"Pose en trèfle jointif" in French is "close trefoil formation" as per the GDT, so it seems reasonable to suppose "pose en trèfle" (and thus pozare în treflă) is "trefoil formation" (i.e. for a three-phase cable line):

"The following formula taken from the Cenelec standard for cable cleats EN 50368 calculates the force experienced by a cleat with cables arranged in trefoil formation."
http://www.ellispatents.co.uk/elec_home.html

"Three-phase single core electric power cables of 35 kV rated voltage are taken as an example. Two laying conditions (trefoil and flat formation) are considered..."
http://www.eihp.hr/~mmajstro/Calculation_of_losses.pdf

And I think this link may be relevant:

"XLPE cable 1600 mm2 Cu
Trefoil formation
2 cables/phase
XLPE cable 2500 mm2 Cu
0.5 m spaced
1 cables/phase
OHL
Indicative
figures
400 kV"
http://www.thor.edu/symposium/download/presentations/gertaan...