Arc Flash [telecom]

Oct 29, 2012 2 Replies

I've seen the safety films.



I've seen the Utube videos.



I've seen the demonstrations.



/Nothing/ compares to what I saw tonight.



Right after I last wrote, I went out to get some more gas, just to have it on hand. On the way home after a trip to the gas station and the supermarket (which was nearly deserted, btw), I was taken aback by a "Detour" sign blocking the road: a tree had fallen across it while I was shopping. I started to make the turn onto the alternate route.



The sky lit up like God's own welding torch. It was an hv arc flash, which lasted over thirty seconds. I went down the road, and saw some smoke coming across, but no wires, so I kept going, but when I got up to the smoke I realized that the hv line was lying across someone's lawn, burning the grass.



I told the fire department.



I'm back on the generator just for long enough that my wife could cook dinner. I'll stop now.



Stay safe!



Bill


Good advice ('Stay Safe!") but I doubt it compares to this, the most active lightning location on Earth with over 8,000 lightning strikes a night:

1:15

1:49

5:45

2:01

2:43

:-)

Yowch!!

Many years ago, I saw, from 3 blocks away, a crane swing its boom into a HV feeder line (10s of KV, between a 141kv step-down station and a 'local' substation), about 500 ft outside the step-down station perimeter fence. A sheet of flame 100+ ft wide, and 30-40 ft tall -- nearly blinding in broad daylight. 5+ seconds later, two 'somethings' blew (explosively!!) _inside_ the step-down station and the whole territory went dark. Don't know if it was a safety device or something self-detracting from the 'short'.

Biggest 'arc' I ever saw was a lightning bolt that struck a wooden utility pole about 50 ft away from me. Spilt the pole from the top about halfway to the ground. This was at night, so it was truly blinding.

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