A safety apparatus for an electrical equipment rack includes a retractable safety device for preventing, when in an operational position, the extending of an extendable rail and an electrical equipment unit mounted thereon from a position internal to the rack to a position external to the rack, and for allowing the same when in a non-operational position. The position of the retractable safety device is linked to the position of a retractable rack support such that when the retractable rack support is lowered in its operative position the retractable safety device is in a non-operational position, and when it is raised in a raised inoperative position the retractable safety device is in an operational position preventing the extending of the extendable rail and an electrical equipment unit mounted thereon to a position external to the rack.