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IS 10810 Part 23 Enviromental Stress Cracking Test

. Scope - Covers the procedure of test for cracking due to environmental stresses on electric jolyethylene insulation or sheath of cables.

!. Significance - Certain polar liquids, such as greases and lubricants, when come in contact vith either polyethylene sheath or insulation cause cracks. This phenomenon is termed as environmental stress cracking and the degree of cracking is dependent on melt flow index of the lolyethylene compound used. This test indicates whether correct grade of polyethylene compound las been used or not.

1. Terminology - See IS : 1885 ( Part 32)-1971 'Electrotechnical vocabulary : Part 32 Cables,

:onductors and accessories for electricity supply'.

I. Apparatus

I.1 Hard Glass, Tesf Tube - 200 mm long and 32 mm in diameter closed by suitable means, such as :ork covered with aluminium foil.

1.2 Specimen Holder - In accordance with Fig. 1.



5. Material

5.1 The Cracking Agent - Nonyl phenoxy poly-oxyethylene ethanol.

6. Test Specimen - Samples, 1'0 m long, shall be taken from the completed cable. Three tesj specimens, approximately 40 mm long, 12.5 mm wide and 3 mm thick, shall be moulded from eact sample. A slit, approximately 20 mm long and 0.5 to 0.6 mm deep, shall be made in the centre o' one of the 40 mm x 12.5 mm surface of each specimen,

7. Conditioning - No conditioning of the specimen is required for this test.

8. Procedure

8.4 The specimens shall be bent with the slit on the outside and placed in a test tube. The cracking agent shall be added to completely cover the specimen.

8.2 The test tube shall be closed by suitable means, such as cork covered with aluminium foil, and placed in an oven at a temperature of 50 f 2°C for 48 hours. At the end of this period, the

;F;;cirens shall be removed, allowed to cool to room temperature and then observed for any

8. Tabulation of Observation

Sample No. Observation

r--*-_-7

Cracks/No Cracks

1.

2.

3.

10. Calculation - No calculation is involved.

11. Report

11 .l Environmental stress cracking for polyethylene

Reference specification

Sample No. Observation

~"-A----~

Cracks/No Cracks

1.

2.

3.

11.2 Conclusion - Specimen meets/does not meet the requirements of the specification.

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