NCCER Elc L1/M7 MIX

By Jeff Scully

Created 3 years ago

Duration 0:00:00

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Slide Content

Tags: NCCER Electrical

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
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
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.
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.
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.
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.
Slide 8 - 1.0.0 – 2.0.0
- Hand Bending 26107-14
- What’s wrong with this picture?
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.
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.
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).
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.
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.
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.
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
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.
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.
Slide 18 - 2.5.0
- Hand Bending 26107-14
- Common Offset Factors
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.
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.
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.
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.
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.
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.
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.
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.
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.
Slide 28 - 2.8.0
- Hand Bending 26107-14
- Four-Bend Saddle
- A four-bend saddle is created using two offset bends.
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.
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
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.
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.
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.
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.
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.
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
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

NCCER Elc L1/M7 MIX

NCCER Elc L1/M7 MIX

Slide 2 - Objectives

Slide 3 - Performance Tasks

Slide 4 - 1.0.0 – 2.0.0

Slide 5 - 1.0.0 – 2.0.0

Slide 6 - 1.0.0 – 2.0.0

Slide 7 - 1.0.0 – 2.0.0

Slide 8 - 1.0.0 – 2.0.0

Slide 9 - 1.0.0 – 2.0.0

Slide 10 - 2.1.0

Slide 11 - 2.1.0

Slide 12 - 2.2.0

Slide 13 - 2.2.0

Slide 14 - 2.3.0

Slide 15 - 2.4.0

Slide 16 - 2.5.0

Slide 17 - 2.5.0

Slide 18 - 2.5.0

Slide 19 - 2.6.0

Slide 20 - 2.6.0

Slide 21 - 2.6.0

Slide 22 - 2.6.0

Slide 23 - 2.7.0

Slide 24 - 2.7.0

Slide 25 - 2.7.0

Slide 26 - 2.7.0

Slide 27 - 2.8.0

Slide 28 - 2.8.0

Slide 29 - 2.8.0

Slide 30 - 2.8.0

Slide 31 - 3.0.0 – 3.1.0

Slide 32 - 3.2.0

Slide 33 - 3.3.0

Slide 34 - 3.3.0

Slide 35 - 3.4.0 – 3.5.0

Slide 36 - Wrap Up

Slide 37 - Next Session…