Acceptable clamp for connection to building steel.

[Mike Burch]

What would an acceptable connection method be for connecting the conductor from the neutral of a seperately derived system (transformer secondary) to the building steel? Is a galvanized beam clamp ok? Or should it be another alloy?
Thanks in advance. Mike Apache Junction, Arizona

 

[iwire]

In my opinion a standard beam clamp is a violation of 250.8. You may be able to find a listed grounding clamp from Blackburn.

We either drill and tap the beam, or drill it and use a nut and bolt, or cad weld it. We also use a wire wheel or a grinder to clean up the steel before bolting the lug on.

Building steel is 'mild steel' so it drills and taps pretty easily with a sharp bit.

 

[infinity]

I agree with Bob, although I see beam clamps used this way quite often. There are listed products that can be use to avoid drilling the beam. A standard 1/4" or 3/8" beam clamp with a lug attached isn't one of them. We always use one of these on the end of the conduit, drilled and through bolted to the beam:

 

[Mike Burch]

In my opinion a standard beam clamp is a violation of 250.8. You may be able to find a listed grounding clamp from Blackburn.

We either drill and tap the beam, or drill it and use a nut and bolt, or cad weld it. We also use a wire wheel or a grinder to clean up the steel before bolting the lug on.

Building steel is 'mild steel' so it drills and taps pretty easily with a sharp bit.

I see, I was under the impression that any hole drilled through a structural beam seriously weakens it (the beam) and should be avoided. I will have to look into this further. Thank you for the reply. Mike

 

[infinity]

I see, I was under the impression that any hole drilled through a structural beam seriously weakens it (the beam) and should be avoided. I will have to look into this further. Thank you for the reply. Mike

IMO a 1/4" or 3/8" hole will not seriously weaken a beam. This is a standard operation for GEC attachment.

 

[petersonra]

beam clamps seem to be a common attachment method, but I have never especially liked it.