NEMA VE-2 2018 Watermarked 2022-01-19 PDF

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Normas para la instalación de bandejas porta cables y accesorios...

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NEMA Standards Publication VE 2-2018 Cable Tray Installation Guidelines

Endorsed by Cable Tray Institute www.cabletrays.com Published by: National Electrical Manufacturers Association 1300 North 17th Street, Suite 900 Rosslyn, Virginia 22209 www.nema.org © 2020 National Electrical Manufacturers Association. All rights, including translation into other languages, reserved under the Universal Copyright Convention, the Berne Convention for the Protection of Literary and Artistic Works, and the International and Pan American copyright conventions.

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NEMA VE 2-2018 Page i

CONTENTS FOREWORD ............................................................................................................................................... vii SECTION 1 SCOPE ...................................................................................................................................... 1 1.1 Scope ......................................................................................................................................... 1 1.2 General ...................................................................................................................................... 1 1.3 Definitions, Abbreviations, and Acronyms ................................................................................. 1 1.4 References ................................................................................................................................ 3 1.4.1 Contacts......................................................................................................................... 4 1.5 Receiving and Unloading........................................................................................................... 4 SECTION 2 STORAGE ................................................................................................................................ 6 SECTION 3 INSTALLATION ........................................................................................................................ 7 3.1 Cable Tray Installation Locations .............................................................................................. 7 3.2 Common Tools for Installation ................................................................................................... 7 3.3 Support Installation .................................................................................................................... 7 3.3.1 Trapeze Type ................................................................................................................ 8 3.3.2 Hanger Rod Clamp ...................................................................................................... 10 3.3.3 Center Hung Support................................................................................................... 11 3.3.4 Single Channel Cable Tray Hanger ............................................................................. 12 3.3.5 Double Channel Cable Tray Hanger ........................................................................... 12 3.3.6 Single-Rail Cable Tray Hangers .................................................................................. 12 3.3.7 Wall and Cantilever Brackets ...................................................................................... 13 3.3.8 Floor and Roof Installations ......................................................................................... 14 3.3.9 Vertical Installations ..................................................................................................... 15 3.3.10 Transverse Installations ............................................................................................. 16 3.4 Straight Section Installation ..................................................................................................... 17 3.4.1 Straight Section Position ............................................................................................. 17 3.4.2 Expansion Splice Plates .............................................................................................. 18 3.4.3 Vertical Adjustable Splice Plates ................................................................................. 20 3.4.4 Horizontal Adjustable Splice Plates ............................................................................. 21 3.4.5 Cable Tray to Box or Floor Splice Plates .................................................................... 21 3.4.6 Offset-Reducing Splice Plates ..................................................................................... 22 3.4.7 Vertical Support Hangers ............................................................................................ 23 3.4.8 Step-Down Splice Plates ............................................................................................. 23 3.4.9 End Plates ................................................................................................................... 23 3.4.10 Single-Rail Cable Tray Fitting Connectors ................................................................ 23 3.5 Fitting Installation ..................................................................................................................... 24 3.5.1 Recommended Support Locations for Fittings ............................................................ 24 3.5.2 Extended Vertical Runs ............................................................................................... 27 3.5.3 Recommended Support Locations for Single-Rail and Wire Mesh Cable Trays ........ 28 3.6 Field Modifications ................................................................................................................... 28 3.6.1 Marking ........................................................................................................................ 28 3.6.2 Cutting ......................................................................................................................... 28 3.6.3 Drilling .......................................................................................................................... 30 3.6.4 Finish Touch-Up .......................................................................................................... 30 3.6.5 Wire Mesh Fittings Fabrication .................................................................................... 31 3.7 Accessories ............................................................................................................................. 31 3.7.1 Barrier Strips ................................................................................................................ 31 3.7.2 Drop-Outs .................................................................................................................... 33 3.7.3 Cable Channel to Cable Tray ...................................................................................... 33 3.7.4 Conduit to Cable Tray Adaptors .................................................................................. 34 3.7.5 Covers and Clamps ..................................................................................................... 34 3.8 Grounding and Bonding........................................................................................................... 36

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NEMA VE 2-2018 Page ii

3.9

3.8.1 Cable Tray Used as an Equipment Ground Conductor (EGC) ................................... 37 3.8.2 Cable Trays with Wire-Type Equipment Grounding Conductor (EGC) Installed ........ 37 3.8.3 Check for Properly Sized EGC or Bonding Jumpers .................................................. 38 3.8.4 How to Install Bonding Jumpers .................................................................................. 40 Bonding to The Metal Frame of the Building and Earth .......................................................... 40

