NCCER Electrical L2/M2

1.0x

NCCER Electrical L2/M2

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Slide Content
  1. Objectives

    Slide 2 - Objectives

    • When trainees have completed this lesson, they should be able to do the following:
    • 1. Describe the different types of nonmetallic and metallic pull and junction boxes.
    • 2. Properly select, install, and support pull and junction boxes and their associated fittings.
    • 3. Describe the National Electrical Code® (NEC®) regulations governing pull and junction boxes.
    • 4. Size pull and junction boxes for various applications.
    • 5. Understand the NEMA and IP classifications for pull and junction boxes.
    • 6. Describe the purpose of conduit bodies and Type FS boxes.
    • Pull and Junction Boxes 26205-14
  2. Performance Tasks

    Slide 3 - Performance Tasks

    • 1. Identify various NEMA boxes.
    • 2. Properly select, install, and support pull and junction boxes over 100 cubic inches in size.
    • 3. Identify various conduit bodies and fittings.
    • Pull and Junction Boxes 26205-14
  3. 1.0.0 – 1.2.0

    Slide 4 - 1.0.0 – 1.2.0

    • Pull and Junction Boxes 26205-14
    • Introduction
    • • Pull and junction boxes can be used to provide pull points or to make conductor connections.
    • • NEC Article 314 covers pull and junction box requirements.
    • • Boxes for damp and wet locations must be nonconductive and protected against the entry of moisture.
  4. 1.0.0 – 1.2.0

    Slide 5 - 1.0.0 – 1.2.0

    • Pull and Junction Boxes 26205-14
    • IP Classification System
    • The ingress protection (IP) classification system uses a two-digit number to represent the enclosure’s degree of protection against solid objects and water.
  5. 1.0.0 – 1.2.0

    Slide 6 - 1.0.0 – 1.2.0

    • Pull and Junction Boxes 26205-14
    • NEMA and IP Enclosures
    • • A cross-reference between NEMA and IP enclosure classifications is shown here.
    • • Common NEMA Types include Type 1, for general-purpose indoor applications, and Type 3, which is commonly used in outdoor applications such as construction work.
    • Performance Task
    • This session will conclude with trainees identifying various NEMA boxes.
  6. 2.0.0 – 2.2.0

    Slide 7 - 2.0.0 – 2.2.0

    • Pull and Junction Boxes 26205-14
    • Sizing Pull and Junction Boxes
    • • Pull and junction boxes eliminate bends and provide strain relief during longer pulls.
    • • Pull and junction boxes must provide sufficient free space for the conductors. For straight pulls, the minimum length of the box is eight times the trade size of the largest conduit.
  7. 2.0.0 – 2.2.0

    Slide 8 - 2.0.0 – 2.2.0

    • Pull and Junction Boxes 26205-14
    • Pull Box With Conduit Runs Entering at Right Angles
    • • For pull and junction boxes in which the conductors are pulled at an angle, the minimum length of the box is six times the trade size of the largest conduit, plus the sum of all other conduit diameters entering the box.
    • • The installation of boxes in systems over 1,000V must meet the requirements of NEC Article 314, Part IV.
    • Next Session…
    • Conduit Bodies
  8. 3.0.0 – 3.8.0

    Slide 9 - 3.0.0 – 3.8.0

    • Pull and Junction Boxes 26205-14
    • Conduit Bodies
    • • Conduit bodies provide access to the system through a removable cover and are typically used with rigid or intermediate metal conduit.
    • • Conduit bodies can be identified by holding the body like a pistol and observing where the opening is.
  9. 3.0.0 – 3.8.0

    Slide 10 - 3.0.0 – 3.8.0

    • Pull and Junction Boxes 26205-14
    • Type C Conduit Body
    • • A Type C conduit body has a straight body with a cover.
    • • Type C conduit bodies can be used to provide a pull point in a long run or a run with bends totaling more than 360 degrees.
  10. 3.0.0 – 3.8.0

    Slide 11 - 3.0.0 – 3.8.0

    • Pull and Junction Boxes 26205-14
    • Type L Conduit Bodies
    • • Type L conduit bodies are used to provide a 90-degree change in direction.
    • • Type L conduit bodies are available with the cover on the back (LB) and either or both sides (LL, LR, or LRL).
  11. 3.0.0 – 3.8.0

    Slide 12 - 3.0.0 – 3.8.0

    • Pull and Junction Boxes 26205-14
    • Type T Conduit Body
    • • Type T conduit bodies are used to provide a junction point for three intersecting conduits and low point drains.
    • • When installing electrical metallic tubing (EMT), it is more cost effective to use a square box rather than than a Type T conduit body.
  12. 3.0.0 – 3.8.0

    Slide 13 - 3.0.0 – 3.8.0

    • Pull and Junction Boxes 26205-14
    • Type X Conduit Body
    • • Type X conduit bodies provide a junction point for four intersecting conduits.
    • • Type FS and FD boxes are precision molded, gasketed fittings used in industrial environments.
  13. 3.0.0 – 3.8.0

    Slide 14 - 3.0.0 – 3.8.0

    • Pull and Junction Boxes 26205-14
    • Elbows
    • • Pulling elbows are used to facilitate cable installation. They do not provide sufficient space for wiring connections.
    • • An entrance ell (SLB) contains an offset that attaches to the support surface.
  14. 3.0.0 – 3.8.0

    Slide 15 - 3.0.0 – 3.8.0

    • Pull and Junction Boxes 26205-14
    • Mogul
    • • Moguls have a raised access cover to provide better access for installation and maintenance.
    • • Larger moguls may contain built-in rollers to facilitate cable installation.
  15. 4.0.0 – 4.2.0

