Page 4 of 5 FirstFirst ... 2345 LastLast
Results 31 to 40 of 45

Thread: conduit bend radius

  1. #31
    Join Date
    Jul 2003
    Location
    MA
    Posts
    1,579
    Quote Originally Posted by don_resqcapt19 View Post
    I know that the radius for 1/2" conduit is very tight on those benders and almost always bend the 1/2" conduit in the 3/4" shoe, but I don't think that the radius is illegal. Chapter9, Table 2 permits a radius of 4" for 1/2" conduit.
    The Greenlee 1800 bender has a bend radius on the 1/2" shoe of 2-5/8".
    Table 2 in Chapter 9 calls for a 4" radius in 1/2".

    The 1/2" shoe is only good for making kicks and offsets. If you make a 90º bend, it would be a violation.
    I have always used the 3/4" shoe when using this bender.

    Last edited by tkb; 09-14-11 at 09:24 AM.
    Tim
    Master Electrician
    New England
    Yesterday's Technology at Tomorrow's Prices

    Answers based on 2011 NEC

  2. #32
    Join Date
    Feb 2003
    Location
    Illinois
    Posts
    18,582
    Quote Originally Posted by tkb View Post
    The Greenlee 1800 bender has a bend radius on the 1/2" shoe of 2-5/8".
    Table 2 in Chapter 9 calls for a 4" radius in 1/2".

    The 1/2" shoe is only good for making kicks and offsets. If you make a 90º bend, it would be a violation.
    I have always used the 3/4" shoe when using this bender.

    Tim,
    I did not know that. Thanks.
    344.24 Bends — How Made. Bends of RMC shall be so made that the conduit will not be damaged and so that the internal diameter of the conduit will not be effectively reduced. The radius of the curve of any field bend to the centerline of the conduit shall not be less than indicated in Table 2, Chapter 9.

    I assumed that since the code rule applies to all bends no matter how many degrees are in the bend that the bender would comply with the code rule.
    I do see that the instructions for that bender say:
    * To meet electrical code, bend 1/2" diameter conduit in the 3/4" position to produce a bend with a radius greater than 4".
    Don, Illinois
    "It is the first responsibility of every citizen to question authority." B Franklin

  3. #33
    Join Date
    Jul 2003
    Location
    MA
    Posts
    1,579
    Quote Originally Posted by don_resqcapt19 View Post
    Tim,
    I did not know that. Thanks.

    I assumed that since the code rule applies to all bends no matter how many degrees are in the bend that the bender would comply with the code rule.
    I do see that the instructions for that bender say:
    I don't know why they manufacture this bender like this but it has been this way forever.
    I will admit that I have used the 1/2" shoe a bunch of times because of space limitations at terminations. Kinda like those explosion proof elbows that look like plumbing 90's.

    I'm not sure if those 90's are ok to use per code or listing but I remember that they could only be used at terminations. I may be wrong though.
    Last edited by tkb; 09-14-11 at 01:41 PM.
    Tim
    Master Electrician
    New England
    Yesterday's Technology at Tomorrow's Prices

    Answers based on 2011 NEC

  4. #34
    Join Date
    Aug 2009
    Location
    Central NC
    Posts
    1,466
    Quote Originally Posted by tkb View Post
    I don't know why they manufacture this bender like this but it has been this way forever.
    I will admit that I have used the 1/2" shoe a bunch of times because of space limitations at terminations. Kinda like those explosion proof elbows that look like plumbing 90's.

    I'm not sure if those 90's are ok to use per code or listing but I remember that they could only be used at terminations. I may be wrong though.
    I think sharp 90's used to be allowed for a short termination where wire was pushed by hand, say from an LB to a machine, or J box to machine. But that is not the usual 90 either.

    Never made sense to me for a mfr to make a machine that way. Someone may forget to remind the helper or someone used to hand benders may be using a Chicago bender for first time, etc. Instruction booklets are usually the first thing to get lost too. I came on a job once & saw 1/2 90's in the runs, asked foreman if he knew of the short radius. He looked at me funny, like "don't challenge me already". He said, "I thought they didn't look right but I wouldn't think of a bending machine doing illegal bends". From then on, he used the 3/4 shoe for 1/2. Once we know that, we work around it. Before that, we are set up for problems.
    Yes, I'll be happy to do a first class job for less than anyone else and take a dollar a week for 10 years.

  5. #35
    Join Date
    Aug 2009
    Location
    Central NC
    Posts
    1,466
    Watch for this too. It doesn't keep the tail of the pipe level. We had one with no protractor built in & had to use levels. Had to shim up the rear of the bender to level it out. Check that out if you do critical bends on that type of bender.

    Best bender I worked with was the Greenlee Hurricane bender. Hydraulic, with protractor & notes telling how much to allow for spring back. Was accurate to 1 or 2 degrees, quick & easy to use. Had shoes for EMT & rigid up to 2 inch. Not sure if you could get larger shoes. I never used the bigger hydraulic benders much, helped with them a little. Nearly every job had 1 or 2 small crews that did all those bends. Someone really had to know those benders, with having to move pins & inserts for all different angles & sizes. I just never had the chance to use them much. I wouldn't try to use 1 today without help. Too easy to damage something or waste expensive conduit.
    Yes, I'll be happy to do a first class job for less than anyone else and take a dollar a week for 10 years.

