utility question

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  #1  
Old 03-03-06, 09:46 AM
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utility question

The thread about emergency generator power reminded me of a couple of things that remain unanswered in my head from last year. If someone has some utility transmission training, that may help to answer.
A boy was electrocuted in my city last year by a fallen power line. It turns out, it was the line that powered the streetlights. The paper claimed it was a 440v line and apparently is only energized at nite. It appeared the wire was "safe" in the day, but tragically became energized at nite, when he grabbed it. Does this sound reasonable?

The other part of this story, is that I had a fallen wire in my front yard for about a week (from this same storm). I swear I saw sparks at one point, but they seemed to stop. The line was a secondary line, I visually traced this wire to the streetlights also. Cars were driving over this wire for a couple of days, AFTER I called the POCO. The POCO was too busy with 250kv lines down, I suppose and actually used fire/rescue to deal with the "low voltage" issues. I then flagged down a fire rescue truck that had a 3' pole that was a power detector. It was defective, and the fireman ultimately kicked the wire into my lawn, and then went ahead and grabbed it with a gloved hand and wound it up into a coil and kind of attached it to the wood pole at about eye level. They left it connected at the pole, since they don't climb poles. If this sounds rather chaotic, it was a wild time we had post Wilma. My nearest gas station actually had a small generator, and the insuing fights and lines required 2 cops there full time. My daily jogging path contained 3 phase lines on the ground for several blocks, poles and all. This was for a solid week.
So, I suppose i'm trying to get more informed about the different voltages I'm likely to experience this season in my front yard.
 
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Old 03-03-06, 12:04 PM
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In my City each street light has its own photo sensor that turns on that light, the lines are live at all times.
on a cloudy day some lights will be on and some will be off.
Some times you can see the round sensor on top of the light.

As to any wires, always assume they are live at all times.
There are circuit breakers that automatically reset, a line maybe dead then live in seconds or minutes.
People were killed from dead lines that were automatically reset.

Not all fireman know what they are doing when it comes to electricity.
 
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Old 03-03-06, 12:59 PM
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We had a similar bad situation with Ivan. Some numb nut hooked his generator directly to his infeed buss bar so he could have electricity. No Generac or switch gear at all. One of our local power company guys was near the wire when this guy powered up his generator. Needless to say reverse voltage doubled going backwards through the transformer hitting him with 12000 volts.
 
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Old 03-03-06, 02:44 PM
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Originally Posted by telecom guy
It appeared the wire was "safe" in the day, but tragically became energized at nite, when he grabbed it. Does this sound reasonable?
That is certainly a reasonable explaination. Most streetlamps have their own light sensors, but these ones could share a sensor or be timed instead. As you indicated with quotes, a wire dropped from a pole is never, ever safe.

I swear I saw sparks at one point, but they seemed to stop. The line was a secondary line, I visually traced this wire to the streetlights also.
It could have been fused and the fuse finally blew, or the transmormer failed, or a wire melted somewhere, or a recloser (automatic breaker reset) on the primary or the linemen working on higher voltages disconnected its source.

The POCO was too busy with 250kv lines down, I suppose and actually used fire/rescue to deal with the "low voltage" issues.
Not ideal, but desperate times... Most fire departments do have hot sticks or fiberglass poles available to move energized lines if they absolutely have to.

the fireman ultimately kicked the wire into my lawn, and then went ahead and grabbed it with a gloved hand and wound it up into a coil and kind of attached it to the wood pole at about eye level.
If the wire was live it probably would have arced when he kicked it. Not the best move, but leaving it lay there isn't a great option either. He may have known that the POCO had de-energized those lines upstream.

So, I suppose i'm trying to get more informed about the different voltages I'm likely to experience this season in my front yard.
I understand your remark is a bit tounge-in-cheek, but it would be totally reasonable to have lines up to 20 kV in residential areas; 4kV and 13kV are common residential primary voltages.
 
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Old 03-03-06, 09:37 PM
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Originally Posted by telecom guy
My daily jogging path contained 3 phase lines on the ground for several blocks, poles and all.

Don't take this too personal, but if your neighborhood was wiped out by a hurricane, and you have nothing better to do than take a little jog after dinner, how bad can it be?
 
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Old 03-04-06, 09:41 AM
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We didn't have it "bad" at all. Just no power for 2 weeks. We were hit with just a strong Cat 1 hurricane and my local power infrastructure fell down. No sympathy expected, save that for those folks that lost homes, jobs, and maybe even family members.
 
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