This incident took place in Rhode, Co. Offaly Ireland.http://www.youtube.com/watch?v=OHvnXH1_6Kk
Warning : There is some coarse language in the video as local residents watch in horror as their town's overhead power lines literally fry before their eyes.
These are 220/380V 3 phase installations, extremely old installation.
1) How did this happen?
2) Why didn't the fuses/breakers trip - it seems that the system almost burned itself out rather than tripping.
3) Why were the wires sagging...
Question has to be asked, was that installation completely overloaded and over-fused?
That installation dates from the original rural electrification era. So, could be anytime from 1946 onwards.
It would be quite a short run of 3-phase cable just serving a little village. Typically, that system would be fed from a 10 or 20kV local distribution MV line.
Apparently one of the poles further along had been damaged, resulting in the extreme sagging of the overhead wires.
However, I'm only going on someone's blog for that info!
The entire LV run would quite likely have been very short, just a few poles, so it's quite possible that an end pole was damaged.
There is an on-going project (multi billion euro) to replace and upgrade much of the original electrical gear that is now well life-expired.
However, that incident would leave a lot of questions for the local Networks team to explain!!!