Wrapping Beams

horsegoer

Senior Member
Location
NJ
So we have a long run of a few conduits with no other routing available. We have about 20 of these beams we have to wrap that are in the run. I suggested running the conduits of threaded rod at a height right below the bottom of the beam but they want us to run tight to the slab so we have to wrap the beams. No other easier/cheaper way to do this besides wrapping with LB's? It's 1" EMT conduit. Thanks.
 

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infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
You've outlined the two ways to do this: 1) run straight across at a height right under the beam or 2) go up and across and down with conduit bodies like in your graphic. Since they're telling you to use method 2) it doesn't seem like you have much of a choice. One up and down method would involve using offsets instead of the LB's.
 

PaulMmn

Senior Member
Location
Union, KY, USA
Looks like a lot of apprentice work to bend the conduits and cut the parts for the bottom of the beams.

What's the total length of the run (both straight line and 'wrapped?'

Are the beams evenly spaced?
 

PaulMmn

Senior Member
Location
Union, KY, USA
You've outlined the two ways to do this: 1) run straight across at a height right under the beam or 2) go up and across and down with conduit bodies like in your graphic. Since they're telling you to use method 2) it doesn't seem like you have much of a choice. One up and down method would involve using offsets instead of the LB's.
Wouldn't offsets require a lot longer pull? What can you get-- maybe one beam before you have to have a pull-point?
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Wouldn't offsets require a lot longer pull? What can you get-- maybe one beam before you have to have a pull-point?
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.
 

horsegoer

Senior Member
Location
NJ
Looks like a lot of apprentice work to bend the conduits and cut the parts for the bottom of the beams.

What's the total length of the run (both straight line and 'wrapped?'

Are the beams evenly spaced?
Beams are evenly spaced. Run is about 400'
 

horsegoer

Senior Member
Location
NJ
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.
Aren't the conduit bodies a pull point and reset the 360?
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Aren't the conduit bodies a pull point and reset the 360?
Yes but they increase labor over using offsets. Even pull boxes are easier that LBs be cause you can pull straight through
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.
 

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
What about some sort of wireway for the run on the bottom of the beam. As drawn you need to pull the wire down from one conduit, fish it in and pull through the short section on the bottom of the beam, and then fish it through the long run to the next beam. If you had something that was like a long doubled ended LB with a single cover, then you eliminate one of those pulling operations.

Also you say the customer wants the conduit tight to the beam. But if the conduit can be one bend radius away from the beam on one side, then you could have a 90 there and eliminate 1 pull operation per beam.
 
What about some sort of wireway for the run on the bottom of the beam.
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.
 

flashlight

Senior Member
Location
NY, NY
"What about some sort of wireway for the run on the bottom of the beam."

I agree. Such as 4x4 trough, or wiremold 400. Single cover, no pipe in between to muck around with during pull.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
With a 400' run, then going to the side a bit should be a reasonable option.

How far is it to the nearest wall or other vertical surface, or row of columns?
 

augie47

Moderator
Staff member
Location
Tennessee
The raceway was what I was thinking about when I inquired about dimensions. If the conduits are close to each other I think it would definitely be worth considering.
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Sounds to me like the designer wants the conduit out of the way to make room for other work like duct work, piping, etc. so they need to be close to the ceiling and the beams.
 
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