electrical conduit radius formulas offset You may or may not need to know how to bend conduit, depending on your choice of fields. This app works great and is very accurate. The calculator shows that the sine of a 2-degree angle is .0349. I previously tried your multiplier of 6, and was unsuccessful, today I tried 5.75 with a spacing of 28.75. Somehow I missed this comment but you filled in nicely. Answer: There is no real formula, but it can be calculated with a fair degree of precision. I'm grateful to you and your work, from here in Canada. As an exercise, consider an offset of 12" using two 22 bends.

Dan Harmon (author) from Boise, Idaho on October 14, 2010: You are more than welcome. What are B and C? Easily select between different types of benders and choose the size of the shoe and conduit type that you're using. Shrinkage can be calculated as C - B, with B = cosine d * C. But that is all figured with the 90 already bent. multiplier conduit My green helper can now bend pipe better then the old timers and I love it! Again, C = A / sine(22). I'm curious as to why you would add 1.25" to determine the minimum radius of a 2" conduit (as used in ugly's multi-shot:90 degree bending example. Then mark line "C" using same measurement as line "B" above but mark on opposite side of center Line "A". I applied this to bending rigid ocal, and it got me pretty darn close. The length of side B is the length of side A divided by the tangent of angle (d). Good simple calculations. for a memory aid: Chief Sohcahtoa S= O/H C=A/H T=O/A, probably works for me since I'm Cherokee ;-). It's always nice to hear that my writing has been of value. Shoot us an email and we will get right back to you! I guess my almost perfect pipe will be getting outfitted with a nice new coupling lol :) at least it wasn't too small.. Great info going to tell lots of apprentices to do it get on your site tough teaching the young guys. Answer: Assuming your brand of bender uses the minimum radius of bends (most do) the NEC indicates that that figure is 4.5" for 3/4 pipe. Is there anything else I should learn and which is the toughest thing to learn. I want to study more so as to know more. I enjoyed your article, particularly the comments. The angle "d" is the angle at which the conduit is bent. offset rolling bend Dan Harmon (author) from Boise, Idaho on October 03, 2011: I'm sorry, I'm not familiar with that term - it isn't used in my area. Referring to the diagrams in the article, the length of C will be the length of A divided by the sine of angle D. Measurements will be taken from the back of the 90. Thanks again.

Have been using it for almost 2 years now. ), marks a little off (although 10" off would be horrible!

ABANG RAYMOND OJONG on November 03, 2010: thanks for sharing knowledge and teaching others. Each set of formulassine, cosine, and tangentare just the same formula expressed three different ways. What is the conduit shrinkagethat is, the amount by which the center of the bend will be closer to the end of the conduit than the measured length of pipe? As an electrician myself, I have often found myself attempting to bend large conduit into odd angles and dimensions to match the demands of a building or get the appearance people want. 1/8=.125, 2/8 (or 1/4)=.25, 3/8=.375 and so on. I didn't space my bends at 37 like i said they were 28.75. This is all assuming that the pipe is a pencil line, not a 3-dimensional object, which we know is not true. And yes, math and its associated items (reading a tape measure perhaps) is very important and for someone that has no training in math at all even simple addition or subtraction of fractional figures can be difficult. ), an inaccurate or poorly placed protractor, etc. But i still find myself coming back. Are you referring to an example in Ugly's? Terms of Use Most conduit bends, in addition to a simple 90-degree bend, can be understood and calculated using the geometry of a right triangle. I found your explanations of the calculations easy to follow and I have sent links to your articles to all of my employees. I'll recommend this to any electrician on site who is seeking to either learn, or just improving on their skill and efficiency. Even if you only bend conduit a couple times a year for work or home, this app is a MUST. Your calculator will give you the sine, cosine, and tangent of any angle. For example, if you had from left to right, 1/2" pipe and a 3/4" pipe, the offset on your 1/2" starting at 24" and you were bending 30 degree bends for a 6" offset, and you wanted 1" between your pipes, you'd make the following marks, measuring from bottom up. You guys hit a home run with this app! I am certain they will find them helpful. You can find these on a calculator by dividing 1 by 8 for instance, which is 1/8 or .125. And now that we have smartphones, the calculator isn't just cheap; it's free. Julie Burke from Alaska on October 04, 2010: I didn't even realize that trig would be pertinent to bending conduit! You can even measure the bends with a protractor. Thanks a lot for the speedy response and lengthy information! Dan Harmon (author) from Boise, Idaho on September 15, 2014: That depends on what you are doing. That would be dependent on the bender used. What is the length loss of a 90 bend? In real life, of course, conduit is not a one-dimensional line, but rather a three-dimensional object with curved, not sharp, corners.

