The project specification, agreed between G Corner and the client, focused on a number of key thermal and electrical performance areas: temperature rise across the busbar system, operating current density, and steady-state voltage drop under maximum load.

Allowable conductor temperature rise was set in accordance with BS 159. The feeder system across both cell-rooms was designed to suit a maximum capacity rating of 54 kA and 176 VDC, with sufficient margin for harmonic content and ambient swing in the Zambian climate.

Each cell-room was built around a copper short main-trunk feeder, a copper long main-trunk feeder, and a copper crossover trunk section linking the two electrolyser lines. The crossover gives the operator the option to isolate, balance, or reroute current between rectiformer outputs without taking the full cell-room offline.

Section sizes were tuned so that each individual main-trunk feeder delivered an effective current density rating of 1.054 A/mm² at the plant’s maximum capacity — well inside the BS 159 thermal envelope, leaving headroom for over-load events and future capacity creep.

Shorting frames for the project were designed to enable the simultaneous electrical isolation of two electrowinning cells for routine maintenance — a critical operability win for a continuous-process plant of this size.

Frames were manufactured from high-conductivity copper. The mechanical design is a convection air-cooled rectangular frame, fitted with copper flexible spring-loaded contacts. The result is a rigid construction with optimum anode/cathode self-adjusting contact pressure, even after thermal cycling.