7.1 General Provisions

7.1.1 Scope of Application

The requirements specified in this chapter and 26.7 shall apply to non-metallic enclosures and non-metallic components of enclosures related to the explosion-proof type.

Note 1: Some examples of non-metallic components of enclosures related to the explosion-proof type include sealing rings for covers of type "e" or type "t" enclosures, fillers for cable glands of type "d" or type "e", sealing rings for cable glands, seals for switch actuators of type "e", etc.

Note 2: In some supplementary or modified parts of this document, the requirements for "non-metallic components of enclosures" in this chapter apply to non-enclosure components related to the explosion-proof type, such as insulating sleeves of type "d" and terminals of type "e".

7.1.2 Material Requirements

7.1.2.1 General

The documents specified in Chapter 24 shall state the material of the enclosure or enclosure component.

7.1.2.2 Plastic Materials

The technical requirements for plastic materials shall include the following:

a) Name or registered trademark of the resin manufacturer or compounder;

b) Material identification, including model and color;

c) Possible surface treatments, such as varnishing, etc.;

d) Temperature Index (TI) corresponding to the 20,000-hour point on the thermal stability curve, at which point the flexural strength decreases by no more than 50% when tested in accordance with GB/T 11026.1, GB/T 11026.2 and GB/T 9341. If the material does not break in the test before thermal exposure, the temperature index shall be determined based on the tensile strength measured with Type 1A or 1B test pieces specified in GB/T 1040.2. The Relative Thermal Index (RTI-Mechanical Strength or RTI-Mechanical Impact) may be used instead of TI, determined in accordance with ANSI/UL 746B.

e) Where applicable, data support complying with 7.3 (UV resistance).

The data source for the above characteristics shall be determined.

Note 1: This document does not specify requirements for verifying whether plastic materials comply with the manufacturer's technical requirements.

Note 2: When selecting plastic materials, some manufacturers have noted that the type and percentage of fillers, flame retardants, UV stabilizers, etc., have a significant impact on the performance of plastic materials.

Note 3: Guidelines for material traceability can be found in GB/T 3836.21. Manufacturers intending to trace the source of plastics by "fingerprinting" methods (such as infrared scanning or oxygen index) shall pay attention to this during type testing to obtain benchmark information.

7.1.2.3 Elastic Materials

The technical requirements for elastic materials shall include the following:

a) Name or registered trademark of the resin manufacturer or compounder;

b) Material identification, including model and color;

c) Possible surface treatments, such as varnishing, etc.;

d) Continuous Operating Temperature (COT);

e) Where applicable, data support complying with 7.3 (UV resistance).

The data source for the above characteristics shall be determined.

Note 1: This document does not specify requirements for verifying whether elastic materials comply with the manufacturer's technical requirements.

Note 2: When selecting elastic materials, some manufacturers have noted that the type and percentage of fillers, flame retardants, UV stabilizers, etc., have a significant impact on the performance of elastic materials.

Note 3: Guidelines for material traceability can be found in GB/T 3836.21. Manufacturers intending to trace the source of elastic materials by "fingerprinting" methods (such as infrared scanning or oxygen index) shall pay attention to this during type testing to obtain benchmark information.

7.1.2.4 Bonding Materials

The technical requirements for adhesives shall include the following:

a) Name or registered trademark of the adhesive manufacturer;

b) Material identification, including model;

c) Continuous Operating Temperature (COT).

The data source for the above characteristics shall be determined.

Note: This document does not specify requirements for verifying whether adhesives comply with the manufacturer's technical requirements.

7.2 Thermal Stability

7.2.1 Thermal Stability Test

High-temperature resistance tests and low-temperature resistance tests shall be carried out in accordance with 26.8 and 26.9. The test sequence is shown in 26.4.

Reproduction and reprinting by any platform or individual are prohibited!