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Thread: Using structural steel as a sleeve for MC

  1. #1
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    Using structural steel as a sleeve for MC

    At a recent project I noticed that the Electrician drilled a hole in the structural steel column above the drop cieling and sleeved M.C. through. They the installed a Wire mold box and installed the MC into the back of it. It is my understanding that you can not degrade the structural integrity of a building. We usually install a half inch E.M.T. on the structural column to a four inch square deep for the receptacle.
    Is the allowable to drill into the sructural steel or would it compromise the integrity?
    Thank you for your time and effort.

    Justin W.
    still commited to non violence and passive resistance

  2. #2
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    Re: Using structural steel as a sleeve for MC

    Originally posted by justinjwalecka:
    Is the allowable to drill into the sructural steel or would it compromise the integrity?

    Justin W.
    That would depend on the size of the hole compared to the size of the column.

    In general I have never heard of an issue in drilling a 1" or smaller hole in building column.

    Most tube type columns I run into are larger than 8" x 8" so a 1" hole is not a big deal.

  3. #3
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    Re: Using structural steel as a sleeve for MC

    I agree with Bob. The strength in the column as far as I understand it is in the corners. Drilling a hole in the center does not weaken it considerably. There are people/books that know what you can do, consulting with them is wise.

    I've seen 8" x 8" canopy columns at gas stations with 3.5" holes drilled (actually burned) at grade level and below grade level for drains for the canopy.
    Lou (wannabe economist)

    If you relentlessly pursue perfection, you will eventually catch excellence.

  4. #4
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    Re: Using structural steel as a sleeve for MC

    The safe bet is to contact the Architect or Engineer who designed the work (if it is a new job) and ask them what they think.

  5. #5
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    Re: Using structural steel as a sleeve for MC

    Justin, you could even be talking about me. I've done that exact same thing from time to time in central PA. I small round hole in a box column is no different than if that column was a lattice column. That little 7/8" hole in the top and bottom isn't going to hurt a thing.

  6. #6
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    Re: Using structural steel as a sleeve for MC

    Iwire , Hardworkingstiff, Pierre, and Mdshunk thank you for your feedback. The installation of the M.C. through the column seemed an efficient way of feeding the outlet.

    Justin W.
    still commited to non violence and passive resistance

  7. #7
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    Re: Using structural steel as a sleeve for MC

    I don`t want to insult you but in your profile you listed as a journeyamn.But in this post you reffered to the electrician on the job
    Are you the ec or the gc ??????

  8. #8
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    Re: Using structural steel as a sleeve for MC

    Allenwayne no insult taken. I'm a journeyman Electrician working at a Lowes in New Hampshire. The Target next to our project is where I saw the issue. I enjoy observing other contractors installations. Thank you for your time.

    Justin W.
    still commited to non violence and passive resistance

  9. #9
    Join Date
    Aug 2005
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    22

    Re: Using structural steel as a sleeve for MC

    Before I would drill any hole in any structural member of a building, it might be wise to do what was suggested before- contact the PE who designed the structure. Or do the analysis yourself to ensure all the moments, shears, compressions, tensions, torques etc are still handled by the reduction in capacity of the column that was drilled to put a wire through.

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