Our fence consistent of 4 strands of nautical grade electric rope (7mm, not the thin stuff) hung on treated wooden posts 16'apart with screw in insulators. The top and third strand are electrified. We have used this and only this for the past 2 1/2 years to keep our four horses in with very few problems. I had one strand come undone this week partly because the fastener was a bit loose (cold shrinkage) and partly because my draft cross was pawing at the bottom wire to get at a new mare across the fence. The rope didn't break, it simply came undone at the joiner, but held at the next insulator. The three strands above it were fine. This was also the non-electrified strand. I'm pretty sure all my horses knows which strands are hot and which are not as they get very close to the fence but don't often get zapped.
This type of fence works well in all weather and is easy to maintain. It is important however to use a good charging unit, ground it properly and select good posts for support. I notice our fence does tend to expand and loosen a bit in the cold, so I do check it regularly in the winter. For reference, our temperatures range from +35C in the summer and can go down to -45C in the winter. The fence takes this, no problem. Even with 2 feet of snow on the ground, the conduction is good at -40 (as I found out the day before last).