Abstract: The invention relates to a quick-fixing device on electrical installation equipment, in particular, on a power breaker, residual current circuit breaker, or similar, for clipping the same to a standard profile rail in particular a top-hat rail, whereby the electrical installation equipment comprises a recess on the fixing side with a fixed lug arranged on a wall of the recess and a moving lug permanently pressed inwards against a spring force in the direction of a wall, said lug engaging in the assembled state behind the longitudinal edge of the free arm of the top-hat rail. The sprung lug is moulded to a bar, connected in one-piece to the installation equipment by at least one sprung connector web.