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#138070 - 08/12/03 10:11 AM 3ph power distribution in France
Elect Offline
Junior Member

Registered: 08/12/03
Posts: 7
I am designing a system to go into a plant in France. The information I received wrt their power supply in the plant is 400vac 3ph with an ungrounded neutral. (I am assuming Y with the neutral connected to the ungrounded center tap)

Does this make sense or is their something lost in the translation?

Also wrt to conductor color, I assume this neutral conductor should be blue.

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#138071 - 08/12/03 11:29 AM Re: 3ph power distribution in France
C-H Offline

Member

Registered: 09/17/02
Posts: 1508
Loc: Stockholm, Sweden
Defintely 230/400Y, but "ungrounded" could mean both a TT system and a IT system. The former, which is the norm in France, has the neutral grounded at the transformer only and uses the soil as ground conductor. That is, the ground wire goes to an earth rod only. Requires an RCD/GFCI to work, but you shouldn't need to worry about that since it is on the incoming service.

If it is an IT system, it is a truly ungrounded system. Again, you will need an RCD, which again shouldn't be your problem. There is something you need to worry about and that is ensuring that your system can handle the higher fault voltage. In case of a fault somewhere (inside or outside your system), you can have 400V to ground in case of a second fault in your system. This will affect e.g. the selection of circuit breakers.

Although I find it unlikely that it is an IT (ungrounded) system, such are sometimes used in industries where you want to continue running equipment despite ground fault.

I recommend that you ask them if it is a TT, TN or IT system.

European conductor colours are being changed at the moment. If this isn't going in tomorrow, the best bet is the new colour code:

N - Light blue
PE - Green/Yellow
L1- Brown
L2- Black
L3- Grey

But if you use the old, no worry. It should be good until 2006.

[This message has been edited by C-H (edited 08-12-2003).]

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#138072 - 08/13/03 05:02 PM Re: 3ph power distribution in France
pauluk Offline
Member

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
Hi Elect, and welcome to ECN.

As C-H has said, I don't think you'll find any ungrounded IT public 230/400V supplies in France. It would probably only be an isolated system within a building, if this is indeed used.

According to our available references, the "old" (or current) French coding is:

Phase A: Black
Phase B: Red
Phase C: Brown
Neutral: Blue
Ground: Green/yellow

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#138073 - 08/14/03 06:27 AM Re: 3ph power distribution in France
Elect Offline
Junior Member

Registered: 08/12/03
Posts: 7
Gentlemen,

Thankyou for you input. Since my first post I have been able to confirm that the system within this facility is an IT system. (unearthed neutral)

Given this, we were planning on bringing the three phases and neutral into our system to provide 400v phase to phase and 230v phase to neutral.

Assuming that the 230v loads are somewhat balanced accross all 3 phases I would assume that the neutral would have to be protected since it is ungrounded and therefore considered a current carrying conductor. If fusing was used and in the unlikely event that the neutral fuse blew while the line fuses did not, you would effectively disconnect the neutral from your 230v loads placing in series across two 400v phases. (not good).

Given this I would assume that the proper way to protect this would be to use a 4 pole breaker to assure that all phases and neutral are disconnected when a trip condition occurs.

I have been searching for information regarding this but have been unable to find anything. Does anyone know how or where to verify my line of thinking.

Thanks.

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#138074 - 08/15/03 07:21 AM Re: 3ph power distribution in France
C-H Offline

Member

Registered: 09/17/02
Posts: 1508
Loc: Stockholm, Sweden
Your line of thinking is perfectly correct. As it happens, the French circuit breakers always break the neutral. (It's a good thing on TT systems too) Thus, French 3-ph circuit breakers are 4-pole.

From "grounded" and "color" I infer you are American, but it would have been a good idea include that in your profile.

Effectively, you will need to use IEC breakers rather than the conventional American style.

Standard general purpose breakers up to 63A (I think) fall within the IEC 60898 standard. As this is an industrial system, you may need something outside this or something more special. IEC 60947 would then be the appropriate type.

Try googling for IEC 60947 breaker and IEC 947 breaker (The 60- was added to the numbering recently) to find some info for Americans. Breakers are called MCB's in British English, so you should try that to find manufacturers. The trailing numbers with dashes are different standards for breakers, switches, disconnects and a dozen other things that interrupt the flow of electrons in one way or the other.

Have a look at GE Power Controls

Please be aware that whatever you design, it needs to have CE marking. I suspect that you are designing some kind of machinery, in which case the requirements not only apply to the electrical system but also to the machines as such. Things like warning signs, emergency stops and barriers to prevent the machine to cut of the workers hand and so on.

[This message has been edited by C-H (edited 08-15-2003).]

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#138075 - 08/15/03 02:13 PM Re: 3ph power distribution in France
Elect Offline
Junior Member

Registered: 08/12/03
Posts: 7
CH

Thanks again for your input. Since my post I have been able to confirm this as well. The only outstanding issue I have is regarding the RCD.

Is this something that is typically required at the main power distribution for the plant or is it necessary to provide this on each piece of equipment that is connect to the IT system? I guess I have the same issue with the PIM. Not sure where to find this info.

Thanks for the tips Re CE. I crossed that bridge some time ago just as it was becoming a requirement. At that time it was basically impossible to find CE designated components in North America. Thought it would be a good idea to order components from Siemen being a European based company and all. They had to import all the necessary component regardless as their offerings this side of the pond were NEMA only!

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#138076 - 08/15/03 02:21 PM Re: 3ph power distribution in France
pauluk Offline
Member

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
With the TT system common in Europe, there needs to be at least some degree of RCD at the service entrance to the building to provide ground-fault protection on all sub-feeders.

This being a separately derived IT system within a plant though, all bets are off, and I have no idea what the generally accepted French method would be for such a system.

Many small companies this side of the pond had trouble even finding somewhere to test for CE marking when it was introduced. While they are on about harmonization, it would have helped a great deal if the European groups had just agreed to accept UL/CSA certification as adequate.

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#138077 - 08/16/03 08:36 AM Re: 3ph power distribution in France
djk Offline
Member

Registered: 12/26/02
Posts: 1269
Loc: Ireland
If I were you I would contact an electrical contractor in France who deals with industrial installations.

French regulations are very tight and quite heavily inforced. Failure to comply with what might be considered health and safety issues won't just get you fined / sued it could land you in jail if someone were to be injured.

You should really get the equipment inspected and if possible signed off by a local expert to remove any legal risk!

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#138078 - 08/16/03 08:40 AM Re: 3ph power distribution in France
djk Offline
Member

Registered: 12/26/02
Posts: 1269
Loc: Ireland
Paul,

For various quite justifiable technical reasons as well as substantial differences in what is acceptable in North America and the EU, particularly under older DIN, BS, NF and Nordic/Benelux regulations UL and CSA wouldn't have cut it unfortunately.

Also CE marking was designed to be much wider ranging and extends to all sorts of products.

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#138079 - 08/17/03 04:30 AM Re: 3ph power distribution in France
pauluk Offline
Member

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
I realize that the "powers that be" over here would never be likely to accept UL/CSA certification.

My point is that so long as there is no other incompatibility between North American and European systems, if something is considered safe in the U.S.A., why should it not also be considered adequate in Europe?

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