  6. #36
    Join Date
    Aug 2007
    Posts
    457
    Quote Originally Posted by jmellc View Post
    I worked 1 job where we ran conduits for fiber optics. They had to be wide radius, as the cable could not take sharp bends.
    The first fiber optic job I worked on was a project for IBM back in the 90's. We ran 1-1/2" EMT, no bends larger than 22 1/2º and 24" x 24" x 6" pull boxes where ever you had to turn 90º. Along with many other restrictions, it was a challenging job finding a path above the existing drop ceilings.

  7. #37
    Join Date
    Aug 2011
    Location
    south texas
    Posts
    284
    to the original post, refer to Table 2 in chapter 9, of the 2008 NEC. page 671

  8. #38
    Join Date
    Aug 2009
    Location
    Central NC
    Posts
    1,466
    Quote Originally Posted by stevenje View Post
    The first fiber optic job I worked on was a project for IBM back in the 90's. We ran 1-1/2" EMT, no bends larger than 22 1/2º and 24" x 24" x 6" pull boxes where ever you had to turn 90º. Along with many other restrictions, it was a challenging job finding a path above the existing drop ceilings.
    IBM was where I did this project too, in Research Triangle Park, NC. IBM was always a challenge. Along with the normal challenges of the jobs, they usually had their own criteria as well. If you could satisfy IBM, you could satisfy anyone. I think we ran 3/4 and 1 inch EMT for those cables. Seems the cables were to be pulled by someone else. I wasn't full time on that job, went there nights & Saturdays, so I don't remember as many details.

    The good thing about IBM was that we sometimes saw products for the first or only time. They used a lot of high end, high dollar lights, etc. Had a dimmer panel I never saw anywhere else. Some chance to learn out of the way products.

    Bad thing was dealing with their odd ways. We had hallways we couldn't enter at certain times of day, regardless of traffic volume. Project managers would pick someone over smallest details and demand things impossible to accomplish. We did a briefing center where 1 of our crews had to use shallow boxes over a counter against a concrete wall. 2-3 layers of drywall. Devices barely fit boxes. Standard plates barely fit right over them. Then some IBM hot shot didn't like the plates & ordered some special metal plates with grainy finish, etc. PLATE HAD A FLAT BACK, NO HOLLOW OR "SHELL" AT ALL. Plates did not fit. 1 of their guys demanded I fix it when I was there on another job. I took a look & told him to call my boss, that I could not help him. "But I want it fixed right now". I said "you can't have it right now. You outsmarted yourself with these plates you should have known would not fit. I am here to work on lights. Call my boss & complain to him about plates. I can't help you." He complained that I was rude to him. The boss backed me up & said he'd tried to tell him same thing before he ordered the plates. Some people are very intelligent but not very smart.
    Yes, I'll be happy to do a first class job for less than anyone else and take a dollar a week for 10 years.

  9. #39
    Join Date
    Aug 2007
    Posts
    457
    Quote Originally Posted by jmellc View Post
    IBM was where I did this project too, in Research Triangle Park, NC. IBM was always a challenge. Along with the normal challenges of the jobs, they usually had their own criteria as well. If you could satisfy IBM, you could satisfy anyone.
    I worked at the IBM facility outside of Boulder, CO. The company that I started out in this trade with (early 70's) had a full time crew at IBM. One of my jobs as the new "shop boy", was to spray paint ivory steel Stemco cover plates with "IBM Blue" paint. I wish I had a nickle for everyone of those I painted. I'd be a rich man. I smile when I think of those days gone by. Great jobs, great people and good money.

  10. #40
    Join Date
    Aug 2009
    Location
    Central NC
    Posts
    1,466
    Quote Originally Posted by stevenje View Post
    I worked at the IBM facility outside of Boulder, CO. The company that I started out in this trade with (early 70's) had a full time crew at IBM. One of my jobs as the new "shop boy", was to spray paint ivory steel Stemco cover plates with "IBM Blue" paint. I wish I had a nickle for everyone of those I painted. I'd be a rich man. I smile when I think of those days gone by. Great jobs, great people and good money.
    Yes, I can imagine IBM wanting the covers painted like that. I started in 1976. Did electrical for 2 years, went to school, did electrical, tried other things a few years. Went back to electrical in 1995. If I were doing it over again, I'd have stayed with it 1st time. $ was not that good where I worked then (eastern NC), but the co. I worked for got all kinds of work, from lights in the outhouse to industrial plants. A good place to learn. I could have started my own thing in the early 80's & made pretty good. I worked with some good people I'd like to connect with again. I was young & foolish then, older & less foolish today. Today's market is intense like never before, as I see it.
    Yes, I'll be happy to do a first class job for less than anyone else and take a dollar a week for 10 years.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •