323. It is prohibited to transport a person in a cage or a skip travelling in a vertical shaft or one inclined more than 60° from the horizontal unless the cage or the skip:(1) moves on guides;
(2) is equipped with safety catches designed to immobilize the cage or the skip operating at the maximum load permitted for the transport of persons, in case of the breaking of the hoisting rope;
(3) is equipped with a protective roof made of sheet steel having a thickness of at least 4 mm (0.2 in) or a material of equivalent strength.
Notwithstanding the foregoing, subparagraph 2 of the first paragraph does not apply to a skip when it is used for inspections and maintenance work in a shaft or of a skip or cage of a friction hoist.