ITAA 1936 s 51(1) or under the depreciation provisions

Income tax: can the cost of plant purchased for a specific project, and fully charged to the client, but which is still held after that project was completed and able to be used again, be treated as fully deductible under subsection 51(1) or under the depreciation provisions of the Income Tax Assessment Act 1936 ?

Income tax: can the cost of plant purchased for a specific project, and fully charged to the client, but which is still held after that project was completed and able to be used again, be treated as fully deductible under subsection 51(1) or under the depreciation provisions of the Income Tax Assessment Act 1936?