The general rule for employees: expenses: each and every holder: example
An employee who works in a chemical factory is supplied with protective overalls by his employer. However, they are uncomfortable and restrict his movement and so he buys his own overalls to a design approved by his employer. He asks for a deduction for the cost of replacing and washing his overalls, see EIM32465.
No deduction is due. Protective clothing is necessary but is supplied by the employer. He has bought his own overalls of his own volition and this is not an expense that each and every employee in his employment would need to incur, see EIM31640.