ANSI/NEMA WC 51/ICEA P-54-440:2009(R2014)

Foreword
Scope
History
Section 1 - GENERAL INFORMATION
1.1 Background
1.2 References
    1.2.1 Normative References
    1.2.2 Other References
1.3 DEFINITIONS
Section 2 - TABLE DEVELOPMENT PARAMETERS
2.1 Parameters Used to Develop Tray Ampacity Tables
    2.1.1 Cable Operating Temperatures
    2.1.2 Allowable Heat Generation
    2.1.3 Calculated Depth of Cables in Trays - Apparent
          Fill Depth
    2.1.4 Cable Diameters
    2.1.5 Conductor Resistance
    2.1.6 Calculated Free-Air Ampacity
    2.1.7 Ampacity Values
Section 3 - AMPACITY ADJUSTMENT FACTORS
3.1 Correction Factor for Diameters of Cables
3.2 Correction Factor for Temperatures
    3.2.1 Ambient Temperature
    3.2.2 Conductor Temperature
3.3 Correction Factor for Number of Conductors
3.4 Correction Factors for Tray Covers
3.5 Correction Factors for Load Diversity
    3.5.1 Determining the Loading Factor
    3.5.2 Diversity Factors
Section 4 - EXAMPLES
4.1 Calculating Apparent Depth of Cable
4.2 Selecting Ampacity Values and Using Adjustment Factors
4.3 Calculating and Applying Diversity Factors
4.4 Multiple Adjustment Factors
4.5 Calculating Ampacities for Cables Not Covered by Tables
Section 5 - TABLES
5.1 Index to Tables

This Standards Publication covers the ampacity ratings for 600-15,000 volt solid dielectric cables installed in cable trays. Ampacity ratings are tabulated for single conductor cables, triplexed assemblies of single conductor cables, and three-conductor cables incorporating an overall jacket. Ampacities have been tabulated for the cable constructions and the operating conditions normally encountered for tray applications. Correction factors to adjust the tabulated values to better reflect specific conditions are provided. These include adjustments to account for ambient and operating temperatures, cable construction, tray covers, and diversification of the cable loading.