For the program “Connection and Junction Boxes (CJB)- Test Round 2023” the general routine procedure is described by the standard “Explosive atmospheres – Part 7: Equipment protection by increased safety "e"” - IEC 60079-7 Edition 5.1.

A general-purpose connection and junction boxes shall be allocated a rating determined by the method in clause 6.8 to ensure that the limiting temperature not exceeded in service. To simplify the program, a junction box is fitted with the number of 'worst case' terminals that are wired using conductors of the maximum size specified in the datasheet. The maximum current of the junction box should be determined for the temperature class T6 according to IEC 60079-7, clause 6.8 and Annex E. Therefore, the maximum current has been selected as the characteristic of interest which is to be compared in the program “Connection and Junction Boxes (CJB)- Test Round 2023”.

The Test Sample “CJB” is a junction box with outer dimensions measuring 271 mm x 271 mm x 135 mm (L x W x H), see Figure 1. It features 36 feed-through terminals of type Phoenix UT 2,5, along with two end clamps of type CLIPFIX 35-5 securely fastened on mounting rails of type NS 35/15 DIN rail within the Test Sample “CJB”. As specified in the datasheet of the terminal, the conductors with a cross section of 2.5 mm² are selected which is the maximum cross section of a flexible conductor with ferrule. According to the standard IEC 60079-7 (Ed.5.1), clause 6.8, the length of the conductors equals to the maximum internal dimension (three-dimensional diagonal) of 405 mm.

The workload to perform this program is approximately 3 working days.

Detailed information and specifications regarding the test method are described in the “Procedure Instruction of Program “Connection and Junction Boxes - Test Round 2023”” which will be published at a later date.