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Explaining tri-phasé please

Posted by guillygirl29 - Created: 3 years ago
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7 replies (Showing replies: 1 to 7)

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Posted by Yellowperill - 3 years ago

FGS 3 phase is just what it says on the labe 3 single phases that some appliances and be wired to run on all 3 phases usuall commercial or the larger appliance, 3 phase is a very efficient way of moving power around, in your domestic property chances are all your house wire ring will be single phase no different than UK single phase well not as far as it matters for this thread,  depending on the amount of your supply will determine you phase loading hence balancing the phases a very simple and easy task imagine everything you have that is electrical is turned on at the same time  split all those separate items circuits into 3 then each section is wired from the mains on a separate phase simple as that, 

Your incoming will be 3 lives each live is a single phase no big deal just keep each live separate         A domestic supply in the UK is usually 60amps for a domestic single phase supply not so in France your supply is by KW and will be up to what you sign up for and what your standing charge is set on in France the majority of domestic supplies in the country are 9Kw hence each single phase load is far less, you can only take up to a 1/3 of your overall supply per phase. Your best bet is to get a competent electrician rather than info from here and for info any UK electrician will know all about 3 phase same as the French do, good luck

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Posted by guillygirl29 - 3 years ago

Hello George , Thanks for your concern, maybe the wrong choice of word 'play', I mean't we would experiment with different appliances across the different floors to even out the puissance, it goes without saying that I would never play with electricity, especially French ! We have tri-phasé installed by EDF already just trying to fathom out how it all works together over the different levels, as I have been advised by others, we will have to experiment and put the ballons on timers. regards Ella

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Posted by georgeV-988991 - 3 years ago

Just a warning about 3 phase supplies.  Do not be tempted to play with the phases, you need a qualified electrician.  415 volts across the phases kills and if you avoid that fate you will almost certainly render many appliances useless.

I helped a family in the Vendee.  I was told that a French Electrician had changed the wiring and that nothing was working except some of the lights and the kettle.  The lady of the house let it slip that her husband had had his fingers in the box, not a French Electrician.  He had blown almost every appliance in the house and of course it wasn't covered by insurance.

If you can get the power into the house that you need on a single phase then that is the best answer as it gives full flexibility without the need for balancing and the fear that you will exceed the supply on one phase causing everything to shut down.  It all depends on what EDFcan supply.

If EDF cannot supply 75A on one phase then you have no option but to go for 3 phase.

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Posted by guillygirl29 - 3 years ago

Thank you for the replies, most helpful, I think timers for the ballons is a must and we will have to play with the appliances and the phases to see what works best and where, fingers crossed ......

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Posted by ingetje - 3 years ago

hi there, we have the same set up, 3 gites and our own house on 1 three phase meter (15KVA like yours  so 3 times 25amps). the balance is to make sure you od not have all the big things on one, but spread them over the three...so to say if you have 6 ballon for the water, then put 2 on each fase...and we installed mters on them and each one goes on at different times at night (heur creuse!) you also want to make sure that the heating is spread and same for the electric ovens, washing machines etc...and then each fase can have some lighting and sockets on them.

We never had a problem, so it does seem to work! be ready for a big bill, we pay around 250 a month, but that is 4 full houses with full kitchens and washing machines etc; rented out for about 30 weeks a year each.

good luck with your business!

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Posted by plouyepaul - 3 years ago

Hi Ella,

~The balancing he speaks of is between the 3 phases. Effectively you have 3 live wires supplying the house and a single neutral instead of the single live and neutral normally associated with residential supplies. Basically it is one way of providing your power requirements with out paying a larger standing charge, the higher your needs the higher the standing charge. 3 phase is more expensive than a standard supply but the power you need would be very expensive to provide because it is unusually high given your situation. The circuits used here are different, in the UK you have a Ring Main, often this would supply even a large house such as yours. In France the power is derived directly form the supply unit in a way we might describe as 'spurs' in the UK.

Given your power needs 3 phase is probably the best option inthe long term. Your electrician speaks of balancing the 3 phases to supply different areas of the house. For example all your lighting and small appliance outlets would probably be fine on a single or mono-phase but when it comes to water heaters, cookers fridges etc the load has to be estimated when everything is in use otherwise at some point fuses will start to blow/trip. If you have already fitted all your water heaters etc and indeed some of the other heavy use appliances especially electric radiators then you will probably be advised by EDF to go 3 phase (tri-phase). If you haven't already fitted your heating and water heating you might be in a better position to go with some other means of heating and water heating such as oil or gas, the problem then is the cost of installation. It's a matter of balancing what you need with what you can have according to the mighty EDF. If you are using electric heating I believe EDF can offer a sum of money towards optimising insulation, they as with most other power providers retty much worldwide are struggling to meet demand, power shortages are common in many parts of the world you would think it unlikely such as the USA. As with all things in life you pays your money.............. Hope this helps a little, it isn't something you're likely to have come across in normal daily life in the UK unless you were in an industrial setting, far etc.

The following is an extract form Wikipedia, a lot more in depth and probably not necessary to go into it in such detail:

'A current system (or voltage) is composed of three-phase currents (or voltages) sinusoidal same frequency of the sameamplitude, which are phase shifted from each other by a third of a revolution is 2π / 3 radians (or 120 degrees) in the ideal case . If the frequency is 50 Hz, then three phases are delayed with respect to the other of 1/150 second (6, 6 ms). When all three drivers are traversed by currents of the samerms value, the system is saidto be balanced.

In the case of the electric distribution network can be modeled by three source voltage sine same amplitude, for example 230 V effective in most European countries, having a phase angle of 120 ° therebetween. Conveniently the voltage of the three phases is constant and independent of load, only the current in each phase to be dependent on output power.

Due to the phase shift of 120 °, a network of which the effective voltage between phase and neutral is 230 V will be a voltage effective between phases.'

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Posted by camion - 3 years ago

So, you have 5 water ballons- if they are the usual 3kw each, then surely that is your 15kw used before you start with anything else, or have you timers?

Just trying to clear up one issue first.