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In my interpretation (#14) I have assumed a 3 wire 3 phase system without a neutral - 3 lines used for distribution, 240V between lines. Also poor ground conditions for the flow of earth currents hence my use of the term 'local star point' and the implied consequence of relatively high impedance between local and transformer earths.

I could well be wrong - but it came from a comment in an IET forum on how the 120V was upgraded to 240V in rural areas. ( see mdhamish at IET Forums - Wiring in Spain - http://www.------.org/forums/forum/messageview.cfm?catid=205&threadid=6282)

I could not find much information on Spain's LV network other than Schneider saying Spain has 400V using 3 and 4 wire distribution.

Perhaps the OP can look out the window and tell us how many conductors he sees on any poles carrying the current to homes?

As you say - enough speculation. :)
 
I have assumed a 3 wire 3 phase system without a neutral
The problem with that assumption is that, on a 3-phase delta system, there shouldn't be anything as high as 345V present anywhere, even with any combination of faults (barring freaky scenarios such as both a lost reference and someone having a large step-up autotransformer with a fault on the output pushing the whole distribution system off centre). The highest voltage that can be expected to appear with a combination of faults would be if the two lines other than the OP's line were leaking with equal impedance to E, and his line was not leaking at all. That would put the E midway along the vector between those two lines, creating an L-E voltage of *not what I just said, hang on..* f the readings are correct, I maintain that by far the most likely configuration is a 240/415V 3-phase 4-wire system.
 
As you point I have made a blunder. One would need a 4 wire star system 240/415V and not a 4 wire star 140/240V nor 3 wire delta 240V to obtain 345V L-E.

:)
 
And I too made the error of adding the phasors, expecting a voltage between 240 & 415, out of sheer force of habit, which I got. Of course the voltage in that situation would be sqrt((240)²-(240/2)²)=207V.
 
Apologies just for confirmation. All I saw was " the readings are correct".

Assuming my feed is 2 conductors from the 4 wires is that the case?

I'll go into my field tomorrow as the supply line passes through it and see if I an tell how many conductors there are.

I won't be cancelling the electrician either way as I want him to confirm everything is OK from my side before I call FENOSA.

I would like to have an understanding of what system I may have so I can prepare the Spanish words and understand what he tells me with regards to the supply.

Thank you
 
Potencia, retorno, tierra...
all you need to know. My experience of Spanish electricians is all good. OK, some existing (and some new) installations are just carp, but I have found that bringing an electrician in is just such good value and well worth it. They are well used to the old junk, and quite clued in to the newer ways...indeed, my CU has had to be updated twice in the last 10 years...I'm just waiting for Endesa to tell me I need a metal one! And don't forget, they do a good job at €17/hour...
I first-fix at 12...includes a pie and a beer at 9am on a 20 minute break for breakfast...in the sun! Perfect!
 

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