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Liar Liar! Pants on Fire! Hanging upside down from a telephone wire!

Rubycon

Rubycon

Madame President
This liar was so hot his pants were on fire on that wire.

http://www.youtube.com/watch?v=Y4lQ1vzTFf0&

Or the Doc just sent someone back to the future...

Ok so what it looks like is a fault on the (unfused) secondary and the current is sufficient to make that wire glow incandescent. Since it's at night you don't see the plumes of black smoke from the burning insulation...

This is why you don't take tree pruning sheers to that wire running down the wall from the overhead feeders. (the drug laden copper thieves don't care) Unlike a wire in your home protected by an Edison fuse or circuit breaker, this one will just heat up while the pole pig grunts. The light show continues as the primary current usually doesn't blow a fuse or engage a recloser. Pretty dangerous. It's the most common cause of meter fires too.
 
Rubycon said:
This liar was so hot his pants were on fire on that wire.

http://www.youtube.com/watch?v=Y4lQ1vzTFf0&

Or the Doc just sent someone back to the future...

Ok so what it looks like is a fault on the (unfused) secondary and the current is sufficient to make that wire glow incandescent. Since it's at night you don't see the plumes of black smoke from the burning insulation...

This is why you don't take tree pruning sheers to that wire running down the wall from the overhead feeders. (the drug laden copper thieves don't care) Unlike a wire in your home protected by an Edison fuse or circuit breaker, this one will just heat up while the pole pig grunts. The light show continues as the primary current usually doesn't blow a fuse or engage a recloser. Pretty dangerous. It's the most common cause of meter fires too.
Click to expand...

that's exactly what i thought 😀
 
DrPizza said:
Copper thieves should be lined up and shot.
Click to expand...

They usually get "theirs" when attacking distribution lines. 😉
Funny thing is some have gone through loops to get copper only to find out - well after the authorities find them dead - the wires they cut were actually aluminum! 😀
 
One of the risks of high-impedance, low-voltage supplies. They may not trigger an over-current protection device in the event of fault conditions.

This is one of the reasons why 110 V power is so much more dangerous that 230 V (in terms of fire risk. 2 fires per 10,000 households per year due to faulty wiring in the US, 1 fire per 10,000 households per year in Europe. Applicance fires are about 2/10,000 per year in both areas.

The number of deaths/injuries from fire dwarf those from electrocution/electric shock in both regions.
 
Mark R said:
One of the risks of high-impedance, low-voltage supplies. They may not trigger an over-current protection device in the event of fault conditions.

This is one of the reasons why 110 V power is so much more dangerous that 230 V (in terms of fire risk. 2 fires per 10,000 households per year due to faulty wiring in the US, 1 fire per 10,000 households per year in Europe. Applicance fires are about 2/10,000 per year in both areas.

The number of deaths/injuries from fire dwarf those from electrocution/electric shock in both regions.
Click to expand...

Having more capacity per plug is also very nice too. 😉

Jeffg010 said:
I wonder if a bird was sitting on that wire when that happened.
Click to expand...

A bird would take off far before heat would be detected. When a fault occurs the magnetic field around the wire is tremendous. Often it can be seen as a jiggling or even galloping motion briefly.

Faults in branch circuits wired with THHN in conduit often are "felt" a great distance away as the conductors inside the EMT rattle briefly. While not as much current as a direct "across the phase" short, foolishly depressing the plunger of a contactor on a motor starter when its overload has tripped due to locked rotor - for example - can cause a similar effect on the wiring.
 
Mark R said:
One of the risks of high-impedance, low-voltage supplies. They may not trigger an over-current protection device in the event of fault conditions.

This is one of the reasons why 110 V power is so much more dangerous that 230 V (in terms of fire risk. 2 fires per 10,000 households per year due to faulty wiring in the US, 1 fire per 10,000 households per year in Europe. Applicance fires are about 2/10,000 per year in both areas.

The number of deaths/injuries from fire dwarf those from electrocution/electric shock in both regions.
Click to expand...

so why are lights at work 277v instead of 110v?
and why such an odd #?
 
JEDI said:
so why are lights at work 277v instead of 110v?
and why such an odd #?
Click to expand...

Most commercial/industrial plants use 480V three phase power. Lighting is single phase. If you take a single leg to ground you get 277V.

In common 208V three phase systems phase to ground is 120V. 120V is what most standard appliances in the US run on.
 
I like how the video is critical of the firemen. What did they want, them to start squirting the burning wire with water.
 
Pray To Jesus said:
Why not design apps that runs at 500V?
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Stolen from http://www.practicalmachinist.com/vb/transformers-phase-converters-vfd/440v-460v-480v-what-gives-103088/

" Semantics.
There are 2 "voltages" to be concerned with. One is the "Distribution Voltage", meaning what the utility gives out; the other is the "Utilization Voltage" which is what the device or motor is designed to use. Because the US power "grid" as we know it now was originally a big bunch of unconnected separate producers, each producer had their own standards. Large ones early on such as New York, Chicago, Boston etc., were where the biggest market for electrical products were, so manufacturers tended to cater to them and their standards. This ultimately had the effect of driving other smaller utilities into conformance because their users sometimes found it difficult to find appliances and machinery that would work at odd voltages. 460 was chosen by NEMA (National Electrical Manufacturers Assoc.) as the compromise utilization Voltage because it was mid way between 440 and 480, and they also specify that motor HP and torque ratings would be based on a +-10% voltage level from there. So a 460V rated motor can tolerate any voltage from 414 to 506V. The same is true for 230V as the compromised Utilization Voltage, because motors can then tolerate from 207 to 253V, although most new motors are designed now to accept from 200-250V because of 208V systems. 115V is the compromise between 110 and 120V, although at that level you still see ratings all over the map because it really doesn't matter.

If you pay attention, you won't see motors with nameplates that say 480V (unless they were specially wound for someone). You will however see VFDs that say 480V, because they are referring to the VFD's voltage tolerance, not the motor you connect to it. In a VFD, the output voltage can be lower than the input voltage, so you tell the VFD what the motor nameplate says anyway.

If you have a 3 phase motor that says 440V or 220V on the nameplate, it was designed specifically for that voltage, which means it is pre-NEMA. That also means you don't necessarily know the voltage tolerance if it's not stamped on the nameplate, so be careful."
 
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SirStev0 said:
I like how the video is critical of the firemen. What did they want, them to start squirting the burning wire with water.
Click to expand...

Usually they will make sure it doesn't spread by hosing down areas around the poles and where the burning drips are falling. When dealing with blowouts Askarel fires can be quite hazardous. Hosing live feeders definitely is something you would not want to do!
 
Rubycon said:
This is why you don't take tree pruning sheers to that wire running down the wall from the overhead feeders. (the drug laden copper thieves don't care) Unlike a wire in your home protected by an Edison fuse or circuit breaker, this one will just heat up while the pole pig grunts. The light show continues as the primary current usually doesn't blow a fuse or engage a recloser. Pretty dangerous. It's the most common cause of meter fires too.
Click to expand...
The early bird get the worm, but the second thief gets the copper.
 
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