NCCER Elc L1/M7 MIX

NCCERElectrical
1.0x

NCCER Elc L1/M7 MIX

Created 3 years ago

Duration 0:00:00
lesson view count 1069
Select the file type you wish to download
Slide Content
  1. Objectives

    Slide 2 - Objectives

    • When trainees have completed this session, they should be able to do the following:
    • 1. Identify the methods for hand bending and installing conduit.
    • 2. Determine conduit bends.
    • 3. Make 90° bends, back-to-back bends, offsets, kicks, and saddle bends using a hand bender.
    • 4. Cut, ream, and thread conduit.
    • Hand Bending 26107-14
  2. Performance Tasks

    Slide 3 - Performance Tasks

    • 1. Make 90° bends, back-to-back bends, offsets, kicks, and saddle bends using a hand bender.
    • 2. Cut, ream, and thread conduit.
    • Hand Bending 26107-14
  3. 1.0.0 – 2.0.0

    Slide 4 - 1.0.0 – 2.0.0

    • Hand Bending 26107-14
    • Introduction; Hand Bending Equipment
    • • Hand benders are available in various sizes and used to bend rigid conduit and electrical metallic tubing (EMT) up to 1¼" in diameter.
    • • The same bender can be used on different sizes of EMT and rigid because while their inside diameters vary, the outside diameters are roughly equal.
  4. 1.0.0 – 2.0.0

    Slide 5 - 1.0.0 – 2.0.0

    • Hand Bending 26107-14
    • Pushing Down on the Bender to Complete the Bend
    • • To use a hand bender, place it on a flat, firm surface and bend down.
    • • Use both hand and foot pressure to ensure a good bend.
  5. 1.0.0 – 2.0.0

    Slide 6 - 1.0.0 – 2.0.0

    • Hand Bending 26107-14
    • Hickeys
    • • Hickeys are used for rigid metal conduit (RMC) and intermediate metal conduit (IMC) only.
    • • Hickeys make segment bends in small increments.
  6. 1.0.0 – 2.0.0

    Slide 7 - 1.0.0 – 2.0.0

    • Hand Bending 26107-14
    • Typical PVC Heating Units
    • • Polyvinyl chloride (PVC) conduit is bent using a special heating unit.
    • • After the PVC is heated, it is removed from the unit and the bending performed by hand.
  7. 1.0.0 – 2.0.0

    Slide 8 - 1.0.0 – 2.0.0

    • Hand Bending 26107-14
    • What’s wrong with this picture?
  8. 1.0.0 – 2.0.0

    Slide 9 - 1.0.0 – 2.0.0

    • Hand Bending 26107-14
    • Typical Plug Set
    • • Plug sets are used for PVC that is 2" in diameter or larger.
    • • The plugs help prevent the PVC from flattening during a bend and are removed when the PVC has cooled. A damp sponge or cloth can be used to set the PVC faster.
  9. 2.1.0

    Slide 10 - 2.1.0

    • Hand Bending 26107-14
    • Geometry Required to Make a Bend
    • • The mathematics of right triangles can be applied to bends to find unknown values.
    • • In a bend, the offset forms the hypotenuse of the right triangle.
  10. 2.1.0

    Slide 11 - 2.1.0

    • Hand Bending 26107-14
    • Circles and 90° Bends
    • • A 90° bend is ¼ of a circle.
    • • Concentric bends are made to 90° but each has a different radius so that they fit within one another.
    • • To calculate the circumference of a circle, multiply pi times the diameter (πD), or multiply two times pi times the radius (2πR).
  11. 2.2.0

    Slide 12 - 2.2.0

    • Hand Bending 26107-14
    • Making a 90° Bend
    • • To make a bend, you must know the stub-up length and the take-up distance of the bender.
    • • The take-up is the amount of conduit that will be used to form the bend and is listed in the manufacturer’s instructions for the bender.
    • Performance Task
    • Make a 90° Bend
    • Have the trainees demonstrate how to make a 90° bend.
  12. 2.2.0

    Slide 13 - 2.2.0

    • Hand Bending 26107-14
    • Bending an 18-inch Stub-Up
    • • To make a 90° stub-up, subtract the bender take-up from the stub-up height. Mark that distance on the conduit and line it up with the starting point on the bender.
    • • Hold the conduit with one foot and press the foot pedal with the other. Keep the bender perpendicular and bend in a single smooth motion.
    • • After making a bend, check it for accuracy using a level or square.
  13. 2.3.0

    Slide 14 - 2.3.0

    • Hand Bending 26107-14
    • Gain
    • • Gain is the distance saved by the arc of a 90° bend. It is important to know the gain before cutting and threading conduit.
    • • The developed length of 90° bend can be found by adding the lengths of both sides and subtracting the gain.
  14. 2.4.0

    Slide 15 - 2.4.0

    • Hand Bending 26107-14
    • Back-to-Back 90° Bends
    • • To make a back-to-back bend, make the first bend as usual, then measure the required distance between bends from the back of the first bend. Mark it on the conduit.
    • • Place the bender’s back-to-back indicator mark at this point and bend up.
    • Performance Task
    • Make Back-to-Back Bends
    • This session will conclude with trainees making back-to-back bends.
    • Next Session…
    • Making an Offset
  15. 2.5.0

    Slide 16 - 2.5.0

    • Hand Bending 26107-14
    • Making an Offset
    • • An offset consists of two equal bends of less than 90° each and is used to route conduit over other objects.
    • • To avoid a difficult wire pull, use a shallow offset angle whenever possible.
    • • The distance between bends is equal to the depth of the offset times a multiplier.
  16. 2.5.0

