wire, cable & conduit

Engineering EncyclopediaSaudi Aramco DeskTop Standards

EVALUATING ABOVE-GRADE WIRE, CABLE, AND CONDUIT INSTALLATIONS

Note: The source of the technical material in this volume is the Professional Engineering Development Program (PEDP) of Engineering Services. Warning: The material contained in this document was developed for Saudi Aramco and is intended for the exclusive use of Saudi Aramcos employees. Any material contained in this document which is not already in the public domain may not be copied, reproduced, sold, given, or disclosed to third parties, or otherwise used in whole, or in part, without the written permission of the Vice President, Engineering Services, Saudi Aramco.

Chapter : Electrical File Reference: EEX-206.02

For additional information on this subject, contact PEDD Coordinator on 874-6556

Engineering Encyclopedia

Wire and Cable Systems Evaluating Above-Grade Wire, Cable, and Conduit Installations

CONTENT

PAGE

INTRODUCTION............................................................................................................. 4 ABOVE-GRADE INSTALLATION TECHNIQUES: CONDUIT, CABLE TRAYS, AND EXPOSED CABLE ....................................................................................... 5 Conduit ................................................................................................................. 5 Rigid Steel ................................................................................................. 6 EMT ........................................................................................................... 7 Flexible Liquid-Tight................................................................................... 8 Cable Trays: Design, Construction, and Usage Requirements........................... 8 Aluminum................................................................................................... 9 Fiberglass ................................................................................................ 10 Exposed Cable: Uses and Routing Requirements............................................. 11 Metal-Clad/Armored................................................................................. 11 Routing Requirements ............................................................................. 12 DETERMINING CABLE TRAY INSTALLATION REQUIREMENTS.............................. 13 Loading............................................................................................................... 14 Magnetic Heating Effects.................................................................................... 18 Circuit Separation ............................................................................................... 19 Grounding and Bonding Requirements and Methods........................................ 22 Tray Separation .................................................................................................. 23 Supports/Fastenings........................................................................................... 24 Tray Routing/Protection Covers.......................................................................... 26 Fittings, Bends, and Drops ................................................................................. 27 DETERMINING CONDUIT INSTALLATION REQUIREMENTS.................................... 28 Conduit Types and Applications ......................................................................... 28 Conduit Sizing and Routing ................................................................................ 30 Conduit Fill............................................................................................... 30

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Engineering Encyclopedia

Wire and Cable Systems Evaluating Above-Grade Wire, Cable, and Conduit Installations

Jam Ratio................................................................................................. 32 Cable Clearance Within the Conduit ........................................................ 33 Magnetic Heating Effects ......................................................................... 34 Conduit Clearances ................................................................................. 34 Fire Proofing ............................................................................................ 34 Conduit Bending ................................................................................................. 35 Minimum Bending Radii ........................................................................... 35 Conduit Threading .............................................................................................. 36 Indoor and Outdoor Conduit Terminations ......................................................... 38 Fittings ..................................................................................................... 38 Seals (Explosion Proof) ........................................................................... 39 Expansion Joints...................................................................................... 40 Conduit Supports................................................................................................ 40 DETERMINING CABLE PULLING REQUIREMENTS .................................................. 43 Rigging Procedures ............................................................................................ 43 Pulling Grips ............................................................................................ 47 Pulling Lines ............................................................................................ 48 Duct Lubricating....................................................................................... 49 Cable Pulling Parameters ................................................................................... 50 Maximum Pulling Tensions ...................................................................... 50 Sidewall Pressure .................................................................................... 64 Rigging Method Effects Calculation ......................................................... 68 DETERMINING HAZARDOUS AREA WIRING AND SEALING REQUIREMENTS ...... 73 Wiring ................................................................................................................. 74 Conduit Sealing .................................................................................................. 77 Cable Sealing ..................................................................................................... 80 List of Figures

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Engineering Encyclopedia

Wire and Cable Systems Evaluating Above-Grade Wire, Cable, and Conduit Installations

Figure 1: Aluminum Cable Tray Load/Span Class Designation (from NEMA VE-1) ..... 15 Figure 2: Fiberglass Cable Tray Load/Span Data (from NEMA FG-1) ......................... 16 Figure 3: Fiberglass Cable Tray Temperature Correction for Allowable Working Load (from NEMA FG-1).................................................... 17 Figure 4: Minimum Circuit Separation Distances for Signal Cabling in Cable Tray (from SAES-J-902) ............................................. 21 Figure 5: Conduit Sizing Requirements........................................................................ 31 Figure 6: Allowable Percentage of Conduit Fill (from NEC, Chapter 9) ........................ 32 Figure 7: Required Dimensions of Conduit Threads (from UL 6) ................................. 37 Figure 8: Maximum Distance Between Rigid-Metal Conduit Supports ......................... 42 Figure 9: Dynamometer Used to Measure Pulling Tension .......................................... 45 Figure 10: Basket Grip on Cable .................................................................................. 47 Figure 11: Pulling Eye on Cable ................................................................................... 48 Figure 12: Cable Configurations................................................................................... 53 Figure 13: Vertical Conduit Bends................................................................................ 59 Figure 14: Example Pulling Tension Calculation............................................................. 61 Figure 15: Sidewall Pressure on Cable During a Pull...................................................... 65 Figure 16: Inside Radius of Standard Conduit Elbows.................................................... 67 Figure 17: Sample Rigging Methods Effects Calculation ................................................ 68

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Engineering Encyclopedia

Wire and Cable Systems Evaluating Above-Grade Wire, Cable, and Conduit Installations

INTRODUCTION In order to evaluate various types of approved Saudi Aramco above-grade wire, cable, and conduit installations for applicability of use, the Participant must have a thorough understanding of the types of installation techniques that are available, the minimum requirements of the various governing documents for each type of installation, and the methods that are used to determine the installation requirements for each type of installation. The cable installation methods that are described in this Module (e.g., cable trays and above-ground conduit) are all used for the same reason: to install cable so that the cable will function safely and adequately throughout its projected operating life. As such, the optimal cable installation method should be selected for the facility installation. The optimal cable installation method is selected through an evaluation of the specific cable installation requirements, installation topography, and the installation method cost. In addition to the abo