Grounding a boom lift???

[duke31329]

I am currently working at a combined cycle power plant and I have been working on electrical equipment for 25+ years but I am NOT a lineman I don't mess with 230kv. I have to change out some light fixtures about 30 feet outside our switchyards. I am using a Genie boom lift and when I get close to the fixtures there is a significant amount of static that builds up. The boom lift is not grounded and my concern is that by grounding the lift doesn't that increase the difference in potential from the light fixture to the basket and more importantly me? I have read in the forum that the bucket be grounded to work around energized equipment and this doesn't make sense to me. Insulating the bucket and therefor removing the potential makes more sense to me. Can someone give me a hand and help make some sense of this? Thanks in advance for any help.

 

[hurk27]

First working anywhere around that high of voltage requires extra special precautions, bonding the boom to the light pole or fixture will depend on if your boom is insulated and how much, most booms will say the max voltage there insulated to, and most I have seen only go as high as 25kv, I would say you might have to use a bond on stick between your basket and pole, or light fixture, I did a street light install under a 500kv line, and while I was no where near the approach boundary for the HV lives, the light pole and or the bucket truck built up a difference of potential of several hundred volts, very little current but would still knock the heck out of you, so we use one run of a 40' jumper cables to to bond the bucket truck to the pole, we kept the circuit conductors bonded to ground also as they were URD and would also build up a charge till we had them tied in.

Make sure you maintain you approach boundaries to the HV lines, I think it's 20' for 250kv, I would stay 30' away, if the Genie boom is not insulated, just bond between the genie and the pole or light fixture, grounding it to earth does not always remove a difference of potential.

 

[duke31329]

Thanks for the help.

Thanks for the help.

Hey Huck thanks for the help, bonding the lift to the pole seems to make a lot more sense to me. We will have to reexamine our procedure for this type of evolution to prevent issues like this from coming up in the future. Thanks again for your help.