Grounding Conductor to Automated People Mover
Grounding Conductor to Automated People Mover
(OP)
In a transportation tunnel we are building we have installed a grounding grid under the concrete slab. Prior to pouring the concrete a waterproofing membrane was applied on top of the sub soil. The grounding conductor is stubbed up through the waterproofing membrane to be attached to the rail for the people mover. The waterproofing contractor wants to unbraid this 4/0 ground conductor to inject "Bituthene Deck Prep" between the conductors. We would then need to twist all of the individual conductors of the 4/0 cable togther for attachment to the rail.
Does anyone have any idea what affect this might have on the conductor. Is it a bad idea/
Does anyone have any idea what affect this might have on the conductor. Is it a bad idea/





RE: Grounding Conductor to Automated People Mover
TTFN
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RE: Grounding Conductor to Automated People Mover
But I would be concerned about how this junk might effect the terminations and also how it would behave on that fateful day when 30,000 A goes through one of those ground conductors.
Put yourself in the position of the electrical inspector - would you sign off on that installation?
David Castor
www.cvoes.com
RE: Grounding Conductor to Automated People Mover
Just seems like an all round bad idea. Part of my issue is I have a design team telling me this is what needs to be done to waterproof the cable. I agree this won't help much but the waterproofing installer is saying that unless we do this his warranty is void. Kind of a Catch 22 situation.
RE: Grounding Conductor to Automated People Mover
You're stuck in the middle, but I would not let some mud daubers dictate the electrical safety design.
You could request a variance from the local AHJ - then they can be the bad guys when they turn it down. It probably won't bother them a bit, and it gets you out of the middle.
If the AHJ accepts it (in writing), then all you can do is document your concerns and move on to the next problem.
David Castor
www.cvoes.com
RE: Grounding Conductor to Automated People Mover
t's unlikely that you'll be able to rewind it to the same pristine condition that the original machine winder produced, so there's a possibility that the overall resistance structure is changed. Moreover, there's a great likelihood that all this handling will increase the inter-strand resistance through dirt and oils, without even worrying about the goop contaminating things.
TTFN
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RE: Grounding Conductor to Automated People Mover
Suggest the contractor use a sealing substance with flow characteristics that will allow it to penetrate between the strands.
Option two: Break out the concrete and cast a Cad-Weld splice on each conductor. Alternately use a compression barrel that will compress the strands into a solid form. Re-pour the concrete. That will seal the conductors.
Option three; Slide some sort of compression collar down the cables to about two or three inches from the concrete. Compress well. Give this about a quarter turn with a pipe wrench to open the strands. Let the sealer have at it. Have the AHJ sign off on this method first.
Strongly suggest that the cables should have been sealed some way prior to the concrete being poured and any expense will be to the account of the sealing contractor..
Bill
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"Why not the best?"
Jimmy Carter
RE: Grounding Conductor to Automated People Mover
David Castor
www.cvoes.com
RE: Grounding Conductor to Automated People Mover
RE: Grounding Conductor to Automated People Mover