SECTION 4 INSTALLATION OF CABLE .................................................................................................. 41 4.1 General .................................................................................................................................... 41 4.2 Cable Tray Preparation ........................................................................................................... 41 4.3 Cable Pulling Considerations .................................................................................................. 41 4.4 Pulling the Cable ..................................................................................................................... 42 4.5 Fastening Cables ..................................................................................................................... 43 4.6 Protecting Installed Cable........................................................................................................ 44 SECTION 5 MAINTENANCE...................................................................................................................... 45 5.1 Inspection ................................................................................................................................ 45 5.2 Inactive or Abandoned Cables ................................................................................................ 45 5.3 Adding Cables ......................................................................................................................... 45 ANNEX A TYPICAL CABLE TRAY TYPES .............................................................................................. 46 A.1 Cable Ladders ......................................................................................................................... 46 A.2 Single-Rail Cable Trays ........................................................................................................... 46 A.3 Solid-Bottom Cable Trays ........................................................................................................ 47 A.4 Trough (Ventilated Cable Trays) ............................................................................................. 47 A.5 Wire Mesh Cable Tray ............................................................................................................. 47 A.6 Channel Cable Trays ............................................................................................................... 48

TABLES Table 3-1 Fastener Torque ......................................................................................................................... 17 Table 3-2 Maximum Spacing between Expansion Joints that Provide for 250 mm (1 in) Movement.. ...... 19 Table 3-3 Quantity of Standard Cover Clamps Required ........................................................................... 36 Table 3-4 Metal Area Requirements for Cable Tray Systems Used as Equipment Grounding Conductors (NEC Table 392.60(A)) ........................................................................................ 39 Table 3-5 Minimum Size Equipment Grounding Conductors for Grounding Raceway and Equipment (NEC Table 250.122) ............................................................................................ 40

FIGURES

Figure 1-1 Correct Method of Unloading a Truck.......................................................................................... 5 Figure 1-2 Incorrect Method of Unloading a Truck ....................................................................................... 5 Figure 1-3 Correct Method of Unloading a Truck.......................................................................................... 5 Figure 1-4 Incorrect Method of Unloading a Truck ....................................................................................... 5 Figure 3-1 Strut Nut ....................................................................................................................................... 9 Figure 3-2 C-Channel Support ...................................................................................................................... 9 Figure 3-3 Strut Support................................................................................................................................ 9 Figure 3-4 Angle Iron Support ....................................................................................................................... 9

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NEMA VE 2-2018 Page iii Figure 3-5 Typical Strut Support Installation ................................................................................................. 9 Figure 3-6 Strut Support (Exploded View) .................................................................................................... 9 Figure 3-7 Hold Downs ................................................................................................................................. 9 Figure 3-8 Single Cable Tray Hanger Clip .................................................................................................. 10 Figure 3-9 Double Cable Tray Hanger Clip................................................................................................. 10 Figure 3-10 Single Cable Tray Hanger Clip ................................................................................................ 10 Figure 3-11 Flange mount Cable Tray Hanger Clip ................................................................................... 10 Figure 3-12 Wire Basket Tray Hanger Clip ................................................................................................. 11 Figure 3-13 Center Hanger Support ........................................................................................................... 11 Figure 3-14 Center Hanger Support ........................................................................................................... 11 Figure 3-15 Single Channel Hanger ........................................................................................................... 12 Figure 3-16 Double Channel Hanger .......................................................................................................... 12 Figure 3-17 Multiple Splice Support ............................................................................................................ 13 Figure 3-18 Rod through Spine Hanger ...................................................................................................... 13 Figure 3-19 Clevis Hanger .......................................................................................................................... 13 Figure 3-20 Single Strut Cantilever Bracket................................................................................................ 13 Figure 3-21 Gusset Cantilever Bracket ....................................................................................................... 13 Figure 3-22 Fiberglass Cantilever Bracket .................................................................................................. 14 Figure 3-23 Single-Rail Direct Wall Mount .................................................................................................. 14 Figure 3-24 Single-Rail Clamp Wall Mount ................................................................................................. 14 Figure 3-25 Elevated Strut-Type Support ................................................................................................... 14 Figure 3-26 Underfloor Support Attached to Floor Pedestals ..................................................................... 14 Figure 3-27 Single-Rail Floor Support Add Roof Support Examples .......................................................... 15 Figure 3-28 Vertical Threaded Rod Support ............................................................................................... 15 Figure 3-29 Vertical Gusset Cantilever Support ......................................................................................... 15 Figure 3-30 Vertical Strut Support .............................................................................................................. 16 Figure 3-31 Vertical Wall Support .............................................................................................................. 16 Figure 3-32 Horizontal Tray Mount ............................................................................................................. 16 Figure 3-33 Horizontal Support ................................................................................................................... 16 Figure 3-34 Cable Tray Support Locations ................................................................................................. 17 Figure 3-35 Cable Tray Installation ............................................................................................................. 18 Figure 3-36 Cable Tray splice joint Installation ........................................................................................... 18 Figure 3-37 Splice Plate Attachment .......................................................................................................... 18 Figure 3-38 Expansion Splice Plate Attachment ........................................................................................ 18 Figure 3-39 Hold-Down and Guide Clamp Locations ...................................................................