BEAMS AS A GEC

[ohmslaw]

I am inquiring about using a structural beam as a grounding electrode conductor. The base is connected to a ground grid, however, there are many "joints" in between the two points. can you find a code ref?

 

[ryan_618]

Re: BEAMS AS A GEC

I'm not sure where these "joints" that you speak of occur.

250.50 would probably apply and 250.104 might apply if I'm thinking of the right kind of "joint".

 

[ohmslaw]

Re: BEAMS AS A GEC

By joint I mean two beams (steal) have been connected together.

 

[ryan_618]

Re: BEAMS AS A GEC

Good. I left my code book at work today, but I know that 250.50 applies, and I'm pretty sure there was a change in the 2002 to section 250.104 that addresses bonding around joints in structural steel.

 

[dereckbc]

Re: BEAMS AS A GEC

The code sections are 250.50 and 250.52(A)(2). If the building steel is effectively grounded as you describe, it becomes a electrode.

The joints are typically bolted, riveted, or welded. Each method is effective to make an electrical bond IMO.

 

[dereckbc]

Re: BEAMS AS A GEC

Originally posted by ryan_618:
Good. I left my code book at work today, but I know that 250.50 applies, and I'm pretty sure there was a change in the 2002 to section 250.104 that addresses bonding around joints in structural steel.

Ryan, 250.104(C) refers to structural steel that is not intentionally grounded and may become energized. What he is describing IMO is that the building steel has been intentionally bonded to a grid, making it part of the electrode system.

 

[ryan_618]

Re: BEAMS AS A GEC

Thanks Dereck. I should probably just shut up when I don't have my NEC here.

 

[dereckbc]

Re: BEAMS AS A GEC

Ryan, I know you recently became an inspector, congrats.

I have had a few debates with inspectors in Salt Lake, Chicago, and Tampa about steel beams being effectively bonded. They wanted a bonding strap installed. I contend the weld , bolts or rivets are effective.

What is your oppinion?

 

[ryan_618]

Re: BEAMS AS A GEC

I would agree with you on that. Again, I don't have it in front of me, but it seems like that change addressed physical braeks in the structural steel, such as those that occur at a loading dock that might have its own structural steel. I think the welds/rivets/bolts are fine.

BTW: Thanks for the congrats!!! Actually, I've been an inspector for a couple of years, but I just passed my electrical plan review test (first in Utah to do so )

 

[big jim]

Re: BEAMS AS A GEC

I would say that any AHJ that wants to bond a structural steel joint has absoutely no comprehension of the design and installation processes. I sure hope he's not a multi-trade inspector.

 

[pierre]

Re: BEAMS AS A GEC

I wonder if the inspector who does not accept bolted steel beams as acceptable, would he accept bolted bus?

Pierre
P.S.
It sure is windy this morning, I wonder how long we will have power today before limbs start knocking it out?

 

[vanwalker]

Re: BEAMS AS A GEC

still learning?? why would you use building steel as a grounding electrode conductor(gec)THANKS GEO

 

[ryan_618]

Re: BEAMS AS A GEC

Originally posted by vanwalker:
still learning?? why would you use building steel as a grounding electrode conductor(gec)THANKS GEO

You wouldn't use it as a grounding electrode conductor, but you would use it as a grounding electrode. You are required to do so if it is available and is effectivley grounded.