question on grid lines

ws9876
ws9876 Solar Expert Posts: 450 ✭✭✭
in PV Installers Forum - NEC, Wiring, Installation #1
The power line next to my house is about the smallest size I think.... maybe 3200volts. The single phase line wire is really small. I was looking up at a jct where another line runs up to a small cell tower. The upper line was connected with a jumper. I assume this is incoming hot.
But the bottom lines were not connected at all, but both had small jumpers to the ground
that goes down the pole and into the dirt.
Why werent the bottom lines connected and what is the story..???? Is this a neutral??
please explain..
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  • RCinFLA
    RCinFLA Solar Expert Posts: 1,485 ✭✭✭✭
    #2
    Re: question on grid lines
    ws9876 wrote: »
    The power line next to my house is about the smallest size I think.... maybe 3200volts. The single phase line wire is really small. I was looking up at a jct where another line runs up to a small cell tower. The upper line was connected with a jumper. I assume this is incoming hot.
    But the bottom lines were not connected at all, but both had small jumpers to the ground
    that goes down the pole and into the dirt.
    Why werent the bottom lines connected and what is the story..???? Is this a neutral??
    please explain..

    Let's just stop right here. You cannot judge or do anything about the setup other then call your utility and make a complaint, if you have something that is causing you a problem.

    The lowest HV line is about 7.5 kV and that is usually for underground lines. Most residential overhead lines are 25kV. "small size" has nothing to do with what voltage the line is, it is related the current load the line must support. A 200 amp service for split phase 240 vac turns into only 2 amps off a 25 kV feeder line.
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  • Frxddy
    Frxddy Solar Expert Posts: 113 ✭✭✭✭
    #3
    Re: question on grid lines

    I honestly do not know what "local lines" carry for voltage. I do know that (at least in this area) when you look at wires on a pole from top to bottom they are: Power (1,2, or3 lines), next down is a single wire ( grounded, some call it neutral), next is Cable (TV, Internet) and the bottom one if phone.
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  • mikeo
    mikeo Solar Expert Posts: 386 ✭✭✭
    #4
    Re: question on grid lines
    But the bottom lines were not connected at all, but both had small jumpers to the ground that goes down the pole and into the dirt.
    The journeyman electricians on this site can better answer your question but I have heard of installations where only a hot feeder is run to the service from a transformer. The neutral is grounded at both ends hence only one wire visible. I don't know what circumstances this was used in or if it is to code any longer.
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #5
    Re: question on grid lines
    mikeo wrote: »
    The journeyman electricians on this site can better answer your question but I have heard of installations where only a hot feeder is run to the service from a transformer. The neutral is grounded at both ends hence only one wire visible. I don't know what circumstances this was used in or if it is to code any longer.

    I've seen this years ago in a remote area of the Province, but it was only with the high voltage being supplied to transformers for remote settlements. There would be only one wire on the poles to supply the transformers, and the "return" was ground. Often wondered if the houses along that line had brighter lights after a heavy rain. :p
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  • RCinFLA
    RCinFLA Solar Expert Posts: 1,485 ✭✭✭✭
    #6
    Re: question on grid lines
    waynefromnscanada wrote: »
    I've seen this years ago in a remote area of the Province, but it was only with the high voltage being supplied to transformers for remote settlements. There would be only one wire on the poles to supply the transformers, and the "return" was ground. Often wondered if the houses along that line had brighter lights after a heavy rain. :p

    I find this hard to believe as it would be quite dangerous. I have heard of thiefs removing neutral utility pole wires to sell for savaged wire.

    I read in newspaper last week that Interstate-95 light poles in Miami are having trouble with copper wire in buried conduit being stolen from between light poles. They are stealing the wire during daylight hours when lights are deactive.
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  • johnl
    johnl Solar Expert Posts: 30 ✭
    #7
    Re: question on grid lines

    http://en.wikipedia.org/wiki/Single-wire_earth_return

    Used mainly for long distance rural lines. Although I'm not sure if this is really what the original thread starter post is about.
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  • ggunn
    ggunn Solar Expert Posts: 1,973 ✭✭✭
    #8
    Re: question on grid lines
    RCinFLA wrote: »
    I find this hard to believe as it would be quite dangerous. I have heard of thiefs removing neutral utility pole wires to sell for savaged wire.

    I read in newspaper last week that Interstate-95 light poles in Miami are having trouble with copper wire in buried conduit being stolen from between light poles. They are stealing the wire during daylight hours when lights are deactive.
    Thieves are getting more sophisticated all the time. A theatre company here in Austin bought a building, but when they got ready to move in, they found that all the copper conductors between the building and the street were missing. Someone working in the store next door witnessed the daylight theft; she said the thieves had used a truck with a lift bucket and were wearing hard hats and uniforms, so she assumed they were with the city/utility.
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  • RCinFLA
    RCinFLA Solar Expert Posts: 1,485 ✭✭✭✭
    #9
    Re: question on grid lines
    johnl wrote: »
    http://en.wikipedia.org/wiki/Single-wire_earth_return

    Used mainly for long distance rural lines. Although I'm not sure if this is really what the original thread starter post is about.

    Well, I guess Nikola Tesla is jumping up and down in his grave. Probably due to the current flowing through his casket. ;)
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  • solarvic
    solarvic Solar Expert Posts: 1,071 ✭✭✭✭
    #10
    Re: question on grid lines

    Copper thieves will go to any links to get copper. Someone at the local cemetary broke open a mausileam and had the copper casket part way out before someone scared them off. Coronor had to check that body was still in coffin. :grrsolarvic:grr
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #11
    Re: question on grid lines
    RCinFLA wrote: »
    I find this hard to believe as it would be quite dangerous. I have heard of thiefs removing neutral utility pole wires to sell for savaged wire.

    I read in newspaper last week that Interstate-95 light poles in Miami are having trouble with copper wire in buried conduit being stolen from between light poles. They are stealing the wire during daylight hours when lights are deactive.

    This was up through the very thinly populated mountainous areas of The Cape Breton Highlands, of Nova Scotia, and there was no mistaking it. One wire, on insulators, from pole to pole to pole, mile after mile between transformers. Whether it's still that way I cannot say, haven't been up that way for probably 20 years or more. Agree, would be deadly if the ground ever failed. That thought hadn't crossed my mind at the time, but the relatively high resistance of return through ground certainly did.
    Re copper wire being stolen from underground conduit between street lights, the same thing is happening here too. Disgusting!
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #12
    Re: question on grid lines
    RCinFLA wrote: »
    Well, I guess Nikola Tesla is jumping up and down in his grave. Probably due to the current flowing through his casket. ;)

    Very interesting link you provided, thanks for sharing! :D
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