How should the division between owner-supplied materials and contractor-supplied materials be made?

How should the division between owner-supplied materials and contractor-supplied materials be made?

Core equipment (chillers, transformers, elevators, generators) is recommended to be supplied by the Client to ensure traceability of quality; general materials (wires and cables, pipes, fans) may be supplied by the Contractor, but the Client must approve the quality and price. The contract shall specify the wastage rate of Client-supplied materials.