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Overhead Line Clearances

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  • 05-06-2015 2:49pm
    #1
    foxy farmer
    Registered Users Posts: 3,194 ✭✭✭


    Could anyone throw up any up to date measurements for ground clearance across open country for LV and 10/20KV networks?
    ESB website has no info.
    Local contractor has encountered some ridiculously low pieces of network in some new fields being cut for silage this year.


Comments

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    #2
    punisher5112
    Registered Users Posts: 24,644 ✭✭✭✭punisher5112


    If they are unsafe or you feel they are unsafe contact ESB immediately.


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    #3
    Luckysasha
    Registered Users Posts: 1,042 ✭✭✭Luckysasha


    Ring ESB immediately. The low sag could be caused by a broken stay or pole somewhere along the network. It is imperative this is reported immediately as to avoid anyone being injured. Don't worry there won't be a charge for calling them out. 1850 372999 just have your MPRN number (on top of your bill) to hand so they know exactly where you are.


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    #4
    adrian92
    Registered Users Posts: 566 ✭✭✭adrian92


    I confirm previous advice.

    Do not let your contractor work - especially if operating high machinery.

    Getting close to 20kV lines can have a bad result

    ESB Networks will respond (possibly to save a life)


    Please act.


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    #5
    Youngblood.III
    Site Banned Posts: 777 ✭✭✭Youngblood.III


    There should be 15m from the highest point of the machines


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    #6
    Luckysasha
    Registered Users Posts: 1,042 ✭✭✭Luckysasha


    @ Youngblood lol the poster is asking about 10 / 20 kv clearances. You would be lucky to get 15m clearance on a 110kv line


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    #7
    Youngblood.III
    Site Banned Posts: 777 ✭✭✭Youngblood.III


    My bad..... machines should make sure if keep at least 10m away from 110kv lines due to risk from arcing

    Regs...
    522.6.10 Overhead conductors.
    Overhead conductors shall have a vertical clearance from the ground of at least 5.5m. (Maybe greater for like of roads, railways etc)


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    #8
    Youngblood.III
    Site Banned Posts: 777 ✭✭✭Youngblood.III


    6m for LV 10kv 20kv 38kv
    10m for 110kv, 200kV 400kV


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    #9
    foxy farmer
    Registered Users Posts: 3,194 ✭✭✭foxy farmer


    Youngblood.III wrote: »
    6m for LV 10kv 20kv 38kv
    10m for 100kv, 200kV 400kV

    There was a figure back over 20 yrs ago that oh lines should have a clearance of 20ft across open countryside. Granted exceptions will occur but ive seen 3 locations in the last week where 14ft would be a good guess.


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    #10
    Youngblood.III
    Site Banned Posts: 777 ✭✭✭Youngblood.III


    foxy farmer wrote: »
    There was a figure back over 20 yrs ago that oh lines should have a clearance of 20ft across open countryside. Granted exceptions will occur but ive seen 3 locations in the last week where 14ft would be a good guess.

    If they're 110kv kv should should report it.


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    #11
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Youngblood.III wrote: »
    My bad..... machines should make sure if keep at least 10m away from 110kv lines due to risk from arcing

    Regs...
    522.6.10 Overhead conductors.
    Overhead conductors shall have a vertical clearance from the ground of at least 5.5m. (Maybe greater for like of roads, railways etc)

    In reality even 110kv wont jump anything like 10 meters. A few inches at most.

    But large clearances are needed for safety margins.

    It will of course arc a few meters once contact is made, or close to contact, and the arc has begun and the gap opened.


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    #12
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    From what I can understand.... No No, 110v lead I said.
    https://www.youtube.com/watch?v=h9PUVQaeI0k


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    #13
    Youngblood.III
    Site Banned Posts: 777 ✭✭✭Youngblood.III


    Bruthal wrote: »
    In reality even 110kv wont jump anything like 10 meters. A few inches at most.

    But large clearances are needed for safety margins.

    It will of course arc a few meters once contact is made, or close to contact, and the arc has begun and the gap opened.

    Also depends on air quality..moisture %


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    #14
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Youngblood.III wrote: »
    Also depends on air quality..moisture %

    True, but the distance it will jump from a live line to a ground based machine will not vary much from the extremes of dry to the high humidity, in comparison to what would be deemed the safe clearance distance for machinery.

    Its apparently about an inch per 75kv to jump an air gap. That`s one experiment Ill be avoiding anyway.


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    #15
    Luckysasha
    Registered Users Posts: 1,042 ✭✭✭Luckysasha


    One inch to every 75kv is way off. The close proximity zone for 38kv is 1 meter. I could state every clearance from LV right up to 400kv but I don't want people thinking it's ok to get that close. Bottom line is stay as far away as you can from overhead lines and if in any doubt call ESB immediately


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    #16
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Luckysasha wrote: »
    One inch to every 75kv is way off. The close proximity zone for 38kv is 1 meter. I could state every clearance from LV right up to 400kv
    No need, I seen them all before in the 80s.

    But anyway, you are misreading the post. I never said the clearance is 1 inch per 75kv. I said the gap the voltage will jump is about 1 inch per 75kv, which was just a matter of interest. Bit of a difference between clearance distances/proximity zones, and distances a voltage level will jump.

    The gap in lightning arrestors on 38kv lines will be far less than a meter, for example.

    The advice for keeping away from them is to keep well away. And onto ESB if any doubts at all about line heights around machinery etc.


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    #17
    foxy farmer
    Registered Users Posts: 3,194 ✭✭✭foxy farmer


    To be quite honest lads I think some lines are strung up without regard for sag or correct clearances. My agri contractor has encountered at least 4 locations 2 of which are HV 10-20KV that are well below safe height. Harvester chute getting stuck in these would be fatal. The ESB have to construct their networks to a certain standard. No good putting the onus back on us by telling us to be on the look out. Hard to prove the actual height of an oh line after pulling it down.


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    #18
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,595 Mod ✭✭✭✭2011


    foxy farmer wrote: »
    To be quite honest lads I think some lines are strung up without regard for sag or correct clearances. My agri contractor has encountered at least 4 locations 2 of which are HV 10-20KV that are well below safe height. Harvester chute getting stuck in these would be fatal. The ESB have to construct their networks to a certain standard. No good putting the onus back on us by telling us to be on the look out. Hard to prove the actual height of an oh line after pulling it down.

    If you are concerned about any lines I would suggest that you photo them and attach the photos along with GPS coordinates to an email to ESB Networks voicing your concerns. I would be very surprised if this doesn't result in a prompt response.


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    #19
    Luckysasha
    Registered Users Posts: 1,042 ✭✭✭Luckysasha


    @ Foxy farmer I think you have hit the nail on the head. The onus is on the man driving around the field with machinery. I see this from both sides I work for ESB but I also live on a farm so I see the dangers from both sides. The networks are constructed to a EU standard but the man driving the machine has to be responsible for his own safety. It doesn't matter how high you put the lines something will be able to reach them. During the boom we where flat out dealing with calls of teleporters hitting lines even cranes. So without trying to start an argument please be responsible for your own safety and if in any doubt ring ESB


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