The problem is that the radius of the bend varies with the size of pipe so instead of using the bender to determine the radius it must be matched to that of the largest conduit. Stuff. Ive been able to move away from doing lazy easy bends and have greatly decreased the number of j boxes and pull points I need to install. While this is not usually important in smaller conduit, it most definitely comes into play in the bigger stuff. Learning to read blueprints and sometimes schematics will be important. Keep in mind that those are INTERIOR angles.

(not to be confused the shrinkage you get with offsets) it's useful to know if you want to cut and thread your pipe before bending it. Question: how do i figure out the development for a 15 degree saddle bend if the center line radius is 25"? Multiply the radius of the bend you want to make by 6.28, then by degrees, bend and divide by 360. He finally decided to weather the awful process of my 'math' usage, and sunnuva'gun if he didn't ask me later if I would go over some of the fine points with him , etc. Question: I have a 10' piece of 3/4" aluminum electrical conduit. From my understanding I'm going to learn about electrician tools, wiring, how to wire up motors, PLC n controls, power distribution, electric codes, blueprints schematics, electronic component circuits, a little construction, and how to bend conduit.

The "length" of the bend is then 4.5", but the length of pipe used to make that bend is 3.14*4.5/2, or 7". Most of the time the math is built into the tools we use, but as I'm sure you realize, math is behind many things we take for granted. That is, the sine of angle d is the length of side A divided by the length of side C. The length of side A is sine (d) times the length of side C. The length of side C is the length of side A divided by sine (d). That's always good to hear. Quickly calculate conduit bends for a variety of angles and depths. Finally, it is very easy to over or under bend pipe at ten degrees. Many protractors are very difficult to read exactly what you want, and 1 or 2 degrees off is very common. JD Curtin from Brighton, Colorado on December 02, 2015: Wow this is great! The "B" bend is not at the same point on the bender, but at the center of the chosen degree for the center bend. This isn't hard to do with large benders. I tried 22 degrees as close together as possible, it was over 9 inches. And thanks for the compliment; if you're happy with the hub it must be of some use to you. I once made a 180-degree bend that was nearly 100 yards across. There will be some "shrinkage", which can be found by the math formula of Shrink=4.25-4.25*cos(22) = .31" in your case. I'm sure the problem is in the bending process - the wrong angle (are you using the bender on it's side and measuring with the rod that comes out to indicate bend? Dan has been a licensed journey-level electrician for 17 years. The difference between B and C is our shrinkage; the center of our three-point saddle will move just under 1". In particular, you will have to know how to get inverse functions on your calculator; these functions convert a sine, cosine, or tangent figure into an angle, into the degrees of bend you need. 160 (they also reference the wrong page which brings you to hand signals, ha,ha). A history buff might use it, though - thanks for the tip. The sine of 5 degrees is .087, and 2 / .087 = 22.98, or about 23". Wiring homes, for instances have little to no conduit bending. Even more experienced journey-level electricians seldom have any idea of the wide range of possibilities available. The math and formulas that make up a simple conduit-bending guide are actually quite simple and easily learned. I've never found it necessary to measure closer than 1/8" in the field so it works fine there. Hahahahah. Measure the conduit and make the same bends. The "hook" that the pipe fits through sometimes doesn't want to come all the way back to the shoe, the bottom shoe may not be fully back, etc. going to school for conduit bending with union and learning about shrink and gain. Answer: Not in the sense of the formulas given here. Divide once more by two, measure from the center of the pipe that far then set that mark at the front edge of the bending shoe. Asher Socrates from Los Angeles, CA on February 21, 2016: This is a very detailed and superb write up! Have you picked up an error elsewhere in the article that I missed when proofreading? Only a few numbers and math operations need to be memorized to make offsets, saddles and 90 degree bends. I use the bender standing upright it has the stand and the little plate thing it slides along as its being bent. I understand that in class that might not be close enough, and you could go the extra distance and memorize each 1/16" as well, but it won't usually match exactly, either. Some thoughts here: I always use the bender upright, which requires someone to hold it from falling over. Amazing. Two examples of angle finders from Amazon are shown below. I've heard ppl say that AC theory n conduit bending are a bitch. Dan Harmon (author) from Boise, Idaho on December 14, 2013: Not bad, although a few of additions need to be made. Thank you :o). Brought back memories from trig. Dan Harmon (author) from Boise, Idaho on September 23, 2013: Knowing electric codes is huge. Again, it will not be exact, but might be close enough for practical application in the field. There is no deduct except when doing 90 degrees on a hand bender. I always start with the basic bends first. See and edit your bender's information (Center-line Radius, Deduct, Gain, Setback, Travel, and Radius Adjustment) within the 'Bender Specs' section. Now we multiply this 2.125" by the tangent of half the offset angle, which happens to be 30 degrees, so half will be 15 degrees. Very intense information. You're on the right track here, and your math is correct - you even caught that the multiplier for 10 degrees is not 6, but actually 5.75 (6 is just a usable figure that is easy to work with).

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