boots 211

I have a customer that wants to ground 4 grain bins on his farm. Has anyone ever done this before? Did you just attach a lug to bin, then wire to ground rod? If so how did you attach then lugs?

oldtimer

Could you not bolt a lug to each grain bin, then daisy chain to a ground rod?

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OK, so what's the speed of dark?

Steven Wright

John Valdes

Yes. Good question. I have always been taught to ground to the system grounding/bonding structure. Not to indiscriminately drive rods or install other electrodes.
But then again this is a subject of its own. I will be listening.

Tom45acp

You might ask your customer why he wants the grain bins grounded. If it is for preventing explosions from static electricity, then you should purchase NFPA 77 & go from there. If it is for lightning protection, IMO, your customer should be referred to someone that specializes in lightning protection systems.

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Sometimes I wonder whether the world is being run by smart people who are putting us on, or by imbeciles who really mean it.

nitro71

The grain bins are probably bolted to large bolts sunk deep in concrete. If that's the case they are already grounded pretty good. Kinda like light poles. Is this an engineering spec or?

varmit

The grain bins are probably bolted to large bolts sunk deep in concrete. If that's the case they are already grounded pretty good. Kinda like light poles. Is this an engineering spec or?

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I would tend to agree with the above statement, but the bins are probably not bonded to each other. Often, the augers and conveyors that transfer grain to or from the bins, are not connected mechanically to the bins. This can create an arc potential due to the static buildup when transferring dry, dusty grain. Grain dust is VERY flammable.

Lightning protection is a whole different world with almost limitless variables, but there is usually a generic, to your area, method of lightning protection that most locations use with acceptable results.

boots 211

Actully the way these bins are put together is to start with top and add side then lifting it up with cable jacks and then add more side, then the final section has mounting angle that are anchored with bolts and lag anchors. So they are not really grounded well. I thought about using lugs on the anchor bolts but they have to be too big to accept a piece of # 6 copper.

amptech

On new construction I always have a section on rebar stubbed out at each concrete bin base for a Ufer. If there are multiple bins and grain will be transferred between them they are all bonded together with 4/0 cu.
If it is an existing bin/bins I drive 4 rods 90 degrees apart around the bin and connect each rod to the bin with #4 solid cu using a lug bolted to a base bolt at each point. Then bond the bins together with 4/0 cu. I have had customers request a ground ring of #4 bare solid cu trenched 18" deep all the way around the bin with #4 cad welded at 4 points and lugged to the bin at the 4 points. Either way should keep the bins at the same potential to avoid static discharge when transferring grain.

RIVETER

Not that you don't know, but there is a difference between grounding grain bins and bonding them. If it is all concrete...no bonding.