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double wire armoured cable

26 Min Read
South Africa's Witwatersrand Basin contains the deepest operating mines on Earth. Mponeng operates at 3,800 m below surface. South Deep reaches 3,000 m. Driefontein extends to 3,400 m. At these depths, a medium-voltage shaft cable must support its own weight — approximately 13–17 kg per meter for an 11kV 3×120mm² construction — over vertical distances that impose tensile loads exceeding 400 kN on the armour wires at the cable's suspension point. Only SANS 1507 Type 9 double wire armoured (DWA) construction provides sufficient tensile capacity for these depths, and even then, engineering analysis must verify that the maximum free-hanging depth does not exceed the cable's calculated suspension limit. This guide provides the complete engineering framework for that calculation.
Technical Department
on10/03/2026

South African Gold Mines: Maximum Suspension Depth for Type 9 11kV 3×120mm² DWA Shaft CablesComplete Engineering Calculation Guide

South Africa’s Witwatersrand Basin contains the deepest operating mines on Earth. Mponeng operates at 3,800 m below surface. South Deep reaches 3,000 m. Driefontein extends to 3,400 m. At these depths, a medium-voltage shaft cable must support its own weight — approximately 13–17 kg per meter for an 11kV 3×120mm² construction — over vertical distances that impose tensile loads exceeding 400 kN on the armour wires at the cable’s suspension point. Only SANS 1507 Type 9 double wire armoured (DWA) construction provides sufficient tensile capacity for these depths, and even then, engineering analysis must verify that the maximum free-hanging depth does not exceed the cable’s calculated suspension limit. This guide provides the complete engineering framework for that calculation.
4 Min Read
When a Type 8 DWA cable hangs vertically in a mine shaft carrying its full self-weight (typically 10–20 kg per meter), the cable must be secured with cleats at regular intervals to prevent movement, vibration, and sway. However, the traditional approach of simply gripping the cable's outer sheath with mechanical cleats creates a dangerous paradox: sufficient grip force to prevent slip also crushes the delicate insulation layers beneath the sheath. 当Type 8 DWA电缆在矿井竖井中垂直悬挂并承载其全部自重(通常每米10-20公斤)时，必须定期用线夹对电缆进行固定，以防止移动、振动和摇摆。然而，用机械线夹简单地夹紧电缆外护套的传统方法造成了危险的悖论：足以防止滑脱的夹紧力也会压坏外护套下的精细绝缘层。 The Engineering Dilemma: (1) Under-tightened cleats → cable slips under load, creating movement and mechanical fatigue of insulation, eventually leading to internal short circuits. (2) Over-tightened cleats → radial pressure crushes insulation, creating voids and micro-fractures that initiate partial discharge and electrical breakdown.
Technical Department
on06/03/2026

Cleating Guidelines: How to Properly Secure Type 8 6.6kV Vertical Shaft Cables Without Crushing Insulation

When a Type 8 DWA cable hangs vertically in a mine shaft carrying its full self-weight (typically 10–20 kg per meter), the cable must be secured with cleats at regular intervals to prevent movement, vibration, and sway. However, the traditional approach of simply gripping the cable’s outer sheath with mechanical cleats creates a dangerous paradox: sufficient grip force to prevent slip also crushes the delicate insulation layers beneath the sheath. 当Type 8 DWA电缆在矿井竖井中垂直悬挂并承载其全部自重(通常每米10-20公斤)时，必须定期用线夹对电缆进行固定，以防止移动、振动和摇摆。然而，用机械线夹简单地夹紧电缆外护套的传统方法造成了危险的悖论：足以防止滑脱的夹紧力也会压坏外护套下的精细绝缘层。 The Engineering Dilemma: (1) Under-tightened cleats → cable slips under load, creating movement and mechanical fatigue of insulation, eventually leading to internal short circuits. (2) Over-tightened cleats → radial pressure crushes insulation, creating voids and micro-fractures that initiate partial discharge and electrical breakdown.