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T able of Contents
Introduction Why Cable Tray?
An In-depth Look at the 2002 NEC, Section 392
Appendix Index & Appendix Sheets Cable Tray Installation & Specification Checklists Footnotes
INTRODUCTION
CABLE TRAY SAFETY FEATURES
WHY CABLE TRAY?
BECAUSE A CABLE TRAY WIRING SYSTEM PROVIDES SAFE AND DEPENDABLE WAYSTO SAVE NOW AND LATER
CABLE TRAY DEPENDABILITY
CABLE TRAY SPACE SAVINGS
CABLE TRAY WIRING SYSTEM COST SAVINGS
DESIGN COST SAVINGS
MATERIAL COST SAVINGS
INSTALLATION COST AND TIME SAVINGS
COST - Cable Tray vs. Conduit
MAINTENANCE SAVINGS
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392.1. Scope.
AN IN-DEPTH LOOK AT 2002 NEC ARTICLE 392 - CABLE TRAY
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Cable Tray Materials
392.2. Definition. Cable Tray System.
392.3. Uses Permitted. Cable tray installations shall not be limited to industrial establishments.
392.3. Uses Permitted. (A) Wiring Methods.
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Establishments.
Establishments. (1) Single Conductor.
392.3(B)(1)(a)
392.3(B)(1)(b)
392.3(B)(1)(c)
Establishment (2) Medium Voltage.
501.4.
502.4.
502.4(B)(3). Nonincendive Field Wiring
503.3.
504.20.
505.15.
392.3. Uses Permitted. (E) Nonmetallic Cable Tray.
392.4. Uses Not Permitted.
392.5. Construction Specifications. (A) Strength and Rigidity.
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392.5. Construction Specifications. (B) Smooth Edges.
392.5. Construction Specifications. (C) Corrosion Protection.
392.5. Construction Specifications. (D) Side Rails.
392.5. Construction Specifications. (E) Fittings.
392.5. Construction Specifications. (F) Nonmetallic Cable Tray.
Typical Cable Tray Layout
392.6. Installation. (B) Completed Before Installation.
392.6. Installation. (C) Supports.
392.6. Installation. (D) Covers.
392.6. Installation. (E) Multiconductor Cables Rated 600 Volts or Less.
392.6. Installation. (F) Cables Over 600 Volts.
392.6. Installation. (G) Through Partitions and Walls.
392.6. Installation. (H) Exposed and Accessible.
392.6. Installation. (I) Adequate Access.
392.6. Installation. (J) Conduits and Cables Supported from Cable Tray.
392.7. Grounding. (A) Metallic Cable Trays.
See Table 250.122 on page 51 for the minimum size EGC for grounding raceway and equipment.
392.7. Grounding. (B) Steel or Aluminum Cable Tray Systems. (1) & (2)
Temperature Rise Test
392.7. Grounding. (B) Steel or Aluminum Cable Tray Systems. (3) & (4)
Cable Tray Label
392.8. Cable Installation. (A) Cable Splices.
392.8. Cable Installation. (B) Fastened Securely.
WARNING!
Use Only As A Mechanical Support For Cables, Tubing and Raceways.
Do Not Use As A Walkway, Ladder, Or Support For Personnel.
392.8. Cable installation. (C) Bushed Conduit and Tubing.
392.8. Cable Installation. (D) Connected in Parallel.
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392.11. Ampacity of Cables Rated 2000 Volts or Less in Cable Trays. (A) Multiconductor Cables.
392.11. Ampacity of Cables Rated 2000 Volts or Less in Cable Trays. (B) Single Conductor Cables.
392.12. Number of Type MV and Type
Trays.
392.13. Ampacity of Type MV and Type
Trays. (A) Multiconductor Cables (2001 Volts or Over).
392.13. Ampacity of Type MV and Type
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CABLE TRAY ACCESSORIES.
FIREPROOFING CABLE TRAY
CABLE TRAY MAINTENANCE AND REPAIR
CABLE TRAY. THERMAL CONTRACTION AND EXPANSION
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Appendix Pages
45
Appendix Sheet 1
TABLE I TEMPERATURE RISE TESTS, CABLE TRAY CONNECTORS, CLASS II ALUMINUM LADDER CABLE TRAY
(See Page 29 - Figure 1 for Temperature Rise Test illustration)
TABLE II TEMPERATURE RISE TESTS, CABLE TRAY CONNECTORS, CLASS II STEEL LADDER CABLE TRAY
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TABLE III TEMPERATURE RISE TESTS, CONDUIT CLAMPS FOR BONDING RIGID CONDUIT TO CABLE TRAY
Appendix Sheet 2
Conduit Clamp DetailTest Set-Up CIRCUIT ARRANGEMENT FOR RIGID CONDUIT TEMPERATURE RISE TESTS
Example - NECSection 392.9(A)(1)
Example - NECSection 392.9(A)(2)
Example - NECSection 392.9(A)(3)
Example - NECSection 392.9(B)
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52
CABLE TRAY SIZING FLOWCHART
Appendix Sheet 8
W Sd (9 max. RS)
Start Here
Sizing Cable Tray Per NEC 392
CABLE TRAY SIZING FLOWCHART
Appendix Sheet 8
Material NEMA Load Depth*
Width Bottom Styles Length Fitting Radius
Tray Series
CABLE TRAY INSTALLATION & SPECIFICATION CHECKLIST
Material Width
Type 0
System Depth*
Width* Rung Spacing* Tiers* Length
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