Covered conductor tenders and datasheets use a mix of conductor, insulation and hardware terms, and the same term is sometimes used loosely. This glossary defines the terms a buyer meets when specifying medium voltage covered conductor (MVCC), so that the specification, the quotation and the test certificate all refer to the same thing.
| Term | Meaning in a covered conductor specification |
|---|---|
| Covered conductor (MVCC) | A stranded overhead conductor with a semi-conducting screen and insulating layers extruded over it. The covering limits the faults caused by brief contact with branches, other phases and animals. It is not rated as a full insulated cable, so the line is still supported on insulators and clamps. |
| AAAC | All aluminium alloy conductor. One of the four core types APAR lists for covered conductor. |
| ACSR | Aluminium conductor steel reinforced. Aluminium strands over a steel core that carries much of the mechanical load. |
| ACSS | Aluminium conductor steel supported. Annealed aluminium strands over a steel core, used where the conductor operates at higher temperature. |
| AL59 ACS | The high-temperature core option on the APAR page, rated up to 105°C against up to 95°C for the other core types. |
| Longitudinally water-tight conductor | A stranded conductor built so that water cannot travel along the strands if the covering is damaged. |
| Semi-conducting screen | The layer between the conductor and the inner insulation. It smooths the electric field at the conductor surface. |
| Inner insulation | The XLPE layer over the screen, described on the APAR page as carbon free. |
| Outer insulation | The UV-protected, anti-tracking black layer of XLPE or HDPE on the outside. |
| Tracking | The formation of a conductive path across an insulating surface under contamination and moisture. An anti-tracking outer layer is designed to resist it. |
| Span | The horizontal distance between two supports on the line. |
| Sag | The vertical drop of the conductor below the line joining its two supports. Sag and tension together set ground clearance. |
| Messenger wire | A separate supporting wire that carries the load of a bundled or spacer cable system. Covered conductor is self-supporting and does not need one. |
| Rated tensile strength (RTS) | The breaking load of the conductor as declared in the datasheet, used to set the permitted working tension. |
| Ampacity | The current a conductor can carry continuously without exceeding its rated temperature. |
| Suspension clamp | The fitting that holds the conductor on an intermediate support. |
| Anchoring (dead-end) clamp | The fitting that takes the full line tension at the end of a run or at an angle. |
| Insulation-piercing connector | A connector whose teeth pierce the covering to make contact with the conductor, so the covering does not need to be stripped. Types listed by APAR are covered-to-covered, bare-to-covered and tapping. |
| Arc protection device | A fitting that holds a fault arc away from the conductor so that the arc does not burn through it at a fixed point. |
| Type test and routine test | A type test proves a design once. A routine test is carried out on production. A certificate should state which one it records. |
Standards named on the APAR page
The product page lists SS-EN 50397-1 for the covered conductor, with BS EN 50182, IS 398 Part 2 and Part 4 and IEC 61089 for the conductor, and EN 50397-2 for the accessories. The page advises confirming the applicable standard against the project tender. The covered conductor selection guide and the core options comparison use these terms in context.