High Tension Lines?

[SteelPE]

This has to be one of the dumbest questions ever.

I have been asked to put a proposal together on a large warehouse (370,0000 square feet) in the middle of nowhere. The only issue with the middle of nowhere is that there are some high tension lines that run parallel to our proposed building (at least that is what I picked up from the civil drawings. The proposed building is a steel framed building that will be built 10' away from the line easement.

I am wondering if there would need to be anything done to "ground" the building? I know that grounding is required for reinforcing in a transformer pad. I also remember from my osha training to not park under high tension lines (I remember that a bit from my rudimentary physics classes too).

 

[phamENG]

All the projects I've worked on, lighting protection, grounding, etc. has been in the purview of the EE. I will admit that I haven't done one this close to high voltage transmission lines, though.

I have put notes on drawings to warn erectors (who may or may not receive the civil drawings when asked for initial bid) that there are lines nearby that may limit crane/equipment choices.

 

[dik]

Good idea... I've not done that, but I have added information on a couple of projects near airports about encroaching into airspace.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[dauwerda]

If you are outside of the easement there shouldn't be anything special to be concerned about with the building itself. It definitely is a consideration for crane (and man lift, fork lift, etc.) operation during construction (as phamENG noted).

Note, when ground electrodes are tied into the rebar on the foundations, it is not to ground the foundation per se. It is using the foundation as a ground (ufer ground), this can be used to replace the need of driving more ground rods that tie into the ground grid. In other words, tying the foundations into the ground grid helps the overall performance of the ground grid, it does not increase the amount of grounding electrodes needed.

 

[vmjr24]

Standard practice is to make sure the line has proper electrical clearance to anything that gets built right on the edge of the easement. The line should offset from the edge of easement at a minimum distance of the blowout distance of the line under wind plus the electrical clearance. Plus your building will have 10 feet of extra clearance on top of that since it's not right on top of the easement line. The National Electrical Safety Code (NESC) likely has your answer for that electrical clearance if you can find it. Might be best just to get the utility who operate the line involved so they can verify everything for you.

 

[JLNJ]

If there is sensitive equipment inside the warehouse, someone might need to look into the electrical fields generated by the lines.

We did a dorm on a university campus where there were 270kV lines nearby. It was surprising how far out from the lines the fields extended. There was some concern about the kids' health and the field's effect on the kids' computers. We looked at burying the cables, but that was crazy money. In the end we moved the buildings a little and called it good.

That said, I have no idea what kind of equipment could be affected.

 

[SlideRuleEra]

...steel framed building that will be built 10' away from the line easement.

What is the power line voltage, what is the length of the building parallel to the power line, how wide is the easement, and how far will the building be from the closest conductor? That will determine what, if anything, to do.

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