I Beam in residential basement

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pete m.

pete m.

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Would anyone consider a steel I-Beam supporting wooden floor joists in a residential (or commercial) setting as "structural metal interconnected to form a metal building frame"?

"(C) Structural Metal Exposed structural metal that is interconnected to form a metal building frame and is not intentionally grounded and is likely to become energized shall be bonded to the service equipment enclosure, the grounded conductor at the service, the grounding electrode conductor where of sufficient size, or the one or more grounding electrodes used. The bonding jumper(s) shall be sized in accordance with Table 250.66 and installed in accordance with 250.64(A), (B), and (E). The points of attachment of the bonding jumper(s) shall be accessible." (taken from 250.104(c)).

If you would, then would you also allow this I-Beam to be used as a grounding electrode conductor in accordance with 250.52(a)(2)?

There is an electrical engineer that has asked another inspector why they are not enforcing the NEC with regard to this issue. NEC references are taken from the 2005 edition.

Opinions?

Thanks, Pete
 
Re: I Beam in residential basement

I would not. An I-Beam does not comprise a "building frame." It is but a member of the building frame, the rest of which is not metal. Also, unless you are using the I-Beam as a wireway (e.g., running conductors alongside or under the beam and somehow attaching them to the beam), then I wouldn't describe is as "likely to become energized."
 
Re: I Beam in residential basement

It is hard to imagine a single isolated I-Beam being considered a frame. It is certainly not "interconnected" to anything.

However, if there were to be several of them that were connected together in some way, that migth well be a different story.
 
Re: I Beam in residential basement

Originally posted by petersonra:


However, if there were to be several of them that were connected together in some way, that migth well be a different story.
Click to expand...
It would have to be more than just a few peices of steel in my opinion.
 
Re: I Beam in residential basement

I have been working in wineries lately. CA central coast wineries are growing exponentially. I have been hooking up new fermentation tanks. The only power on the stainless steel tanks is 24 VAC for the refrigeration control system. I bond the tank with the drain wire from the 18/2 which feeds the temperature control module. It seems to me that these huge steel tanks should have serious bond wires. They have no bond wires at all. Before I connected any of my wires, I metered from each tank to a hot wire on my drop light. My Fluke always registered 115+ volts to ground. The only ground I could see was the six legs touching the concrete. When I performed the test, the concrete floor was wet. They were pumping wine out of existing tanks and hosing down the floors.

Is contact with the concrete floor an adequate bond? Why did my Fluke register 115 VAC ?

In order to pump wine in or out of the tanks, we use cord connected 480 VAC motors mounted on four wheel carriages which resemble push mowers. If one of these hoses connected to the fermentation tanks had a fault, couldn't someone fry. Yes the hoses are non-metallic, but couldn't the tank somehow become energized? We do work in most of the wineries around here and they are all the same.
 
Re: I Beam in residential basement

The structural steel not only has to be interconnected to form a frame, but would have to be exposed.
Boxing in the steel is pretty common, although there are some unfinished basements still ;)

I agree with the others in that 1 piece of steel does not make an interconnected frame.
 
Re: I Beam in residential basement

Since it is in a basement, it probably wouldn't hurt any to bond it, but it should not be required. Murphy's law and all, somehow, sometime this thing may get accidentially energized and present a touch hazard. I ran across a gutter downspout once that had 120 volts to ground on it.
 
Re: I Beam in residential basement

I have a large metal tool chest in my basement.

Is that likely to be energized?

Should I bond it?

What size bonding conductor would I use? :p
 
Re: I Beam in residential basement

Originally posted by iwire:
I have a large metal tool chest in my basement.

Is that likely to be energized?

Should I bond it?

What size bonding conductor would I use? :p
Click to expand...
It might well be "likely to be energized". Many craftsmen have electrical outlets of various types installed on their tool carts. These typically are bonded through the power cord that plugs into a convenient outlet. The size is determined by the size of the BC OCPD.
 
Re: I Beam in residential basement

Just remember there is a big difference in the meaning of "likely" and "possibly".

It is more likely that a 16d nail will be driven into a piece of NM in a wall, than an isolated support beam will become energized.

Get out your Funk and Wagnals, well actually your Websters.

Likely: Possessing characteristics that make something probable {probable: with considerable certainty; without much doubt}

Possibly: Of uncertain likelihood
 
Re: I Beam in residential basement

I have always considered the phrase "likely to become energized" as really meaning "it could happen, even if the chance is remote". That seems to be the way it is typically interpreted.
 
Re: I Beam in residential basement

Originally posted by iwire: I have a large metal tool chest in my basement. Is that likely to be energized?
Click to expand...
That depends. Do you keep any batteries or battery-operated equipment inside it? :D
 
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