mstrlucky74
Senior Member
- Location
- NJ
What is this standard radius on an 90 degree elbow, 36"? Thanks
Elbow radius
- Thread starter mstrlucky74
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cadpoint
Senior Member
- Location
- Durham, NC
What type of material, and what size of pipe?
- Location
- Illinois
- Occupation
- retired electrician
See Chapter 9, Table 2.
mstrlucky74
Senior Member
- Location
- NJ
Emt or rgs
Want to know the difference between a standard elbow and a sweep elbow. I'm thinking it's the radius.
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- Occupation
- Licensed Electrician
You are correct. Sweeps have a bigger radius.
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
And a PVC plumbing elbow has an even tighter radius, with a "compact" elbow being tighter still.
- Occupation
- Licensed Electrician
Funny you should mention that since I worked on a project in my fair city where some plumbing elbows were used in a sub-division. Pavement and side walks got dug up on several blocks before the problem 90's were discovered.
mstrlucky74
Senior Member
- Location
- NJ
- Location
- Illinois
- Occupation
- retired electrician
Larger than what is shown in Chapter 9, Table 2.
While the assumption is that the use of the larger radius bends reduces the required pulling force, none of the cable calculation formulas I have seen show that. The use of the larger radius does reduce the sidewall pressure that can damage the conductor insulation. On most pulls with bends the sidewall pressure and not the pulling tension is the limiting factor for the pull.
jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
I thought the limiting factor was the size of the apprentices pulling the rope.....
mstrlucky74
Senior Member
- Location
- NJ
What determine when you would use a large sweep/radius elbow?
- Location
- Illinois
- Occupation
- retired electrician
The job design specs, or a pulling calculation that shows too much sidewall pressure with a standard radius elbow. Sidewall pressure is the crushing force between the conductor and the inside radius of the elbow when you are pulling the conductors. It is a function of the pulling tension and the radius of the elbow.
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