JB/T 10181.22-2014
Electric cables.Calculation of the current rating.Part 22: Thermal resistance.A method for calculating reduction factors for groups of cables in free air, protected from solar radiation (English Version)

Standard No.

JB/T 10181.22-2014

Language

Chinese, Available in English version

Release Date

2014

Published By

Professional Standard - Machinery

Latest

JB/T 10181.22-2014

Replace

JB/T 10181.4-2000

Scope

This part of JB/T 10181 specifies the calculation method for the current carrying capacity reduction factor of cable groups in free air that are not exposed to direct sunlight. This standard applies to any type of cable or cable group laid flat, as long as all cables have the same diameter and the same loss. This section proposes that the calculation method of allowable ampacity reduction when cables are laid adjacently is limited to a few situations: a) A maximum of 9 cables when laid in a square shape, as shown in Figure 1; b) The number of loops formed by three cables arranged in a triangle The maximum number is 6, including parallel placement to three circuits or double-layer arrangement to two circuits, as shown in Figure 2. Care should be taken when airflow around cables is restricted by adjacent objects. Calculation methods are proposed for the following situations: 　——For a single cable or a circuit laid separately, the ampacity reduction factor of the cable group can be derived from the same type of cable, see 4.1; 　——In the case of no ampacity data, the provided The data uses the formulas of IEC 60287-1-1 and IEC 60287-2-1 to calculate the allowable ampacity of the cable group, see 4.2; 　——In order to avoid a reduction in the allowable ampacity, propose a suitable spacing between cables, see Chapter 5.

JB/T 10181.22-2014 history

• 2014 JB/T 10181.22-2014 Electric cables.Calculation of the current rating.Part 22: Thermal resistance.A method for calculating reduction factors for groups of cables in free air, protected from solar radiation
• 2000 JB/T 10181.4-2000 Calculation of the current rating of electric cables.Part 2:Thermal resistance.Section 2:A method for calculating reduction factors for groups of cables in free air,protected from solar fadiation

JB/T 10181.22-2014 Electric cables.Calculation of the current rating.Part 22: Thermal resistance.A method for calculating reduction factors for groups of cables in free air, protected from solar radiation has been changed from JB/T 10181.4-2000 Calculation of the current rating of electric cables.Part 2:Thermal resistance.Section 2:A method for calculating reduction factors for groups of cables in free air,protected from solar fadiation.