Steel building ground

[Tscott]

Ok here is another question for you professionals out there. What kind of grounding will be required for my steel framed steel skinned building. Will a standard double ground rod arrangement be satisfactory? I read in the NEC that metal buildings may need to have a "grounding ring" installed. This is essentially a copper loop buried 3' into the earth around the entire building with ground rods placed at the corners.

Tom

 

[walrus]

Ok here is another question for you professionals out there. What kind of grounding will be required for my steel framed steel skinned building. Will a standard double ground rod arrangement be satisfactory? I read in the NEC that metal buildings may need to have a "grounding ring" installed. This is essentially a copper loop buried 3' into the earth around the entire building with ground rods placed at the corners.

Tom

The building steel needs to be bonded. What code cycle are you on? If 2008 you need a concrete encased electrode, rebar in other words. I've never heard of a bonding ring for a steel building

 

[Tscott]

The building steel needs to be bonded. What code cycle are you on? If 2008 you need a concrete encased electrode, rebar in other words. I've never heard of a bonding ring for a steel building

Before I poured the pad, the inspector told me I did not have to bond to the rebar as long as I bonded the building once complete.

I believe we are on 2008 code here in Florida.

Tom

 

[W-Cummins]

I installed a grounding system on my building, probably overkill but it's the way I wanted it. Anyway I used an Ufer ground with the re-bar in my footing, and also used the 2, 8' ground rods. Strange thing is the Ufer ground only requires a #4 copper wire to it, my grounding conductor for my panel required #00 copper. It seemed to be a waste to run that over to the little #4 for the ufer ground so I used the #00 stuff to the rods and then on to the Ufer where I crimped it to the smaller stuff. I also used the #00 to bond the steel building frame to the system. I used a 1/4" X 1.5" X 6" plate to attach the bonding conductor to the steel and bolted it to a girt attachment at the main frame, then I spot welded the nuts so it could not be removed ( required so I could bury it in the wall ). All the connections were hydraulically crimped to the rods, re-bar, taps and the terminal that attached to the bonding "plate". William....

 

[walrus]

Before I poured the pad, the inspector told me I did not have to bond to the rebar as long as I bonded the building once complete.

I believe we are on 2008 code here in Florida.

Tom

Are the anchor bolts in the concrete connected to the rebar? I guess it doesn't matter if he said you don't need to worry about it?

 

[Tscott]

Are the anchor bolts in the concrete connected to the rebar? I guess it doesn't matter if he said you don't need to worry about it?

No, the bolts were not tied to the rebar.

I am slowing learning that the local inspector is not the brightest Crayon in the box. I am afraid he will still give me a problem about it even though he told me how to do it. I think I will proceed as though it was a residential type building. I will bond to the steel structure near the panel, and then drive my 2 ground rods. Then I will cross my fingers and hope he does not baulk.

What is the preferred method to attach a grounding conductor to the steel of the frame? Perhaps a clamping method as described by W-Cummins or maybe a cad weld type connection?

Tom

 

[W-Cummins]

No, the bolts were not tied to the rebar.

What is the preferred method to attach a grounding conductor to the steel of the frame? Perhaps a clamping method as described by W-Cummins or maybe a cad weld type connection?

Tom

You can bolt the crimped on end to the steel as long as you can get to it. The reason I did it the way I did was to allow it to be used in an non accessible location ( it's under the inside wall that supports my second floor). That required the irreversible connection, and I came up with the solution that the inspector liked ( he looked at it and said yep that's not coming off William...

 

[sberry]

I think it needs a heavy bond wire, like a 2 or something for 200A, bolt a copper lug to the building.