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3 Phase Electrics - help
by glenncaton • Fri 25 Jan 2008 18:55

I have bought a house which has 3 phase electrics fitted, I think this was mainly for the outbuildings . I need to re wire the place,but can only do it a room at a time .I believe that the house might be utilising just one of the 3 phases (if that is possible) and I wondered if anyone had any diagrams/advice as to the most appropriate way forward. I am about to ask EDF to re connect the electricity and would appreciate any advice as to what I should be asking them to do at this stage. I am keen to revert back to single phase, but am not sure if the existing house elctrics will work if I do while I am in the process of re wiring. Regards

glenncaton
3
Jan 2008
Re: 3 Phase Electrics - help
by Goose • Sat 26 Jan 2008 10:20

Ask EDF to reconnect as single phase, its free and should not be a problem for the existing wiring. The onle problem that we had when this was done was that the electric water heater was wired up three phase and had to be changed back to single phase to work. I would strongly suggest that if you are not sure how to do French electrics you consult a registered artisan, the system is very different to the UK.

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Goose
350
Mar 2005
Re: 3 Phase Electrics - help
by tazgully • Mon 17 Mar 2008 19:41

Hi,
If you have an old meter it should say whether it is monophase or triphase and also it will have the voltage on it probably 220volts for monophase or 400volts for triphase.
PLEASE BEWARE A SHOCK FROM 400VOLTS TRIPHASE IS FATAL.
Good luck

tazgully

tazgully
2
Aug 2007
Re: 3 Phase Electrics - help
by RobertArthur • Mon 16 Mar 2009 14:48

Glenn,

Yes, it is possible they used only one phase for the electricity in the house. Have seen that several times. Just think of triphasé as 3 separate monophasé lines of 230 Volts with respect to neutral, the blue wire. Indeed there is a phase shift between these three, resulting in the dangerous 400 Volts between them (L1- L2, L1- L3 and L2 -L3).

In a reply early this morning to Garry (subject: electric meter) I 've included some links. The included diagram of the triphasé installation (last link) is useful for reference. The only thing you have to think away in picture # 1 is the main switch - disjoncteur de branchement, DB TRI - and replace it with its monophasé brother. And draw one thick phase line to the three interrupteurs différentiel. And forget the 3-phase boiler (chauffe-eau) in picture # 2.

Three-phase systems have one inconvenience: if you were to have a puissance souscrite of 45 Amps in total, this power is distributed over the 3 phases. Each of them protected by the main switch (disjoncteur de branchement) at a trip current of 15 Amps. It is very easy to overload one of these phases, and then the main switch comes in, cutting off all of your electricity. Even worse: a 3 x 10 Amps connection (30 Amps total, 6kVa). Balancing the three phases is difficult (distributing the loads as evenly as possible over the three phases), especially in the smaller private home environment. With a 45 Amps (9kVa) monophasé connection it takes a lot of more loading to trigger the 45 A treshold in the disjoncteur de branchement. My advice to everybody - not being the proud owner of heavy 3-phase equipment - is to change these low-power 3-phase connections in a single-phase connection. You get a lot more of "headroom" before the overload protection in the main switch comes into action. It even allows you sometimes to go back - even EDF consultants are willing to point this out to customers - from e.g. 12 kVa to 9 kVa, or sometimes from 9kVa tot 6 kVa. Taking a look at the EDF tariffs today, this implies you have to pay less for your annual abonnement option base or option heures pleines/creuses. But perhaps better, for your own peace of mind and lighting conditions at night, to spend the few euro's extra to have plenty of headroom. By the way, speaking about tariff options: EDF is phasing out the option tempo. Existing connections go on, but suspended with the arrival of a new owner or new tenant (changement de nom). On almost all EDF (regional) websites this option has been removed. The same goes for its older sibling, the option EJP.

As long as you are connected to the EDF power grid, and pay your bills, the change from triphasé to monophasé is something following standard procedures. But not for free: nowadays they charge a standard E 135 and some cents for this intervention. Not a state company any more, private firm, less free service. Only when you want more power, several steps up the ladder, e.g. from 9 kVa to 18kVa, they are going to ask technical questions (is your installation safe and designed for the extra Amps) and perhaps send in the marines, sorry, the Consuel. One step higher is allowed without additional control.

For a new connection (raccordement), a major renovation or substantial power upgrade, the plot thickens. Then you are always in for a visit of CONSUEL to check what you 've done. You better do it, every inch, in conformity with the French NF C 15-100 regulations. Even the French, used to more than their fair share of bureaucracy, start trembling a bit, once they set foot in a maison pour controler tout ca. Otherwise no green light, no EDF connection.

Kind regards,

Robert

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RobertArthur
280
Mar 2009
Re: 3 Phase Electrics - help
by RobertArthur • Fri 26 Nov 2010 20:56

Some time ago I wrote: "Balancing the three phases is difficult (distributing the loads as evenly as possible over the three phases), especially in the smaller private home environment". Having a lot of measurement tools, I forgot to mention a very simple way of measuring these loads, with equipment already provided by EDF: le compteur. The electronic Sagem, Siemens and Landis+Gyr meters have two little blue push buttons. The lower one called "defilement" (total consumption) and the other one "selection". With this button you get access to a little menu structure, see page 10 of this Sagem documentation. Under item 4 you'll get a digital read-out of your power consumption at that moment, for every phase. Either in watts, or amps, which ".... permet en particulier de mieux équilibrer les charges sur chacune des phases". And for those who want to "opt out", go to monophasé , change their tarif or puissance souscrite, on one of the ERDF websites there is an interesting page, title: Changer de puissance électrique. From there we go to their pricelist, Catalogue des prestations ERDF. On page 39, Fiche F 180, Modification de formule tarifiaire d'acheminement ou de puissance souscrite you'll find several quotations for services offered for domestic supplies (max 36 kVA).


Kind regards,


Robert

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RobertArthur
280
Mar 2009
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