Stress grading mastic is used to fill air voids between the ferrule, conductor, insulation and stress control tube to remove or eliminate electrical discharges around the connector area . Stress grading mastic also provide smooth surface for stress control tubes and distribute the voltage evenly around the connector. To cover the sharp edges of armour and other metallic parts and provide cushion.
| CHARACTERISTIC | TYPE OF TEST | REQUIREMENT | TEST METHOD |
|---|---|---|---|
| PHYSICAL PROPERTIES | |||
| Colour | Routine | Brown | Visual |
| Dimensions | Routine | W 1 :25+ 5 | Measurement |
| Needle penetraton | Routing | 25(Min.) | ASTM E - 5 |
| Softening Point | Routing | 125 c(Min.) | ASTM E - 28 |
| Packing | Routing | Packed in Release | Visual |
| MECHANICAL PROPERTIES | |||
| Shear strength | Routine | 3 N/Sq.cm(Min.) | TP/QA/63 |
| Elongation | Routine | 75% width reducing with out breakage | Tensile Test |
| ELECTRICAL TEST | |||
| Volume resistivity | Routine | 1 * 10 ohm cm(Min.) | ASTM D 257 |