# Grounding an elevator leg?



## Funkadelicfred (Jan 30, 2019)

Working on a 150' elevator leg and everything is good but since it's so tall (and not engineered) would it be a good idea to bond the entire system? This isn't something we've ever done before and I'm wondering if any of you farm/ag guys or anyone working on really tall metal structures have done anything like this or just don't bother?


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## glen1971 (Oct 10, 2012)

Everything I've done that is tall has been bonded to a ground system of many different kinds from a single (or more) 2/0 to a larger grid, rods in four corners around an area and a 2/0 to each vessel/structure, 3 - 50' ground rods and 750 mcm to a 75' radio tower, 3 - 10' rods around the base with a 2/0 tail from each to the tower and all of it connected with a 2/0 back to the main grid, etc.. I've done mostly oil and gas though and all north of the 49th, so take it as you will..


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## gpop (May 14, 2018)

If it has a motor and the frame of the motor is bolted to metal then you have a ground path. I would be tempted to bond it in the hope that lightning would go that direction rather than chasing the motor ground but its a dark art predicting what lighting will do.


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## Forge Boyz (Nov 7, 2014)

How would you go about bonding it? The whole system is tied together with the piping which should give it a good solid connection. I don't know that the leg/bins have a solid connection to steel in the ground but it never seemed to matter on any system I've ever worked on.
If the leg has cable supports they are probably tied off to a large chunk of steel and concrete in the ground anyway. It's hard to beat that with a ground rod. 

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## joe-nwt (Mar 28, 2019)

Radio towers aren't grounded in case they get hit by lightning, they are grounded for WHEN they are hit by lightning.


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## Cow (Jan 16, 2008)

The grain system we're working on now, we treated the framework structure and legs as building steel and ran a 3/0 CU over to it from the switchboard.


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## 460 Delta (May 9, 2018)

If the foundation leg bolts are attached to the rebar like people generally do, wouldn’t you have a large Ufer ground system?


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## Cow (Jan 16, 2008)

460 Delta said:


> If the foundation leg bolts are attached to the rebar like people generally do, wouldn’t you have a large Ufer ground system?



A lot of times I see the carpenters suspending the bolt pack over the concrete form with a plywood template. Similar to how we do light pole bases.


The j-bolts don't even contact the rebar.


It's hard to know unless you see it poured.


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## glen1971 (Oct 10, 2012)

Forge Boyz said:


> How would you go about bonding it? The whole system is tied together with the piping which should give it a good solid connection. I don't know that the leg/bins have a solid connection to steel in the ground but it never seemed to matter on any system I've ever worked on.
> If the leg has cable supports they are probably tied off to a large chunk of steel and concrete in the ground anyway. It's hard to beat that with a ground rod.
> 
> Sent from my SM-G970U1 using Tapatalk


Use a KC26 servit post, cad weld, one hole crimp lug and a double nutted bolt and a properly sleeved/protected bonding conductor, and connect to your switchboard ground. And glyptal the connection when you're done.
If it's a visible connection it is easy to test and inspect, should the need ever arise.
Also FWIW, I never rely on piping to ensure a proper bond. If someone had the piping apart, you lose your bond.


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## splatz (May 23, 2015)

460 Delta said:


> If the foundation leg bolts are attached to the rebar like people generally do, wouldn’t you have a large Ufer ground system?


It's not necessarily an ufer but according to code it's a grounding electrode if conditions are met. The problem is like @Cow says you can't really figure that out once it's built. 

For lightning protection, I think I'd want the ground ring out of these options. 



> 250.52(A)(2) Metal Frame of the Building or Structure. The metal
> frame of the building or structure that is connected to the
> earth by any of the following methods:
> *(1) 3.0 m (10 ft) or more of a single structural metal member in direct contact with the earth or encased in concrete that is in direct contact with the earth*
> ...


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