    Slide 16 - 4.0.0 – 4.2.0

    • Pull and Junction Boxes 26205-14
    • Handholes
    • • Handholes are larger boxes used to provide access for conductor installation, operation, and maintenance.
    • • Handholes are often installed with underground conduit used for traffic lights, streetlights, and landscaping lights. They must be installed and constructed to protect against environmental damage and traffic or other loads.
  16. 4.0.0 – 4.2.0

    Slide 17 - 4.0.0 – 4.2.0

    • Pull and Junction Boxes 26205-14
    • Handhole Containing Traffic Signal Wiring
    • • Handholes must be effectively bonded and constructed to ensure that they remain safe and reliable for the lifetime of the intended application.
    • • A solid footing is essential to prevent structural failure.
  17. 5.0.0 – 5.3.0

    Slide 18 - 5.0.0 – 5.3.0

    • Pull and Junction Boxes 26205-14
    • Fittings
    • • EMT is too thin for threading and uses either setscrew or compression fittings.
    • • Compression fittings listed as raintight can be used outdoors or in wet locations.
  18. 5.0.0 – 5.3.0

    Slide 19 - 5.0.0 – 5.3.0

    • Pull and Junction Boxes 26205-14
    • Setscrew Fittings
    • • EMT setscrew fittings can only be used in dry locations.
    • • EMT requires connectors at each termination point. They can be of the setscrew or compression type, and include a locknut and bushing to protect the conductors at the connection point.
  19. 5.0.0 – 5.3.0

    Slide 20 - 5.0.0 – 5.3.0

    • Pull and Junction Boxes 26205-14
    • Think About It:Setscrew and Compression Fittings
    • This picture shows both setscrew and compression fittings. Which type provides a better connection? Why?
  20. 5.0.0 – 5.3.0

    Slide 21 - 5.0.0 – 5.3.0

    • Pull and Junction Boxes 26205-14
    • Rigid Metal Conduit with Coupling
    • • RMC, IMC, and aluminum all have sufficient wall thickness to permit threading and use various types of threaded connectors.
    • • Double locknuts are used at conduit-to-box connections.
  21. 5.0.0 – 5.3.0

    Slide 22 - 5.0.0 – 5.3.0

    • Pull and Junction Boxes 26205-14
    • Combination Couplings
    • Combination couplings are used to transition between rigid and flexible conduit such as at motors.
  22. 5.0.0 – 5.3.0

    Slide 23 - 5.0.0 – 5.3.0

    • Pull and Junction Boxes 26205-14
    • Metal Conduit Couplings
    • • A variety of couplings are available for different applications.
    • • Threadless (setscrew) couplings are not permitted in most hazardous locations, but can be used outdoors or in concrete if listed for the application.
  23. 5.0.0 – 5.3.0

    Slide 24 - 5.0.0 – 5.3.0

    • Pull and Junction Boxes 26205-14
    • Common Types of Locknuts
    • • Locknuts are typically installed on both the inside and outside walls of an enclosure connection.
    • • A grounding locknut may be required if bonding jumpers are used in the enclosure.
    • • Sealing locknuts are available to make watertight connections where required.
  24. 5.0.0 – 5.3.0

    Slide 25 - 5.0.0 – 5.3.0

    • Pull and Junction Boxes 26205-14
    • Typical Bushings Used at Termination Points
    • • Bushings can be made of metal, plastic, or fiber.
    • • Bushings protect conductors from the sharp edges of conduit and enclosures.
  25. 5.0.0 – 5.3.0

    Slide 26 - 5.0.0 – 5.3.0

    • Pull and Junction Boxes 26205-14
    • Regular Insulating Bushings and Grounding Insulating Bushings
    • • Plastic insulating bushings are often color coded by conduit size.
    • • Grounding bushings are available to permit the installation of a ground wire.
  26. 5.0.0 – 5.3.0

    Slide 27 - 5.0.0 – 5.3.0

    • Pull and Junction Boxes 26205-14
    • Myers-Type (Gasketed) Hub
    • • Myers hubs are gasketed fittings with an integral O-ring used to provide a watertight seal in wet locations. They are typically found on the top of enclosures where water tends to accumulate.
    • • Listed watertight enclosures may require the use of Myers hubs at all entry points.
  27. 5.0.0 – 5.3.0

    Slide 28 - 5.0.0 – 5.3.0

    • Pull and Junction Boxes 26205-14
    • Knockout Punch Kit
    • • Some enclosures include precut knockouts while others require the use of a knockout punch.
    • • A manual knockout punch uses a predrilled pilot hole and a die/drive nut to cut a hole in the enclosure.
  28. 5.0.0 – 5.3.0

    Slide 29 - 5.0.0 – 5.3.0

    • Pull and Junction Boxes 26205-14
    • Battery-Powered Knockout Kit
    • When numerous knockouts are required, battery-powered and hydraulic knockout kits can be used.
  29. 5.0.0 – 5.3.0

    Slide 30 - 5.0.0 – 5.3.0

    • Pull and Junction Boxes 26205-14
    • Hydraulic Knockout Kit
    • Next Session…
    • Performance Tasks
  30. Performance Tasks

    Slide 31 - Performance Tasks

    • Pull and Junction Boxes 26205-14
    • During this session, trainees practice properly selecting, installing, and supporting pull and junction boxes over 100 cubic inches in size and identifying various conduit bodies and fittings.
    • Next Session…
    • Wrap Up
  31. Wrap Up

    Slide 32 - 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
    • Pull and Junction Boxes 26205-14
  32. Next Session…

    Slide 33 - Next Session…

    • MODULE EXAM
    • Review the complete module to prepare for the module exam. Complete the Module Review as a study aid.
    • Pull and Junction Boxes 26205-14