Deby Posted February 21, 2005 Share Posted February 21, 2005 Perhaps I'm being simplistic - but is getting 2-phase from a 3-phase supply just a matter of joining together two pairs of the 380V phases with the neutral to get 2 x 240V ??Fergus The Pauper (hubbie of the duchess) Link to comment Share on other sites More sharing options...
Quillan Posted February 21, 2005 Share Posted February 21, 2005 WARNING - DONT TRY THIS IT WILL ALL GO BANG.The voltage is derived between phase and neutral. the voltage between phases should be around 440V so by joining two phases together it really will go bang.I know a bit about UK electrics but not much about the French system but 3 phase is 3 phase wherever you go. Perhaps it might be an idea to explain why you would want to do such a thing and was your thinking was or is? There are French qualified electricians you use this site so if you explain they may be able to tell you how to sort things out. Link to comment Share on other sites More sharing options...
Deby Posted February 21, 2005 Author Share Posted February 21, 2005 Thanks - no I won't be joining up wires just yet!The issue is that I need to rewire a BIG OLD place - no earth, procelain fuses, old-cracked wires, etc...I've read up on the new Normes on the subject and come up with all the circuits etc; everything's balanced, but as it's essentially domestic use, it's all 2-phase.Problem is that the supply is 3-phase; the previous owners had a business and needed this. I also need the power - currently rated at 18kVA - so I'm not getting EDF to change anything. A long time ago they gave me a degree in Electronic&Electrical Engineering, but I haven't really needed to put theory into practice - until now! I thought you could use the neutral with any of the 3 pases to get essentially 3 sources of 240v. As I say though, it's been a long time. I'll undoubtedly have to get a French electrician to "bless" the new wiring - required I believe if you sell a place now?Cheers,Fergus Link to comment Share on other sites More sharing options...
Anton Redman Posted February 21, 2005 Share Posted February 21, 2005 The difference between any pair of the Phases will be about 400 volts. Between any phase and neutral it will about 230 volts. The French sold adaptors which plug into 4 phase cooker sockets to allow the cooker to be plugged in but other things like normal electric kettles to be plugged in.I you have four cables to the main supply one of these should be neutral ( Not Earth) . Link to comment Share on other sites More sharing options...
Quillan Posted February 21, 2005 Share Posted February 21, 2005 Sorry. I understand now what you mean. Yes you can just use 2 of the 3 phases each on it's own circuit but it would create an imbalance which may result in you having to fit power factor correction capacitors else you could make the meter think you are using more electricity than you really are. You would be better off using all three phases really just remember that you need to keep about 2M between items on seperate phases (it's so you can't touch both phases at the same time and get a 440V shock). Link to comment Share on other sites More sharing options...
Guest CFrost Posted February 21, 2005 Share Posted February 21, 2005 Just to add that the supply power you quoted as being supplied (and required) is of course presently based on your 3 phase supply. Also I think you will find that all kWh meters read only the resistive part of the current. It matters not (to you) whether the overall load is inductive or capacitive. Link to comment Share on other sites More sharing options...
BJSLIV Posted February 21, 2005 Share Posted February 21, 2005 If you are going to completely modernise the installation, with no commercial heavy duty loads, wouldn't it be simpler to ask EdF , or whoever supplies your power, to transfer you to whatever strength monophase supply you need? Link to comment Share on other sites More sharing options...
Dave&Olive Posted February 21, 2005 Share Posted February 21, 2005 having dealt with electrics both industrial and domestic as my time as a fitter in a few factories in the uk and I have never heard of 2 phase or 4 phasenew one to me but here are a couple of links that may help youhttp://www.totalfrance.com/france/forum/viewtopic.php?t=187http://www.totalfrance.com/france/forum/viewtopic.php?t=192 dave Link to comment Share on other sites More sharing options...
Nick Trollope Posted February 22, 2005 Share Posted February 22, 2005 [quote]having dealt with electrics both industrial and domestic as my time as a fitter in a few factories in the uk and I have never heard of 2 phase or 4 phase new one to me but here are a couple of links ...[/quote]Which isn't surprising, as they don't exist...What I suspect everyone means is 2-wire (Phase & Neutral - ie. SINGLE pahse) or 4-wire (Ph1, Ph2, Ph3 & N - ie. 3-phase).A 3-phase supply is 3-off single phase supplies that share a common neutral. The entire distribution system is 3 phase (with the neutral "earthed" at the power station).The trend nowadays is for single phase supplies & EDF will convert you if a) you ask & b) they can (ie. if their wiring is up to it). In cabling terms, it follows that single phase wiring is cheaper than 3 phase wiring (slightly) certainly, single phase parts, such as trip switches are alot cheaper.In this day and age, and unless you are using industrial machines or catering equipment that is only available 3 phase, single phase is going to be "better". Link to comment Share on other sites More sharing options...
Dave&Olive Posted February 22, 2005 Share Posted February 22, 2005 Which isn't surprising, as they don't exist...Nick hiwe know yes but he has a degree and I am but a humble fitter dave Link to comment Share on other sites More sharing options...
Inquisitive Posted March 7, 2005 Share Posted March 7, 2005 I need to ring EDF and request that they up our supply to 3 phase, could any one give me the correct terminology pleaseThanks Claire Link to comment Share on other sites More sharing options...
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