    Slide 17 - 2.5.0

    • Hand Bending 26107-14
    • Shrinkage Calculation
    • • Offset angle multipliers represent the cosecant of the related offset angle (rounded).
    • • The shrinkage must be multiplied by the height of the rise and subtracted from the developed length.
  17. 2.5.0

    Slide 18 - 2.5.0

    • Hand Bending 26107-14
    • Common Offset Factors
  18. 2.6.0

    Slide 19 - 2.6.0

    • Hand Bending 26107-14
    • Parallel Offsets
    • • The conduit length must be adjusted when making parallel offsets.
    • • The amount to be added is equal to the center-to-center spacing times the tangent of one-half the offset angle. Tangent values can be found in Appendix A.
  19. 2.6.0

    Slide 20 - 2.6.0

    • Hand Bending 26107-14
    • Center of First Bend
    • To create a parallel offset, first find the center of the first bend of the innermost conduit.
  20. 2.6.0

    Slide 21 - 2.6.0

    • Hand Bending 26107-14
    • Successive Center Lines
    • • The starting point of the second conduit is found using the offset formula [12" + center-to-center spacing x TAN (½ offset angle)] and then added to the starting point measurement of the first pipe.
    • • This value is added again to find the starting point of the outermost pipe.
  21. 2.6.0

    Slide 22 - 2.6.0

    • Hand Bending 26107-14
    • Parallel Offset Pipes
    • Performance Task
    • Make Offset Bends
    • Have the trainees demonstrate how to make offset bends.
  22. 2.7.0

    Slide 23 - 2.7.0

    • Hand Bending 26107-14
    • Saddle Bends
    • • Saddle bends are used to route conduit around obstructions.
    • • Making a saddle bend will cause the conduit to shorten by a specified amount for every inch of saddle depth, depending on the size of the conduit.
  23. 2.7.0

    Slide 24 - 2.7.0

    • Hand Bending 26107-14
    • Shrinkage Chart for Saddle Bends
    • • The value from a shrinkage chart is added to the measurement from the end of the conduit to the centerline.
    • • This ensures that the bend will be centered over the obstruction.
  24. 2.7.0

    Slide 25 - 2.7.0

    • Hand Bending 26107-14
    • Measurement Locations
    • Using the value for a two-inch obstruction found in the shrinkage chart, each bend is located 5" from the centerline.
  25. 2.7.0

    Slide 26 - 2.7.0

    • Hand Bending 26107-14
    • Location of Bends
    • This saddle contains one 45° and two 22½° bends. Note that the center mark is placed ahead to account for shrinkage.
  26. 2.8.0

    Slide 27 - 2.8.0

    • Hand Bending 26107-14
    • Four-Bend Saddles
    • A four-bend saddle must be laid out carefully in order to avoid wasting conduit.
  27. 2.8.0

    Slide 28 - 2.8.0

    • Hand Bending 26107-14
    • Four-Bend Saddle
    • A four-bend saddle is created using two offset bends.
  28. 2.8.0

    Slide 29 - 2.8.0

    • Hand Bending 26107-14
    • Four-Bend Saddle Measurements
    • • To lay out a four-bend saddle, determine the height of the offset and the correct spacing, then bend the first offset.
    • • Mark the starting point for the second offset and bend the offset. Remember to use the multiplier for the offset angle and account for shrinkage.
  29. 2.8.0

    Slide 30 - 2.8.0

    • Hand Bending 26107-14
    • Bend and Offset Measurements
    • Performance Task
    • Make Saddle Bends
    • Have the trainees demonstrate how to make saddle bends.
    • Next Session…
    • Cutting, Reaming, and Threading Conduit
  30. 3.0.0 – 3.1.0

    Slide 31 - 3.0.0 – 3.1.0

    • Hand Bending 26107-14
    • Cutting, Reaming, and Threading Conduit
    • • RMC, IMC, and EMT are sold in 10' sections and normally cut to length using a hacksaw.
    • • Select the correct blade for the material being cut and make sure the cut is straight and smooth.
  31. 3.2.0

    Slide 32 - 3.2.0

    • Hand Bending 26107-14
    • Pipe Cutter Method
    • • Pipe cutters can be used on RMC and IMC.
    • • Turn the handle ¼ turn for each full turn around the conduit. Avoid overtightening.
  32. 3.3.0

    Slide 33 - 3.3.0

    • Hand Bending 26107-14
    • Reaming Conduit
    • • After cutting, conduit must be reamed to remove any burrs or sharp edges.
    • • A file can be used when a reamer is not available.
  33. 3.3.0

    Slide 34 - 3.3.0

    • Hand Bending 26107-14
    • Reamer Rotation
    • • Rotate a reamer in a downward motion.
    • • Remove the reamer by pulling back while continuing to rotate it.
  34. 3.4.0 – 3.5.0

    Slide 35 - 3.4.0 – 3.5.0

    • Hand Bending 26107-14
    • Threading Conduit; Cutting and Joining PVC Conduit
    • • RMC and IMC can be threaded to accept threaded fittings.
    • • Ratchet threaders are available that produce from 8 to 18 threads per inch.
    • • PVC can be cut with a hacksaw and deburred with a pocket knife before joining with PVC cement.
    • Performance Task
    • Cut, Ream, and Thread Conduit
    • This session will conclude with trainees cutting, reaming, and threading conduit.
  35. Wrap Up

    Slide 36 - Wrap Up

    • 3-2-1
    • 3 – Write 3 important things learned during class
    • 2 – Write 2 questions you have about the material
    • 1 – Write 1 thought you had about the material
    • Hand Bending 26107-14
  36. Next Session…

    Slide 37 - Next Session…

    • MODULE EXAM
    • Review the complete module to prepare for the module exam. Complete the Module Review as a study aid.
    • Hand Bending 26107-14