utility question

[peter d]

Here's one that has me stumped.

The utility high voltage conductors and the low voltage conductors (like on your average street where there might be 7200 on top and of course, 120/240 on the bottom) share the same grounded conductor.

If this grounded conductor is cut, at what voltage will it be "live?"

 

[mdshunk]

Depends on the resistance/conductance of the earth where ever you reference that conductor. Since that conductor is multigrounded at so many points, I'd have to guess almost zero if it was cut on the primary side, and almost 120 if it was cut on the secondary side.

 

[peter d]

I see, so it wouldn't suddenly have potential at 7200 volts? (Or whatever the primary is)

 

[LarryFine]

If this grounded conductor is cut, at what voltage will it be "live?"

There are too many variables to give a simple answer, such as a thousand and one places to cut such a wire, but with as many redundant grounding points as there are in a typical system, the probable answer is that a single cut would have little effect.

 

[mdshunk]

I see, so it wouldn't suddenly have potential at 7200 volts? (Or whatever the primary is)

Hang on a minute... I'm going out back to try it...

 

[LarryFine]

Hang on a minute... I'm going out back to try it...

Lemme grab my camcorder!

 

[peter d]

I can't take the suspense anymore. I'm getting the bolt cutters.

 

[72.5kv]

lost neutral

lost neutral

the neutral on a typical 12.47Kv/7.2 wye distribution is grounded at every pole, this also include the include bonding it to the guy wires that support the poles. Also the tie between the utility and service neutral. this makes for several parallel back to the source. like the previous poster mention. it would take a break at several point.

 

[Terrynistler]

oh oh Marc never came back. Guess it wasn't 120. May we all bow our heads and pray for god. He's gonna need it with Marc up there

 

[LarryFine]

oh oh Marc never came back. Guess it wasn't 120.

 

[mdshunk]

Oh, c'mon. I was just teasing.

 

[robbietan]

Here's one that has me stumped.

The utility high voltage conductors and the low voltage conductors (like on your average street where there might be 7200 on top and of course, 120/240 on the bottom) share the same grounded conductor.

If this grounded conductor is cut, at what voltage will it be "live?"

must be one of the"older" installations where they ground the primary and the secondary in one conductor. saves on copper....