(e) Safety. Elevator cars suspended by wire ropes or chains shall be provided with a car safety capable of stopping and sustaining the car with contract load, as follows:
- (1) The car safety shall be of a type operated as the result of the breaking of the suspension means, or by a speed governor. If of the speed governor type, it shall operate to set the safety at a maximum speed of 175 feet per minute, except that on breaking the hoist ropes, the safety shall operate without appreciable delay and independently of the governor speed action.
- (2) If a speed governor is used, it shall be located where it is not struck by the car or counterweight in case of overtravel and where there is sufficient space for full movement of the governor parts.
- (3) The motor control circuit and the brake control circuit shall be opened before or at the same time the safety applies.
- (4) The governor cable shall be of iron, steel, monel metal or phosphor bronze, not less than 1/4 inch in diameter. Tiller rope construction shall not be used for governor ropes.
- (5) Elevators of the winding drum type with wire rope suspension shall be provided with a slack rope device of the manually reset type which cuts off the power and stops the elevator machine if the car is obstructed in its descent and the hoist ropes slacken. When the car is suspended by chains, slack chain devices shall be provided which cut off the power and stop the elevator machine if the car is obstructed in its descent and the suspension chains slacken. This device is not required to be of the manually reset type if the chain sprockets are guarded to prevent the chain from jumping off the sprockets.
- (6) No safety device which depends upon the completion and maintenance of an electric circuit for the application of the safety shall be used. Car safeties shall be applied mechanically. Cast iron shall not be used in the construction of a car safety when its breakage might result in the failure of the safety to function to sustain the car.