Wrapping Beams

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How wide are the beams?

It may be simpler to come into the back of a wide pull box than use multiple LB's and nipples..
 
Is that isometric diagram a real diagram of the actual installation? If so, that massive girder is holding up smaller girders that would provide a straight-thru path for conduit.
 
infinity said:
If you use 30° offsets each beam would be 120° of bend, 360/120=3 so after every third beam you would need a pull point. Use 45° offsets and you would need a pull point after every second beam. Multiple pull points like using many LB's make wire pulling more expensive.
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So in a siutation like the attached. Just talking about one of pipes which id 3/4" emt with 8#10'w. What or at what points would the setup/breakdown of equipment be for a wire pull with so many LB's?
 

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infinity said:
Yes as MK stated and that was my point. A million LB's will make pulling wire much more expensive. With a straight-thru pull box every 360° you might even be able to pull through a few saving even more in labor cost.
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As I stated above I understand what your saying but not the layout of the boxes in lieu of the LB's. Still need to get around the beam.
 
electrofelon said:
I was thinking the exact same thing. I have used used small 4x4" wireways before, not sure how short they come off hand.

I dont really like the LB idea. Although it may look the best, LB's are both expensive and generally a pia.

Ive done a lot of work in old mills with big timbers and we did offsets to get under all the beams, but this was mostly lighting and fire alarm so it seemed like we had boxes so frequently for devices that we never needed pull boxes.
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Willie and felon, thank you very much. I can't picture what mean. So conduit would be run tight to slab then drop down( by the beam) and connect directly into a wireway under the beam, then exit the other end of the wireway with conduit back up to the slab?
 
horsegoer said:
Willie and felon, thank you very much. I can't picture what mean. So conduit would be run tight to slab then drop down( by the beam) and connect directly into a wireway under the beam, then exit the other end of the wireway with conduit back up to the slab?
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That is what I was thinking as a possibility. If you want the conduit to drop down flush with the beam, you can't have a bend to transition to the bottom of the beam. So you could have 2 LBs at the base of the beam (for the conduit coming down and going up on the other side). Between the two you would need a short bit of conduit.

The problem is that you can't pull _through_ an LB, so the above approach requires 2 pulling operations per beam.

If you replace the pair of LBs with a wireway that goes across the bottom of the beam, then you can pull wire from beam 1 to beam 2, feed the wire into the 'up' conduit and pull to beam 3, and then snap the lid on to the wireway. 1 pull.

-Jon
 
To me, wrapping every beam for 400' is ridiculous. I repeat my previous suggestion to look for the nearest vertical surface or row of columns. Those beams can't be so long that an alternative to wrapping is out of the question.
 
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