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In some very rare cases, a higher voltage transmission line (maybe 57-115 kV) can drop down onto distribution lines and thereby raise the distribution voltage by an order of magnitude for a brief (fraction of a second) period. As exciting as this can be (light bulbs get real bright and the electronics all get fried), I don't recall anyone ever being injured when this happens. Still I wouldn't want to be wrapped up in an electric blanket at the time...
It would be quite rare indeed.
When the 33Kv wire dropped on local distribution, then electric meters literally exploded from their pans. At least 100 of them.
When the 33Kv wire dropped on local distribution, then electric meters literally exploded from their pans. At least 100 of them. That sounds like the Moores Mill Road incident that occurred in '88.
http://www.youtube.com/watch?v=Dmy9CHCewtg
Fortunately those kinds of ocurences are rare. What happened on that day is possibly the worse thing imaginable. When OCP fails and the faults are allowed to play on for literally hours, very bad things can happen. Fortunately no one was killed or seriously injured. Time of day where most people were at work most likely played a big role.
The issue at hand here say compared to lightning induced spikes and surges is duration. The secondary electrical system at the customer premise is designed to arc to ground at breakdown potential of approx 6.6 kV. If a severe surge/impulse comes down the line, it will flash over and safely run to ground in properly installed wiring. Of course, this still puts loads downstream at 6.6kV but the flashover is effectively a short circuit and most MOV/VSP devices can easily handle this as long as the wiring is properly designed and ground conductors are effectively bonded.
When a 33kV line comes in contact with a 13kV line and the OCP (recloser/ACOCB, etc) fail to open in a timely manner, all hell breaks loose. The severe overvoltage can flash over the 13kV primaries and be introduced directly to the secondaries! This is bad as the duration of this event (even with delayed RC trip) is far longer than a spike from a lightning strike nearby. Since the wire insulation is rated at 600VAC, breakdown will occur but unfortunately not fast enough. (If/when breakdown occurs, the arcing will happen away from premises, but the damage is done.) This allows voltages to be present at the customer premise wiring up to thirty times normal. Loads rated for 240 (dual pole) are essentially shorts at this overvoltage. Severe arcing and heating occurs immediately and is very destructive. It can also raise the potential of normally grounded parts of the dwelling to levels that would give a lethal shock. Load centers, meter sockets, and things downstream are severely damaged or destroyed. Surge protectors, even those designed for whole house protection; are not designed for this condition. This condition would require an engineered solution costing tens if not hundreds of thousands of dollars for each customer. Fortunately this practically never happens. But it did on 23 August 1988. And this is why this example is used in training of persons that work in the field. It's one of those things we never want to see happen. And of course it could have always been worse.
The more distance one is from the fault, the lesser of a chance of injury.
An electric blanket is a low watt density load. Fortunately for the user in such a condition most of the energy would be dissipated at the service entrance. But if you have subpar wiring with poor or no grounding, watch out! Mister Sparky is your worst nightmare, far worse than the Boogieman (because Mr. Sparky actually exists!).
You most likely have a higher chance of getting shocked using an electric blanket from a frayed cord, a pet urinating on it and stray current shocking you (not lethal but enough to be rather unpleasant!) or whatever else in the 1000s of things that happen in the bed at night. But that's a personal matter.
Most of the time during snow events where the snow is heavy enough to cause a fault there will be a brief interruption that gets cleared quickly. Sometimes a tree limb that was not trimmed back due to lack of a tree maintenance program, etc. can touch wires. In cases were entire trees come down and bring the wires on top (33kV) down to touch the 13kV lines, etc. the OCP swings into play and the only thing the customer experiences is a dark and cold house. A light show if you're close.
http://www.youtube.com/watch?v=34r6RGF2JLA
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