits to manage, but maybe by searching within them, you\'ll find something relevant. Or search on the French term, and see if you\'re lucky enough to find a bi-lingual site...?

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Note added at 6 hrs 5 mins (2005-05-05 21:47:57 GMT)
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Well, the first answer Google came up with seems to confirm what CB has said:

Technical Forum

... protections... Another way to see things... This second design, called TI (impedant earth) is used in a few countries, among them France. I ...

list.picbasic.com/forum/ messages/5058/5249.html?1044353302

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Note added at 6 hrs 16 mins (2005-05-05 21:58:21 GMT)
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Here\'s the relevant post from the above ref., which seems to explain things pretty well; do note, however, that I think the abbreviaition used here \'TI\' is NOT a \'proper\' translation as such, but rather, a conversion of the French acronym; I\'m not at all sure that there exists an equivalent abbreviation in English...

On Mon, 03 Feb 2003 10:06:19 +0000, John Lawton Electronics wrote on
Re: PICBASIC-L Transformerless power supply:


To make it simple, there are two main distribution ways one can handle the neutral conductor\'s configuration with regard to the earth:

- Neutral to ground connection

- Isolated neutral

The main difference between the two is that when there is an
accidental short between a phase and ground (or the metallic enclosure
of some equipment), different things happen:

In the first case there is a surge current and the protections
operate. We say they open for the \"first fault\". Such design is used
in Germany and the USA and many other countries.

In the second case, nothing happens, except that the shorted phase is
now at the potential of earth and the two other phases and also the
neutral conductor float at high alternating voltages. It would take a
second fault (e.g. a short between another phase and ground or a short between the neutral point and ground) for the protections to open.

In fact, conecting the neutral conductor to the earth as in the first
scheme is strictly equivalent to voluntarily creating a first fault,
and in either case only the second fault opens the protections...
Another way to see things...

This second design, called TI (impedant earth) is used in a few
countries, among them France. I shall add that since it takes two
faults for the protections to operate, it is compulsory to detect the
first fault, this is why a voltage detector (VigilOhm for instance) is used to permanently monitor the potential of the neutral conductor, which should remain close to the potential of earth at all times in the absence of a fault. If it does not, then there must be a short on one of the three phases and maintenance personnal is informed of the fact, usually by an alarm light.

Why this (apparently) strange system? Simply put it allows for a
better disponibility of the equipments, which is important in a
factory (I am thinking of a Ford factory close by): a fault detection
makes it easy to isolate the faulty equipment without stopping a whole workshop, while in the other system the whole line may have gone down.

The above description is very basic: in fact the TN system (neutral
direct to ground) has a few subdivisions (TNC, TNS) whose description
would lead us too far. Interested persons reading french can give a
look at http://perso.wanadoo.fr/grc/protegerregimedeneutre02.htm for
some drawings, and I suppose that equivalent documents in english are
available on the internet.

However it is utterly important to know the difference between the two
main systems because of safety concerns: when I export manufacturing
machines to the USA they are designed for the US distribution system.
If they are built with French equipment they have a huge isolation
margin as a consequence of our French distribution scheme that implies higher isolation levels in the internals of our national equipments (yet another good reason to buy french 8-).

Conversely, if I want to use German made equipment such as e.g.
SIEMENS CNCs and motor control gear, I have to provide isolation
transformers with grounded neutral conductors at the secondary winding because the german isolation voltages are not sufficient for our distribution system needs... But I can deliver german gear to the USA without a problem; and so on...

* soub-ic-line.fr
* soub-urf.com
* http://www.astrosurf.com/soubie
* Alimentation thermostatée à découpage AlAudine NT:
* http://www.astrosurf.com/soubie/alaudine.htm




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Note added at 6 hrs 20 mins (2005-05-05 22:02:37 GMT)
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Loadsa Googles on \"régime de neutre\" + impédant, e.g.

STNA - Revue technique 65 - MUTANT
... être alimenté depuis une source d\'énergie alternative standard au travers d\'un réseau électrique caractérisé par le régime de neutre IT ou impédant. ...

www.stna.aviation-civile.gouv.fr/actualites/revues/revue65/...

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Note added at 6 hrs 45 mins (2005-05-05 22:27:06 GMT)
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This very helpful PDF doc. tells you all about the meanings of the systems, but still in FR:

http://www.ac-grenoble.fr/ecole.entreprise/CRGE/ref/Docs/GT_...

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Note added at 6 hrs 46 mins (2005-05-05 22:28:52 GMT)
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\"isolated neutral\" seems to be a popular term, I think I\'d be inclined to keep the abbreviation IT [according to the Schneider PDF above, that is more correct that \'TI\'], and add the explanation \"isolated or high-impedance neutral earthing scheme\" as a note.

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Note added at 2508 jours (2012-03-17 16:10:24 GMT) Post-grading
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For 'régime de neutre', Eurolex gives 'neutral point treatment'