Building Steel?

[stingerleg]

What does it take for a steel beam to qualify as building steel for a seperately derived system. And how do you prove it.

 

[RUWired]

What does it take for a steel beam to qualify as building steel for a seperately derived system.

250.52 Grounding Electrodes
(2) Metal Frame of the Building or Structure The metal frame of the building or structure, where any of the following methods are used to make an earth connection:
(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
(2) The structural metal frame is bonded to one or more of the grounding electrodes as defined in 250.52(A)(1), (A)(3), or (A)(4)
(3) The structural metal frame is bonded to one or more of the grounding electrodes as defined in 250.52(A)(5) or (A)(6) that comply with 250.56, or
(4) Other approved means of establishing a connection to earth.

I suppose testing would prove it.

 

[brian john]

If you have a known electrode and it has been tested to meet job specs (if any exist) you can use a Earth Ground Resistance Tester and perform a 2-point test. If no electrode exist a properly conducted 3-point test would be required. In lieu of this if there is an existing service you could utilize a clamp on ground tester, but this would require setting up some temporary wiring.


http://www.aemc.com/

http://www.aemc.com/techinfo/index.asp