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Just some work pics

Discussion in 'Cranes' started by crane operator, Aug 20, 2016.

  1. Kiwi-truckwit

    Kiwi-truckwit Senior Member

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    That's about as close as I wanted to get to a live circuit. My loader crane (the red one) was inside the switchyard, from memory it was "only" a 55 kVa, but that's enough to leave a mark IMG_20140312_084345.jpg
    Somewhere I have photos of transmission line work with a bucket mancage, but I can't seem to find it.
     
  2. DMiller

    DMiller Senior Member

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    The field strength is the Killer, literally. A 7200 line as typical for service around here only has around a 1-2' field around the cable that if you as a ground enter will Arc TO You(Easiest source to ground), where I worked was 345kv, had a SEVEN Foot Circumferential Field where anything got within seven feet it would be incorporated into that field, that is why birds do not fly close to the big Hi Lines as they can Feel that field. Grounding only does so much as generally is done at both ends of a dead cable, anything metal in contact or close proximity will still build static charges that have to be dissipated or can be life threatening. We lost a Electrician at my previous employer to that, he grabbed a recently Ungrounded cable that had built a static charge(DC) popped him and killed him wile still grounded at the Other end. The Earth magnetic field can build a charge in long lays of cable, to the level can be Several HUNDREDS of DC Volts and will still kill you if you are grounded.
     
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  3. Kiwi-truckwit

    Kiwi-truckwit Senior Member

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    We've experienced that before, piling 8 metres from a 220kVa circuit. The reo cage hanging from the crane built up a static charge that was released when the guys on the ground touched it to guide it into the ground.... We got representatives out from the transmission company to tell us why it was happening and how to prevent it.
     
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  4. DMiller

    DMiller Senior Member

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    Only thing can do is hard Ground EVERYTHING. We would use Hot Sticks to connect grounding lanyards to Scaffolding or machines sitting long term in the switchyards, could build enough capacitant charge to light one up.
     
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  5. Flat Thunder Channel

    Flat Thunder Channel Well-Known Member

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    We had a repair come in last year. A high power transmission line arced to one of the cylinders on the loader. I asked the service tech to send me a photo. If I ever get one I will post it. The amount of damage was impressive /scary depending on how you think about it. Good thing no one got injured it, but it did leave the operator with his crane stuck in a tree.
     
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  6. crane operator

    crane operator Senior Member

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  7. petepilot

    petepilot Senior Member

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  8. DMiller

    DMiller Senior Member

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    Quite a ride!
    Windy, would presume they could have been warned
     
  9. Flat Thunder Channel

    Flat Thunder Channel Well-Known Member

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    arced-cylinder.jpg This is a cylinder that got a little too close to high voltage. It vaporized the steel! Now that is scary high power arcing!
     
    doublewide, hvy 1ton, DMiller and 2 others like this.
  10. DMiller

    DMiller Senior Member

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    Just like arc gouging with a welder!!
     
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  11. Flat Thunder Channel

    Flat Thunder Channel Well-Known Member

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    I thought the same thing! Glad I wasn't the one operating the crane! Luckily no one was injured, but it developed into an expensive day on the job.
     
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