A mounting device for removably supporting an overflow safety switch in operable position within a condensation collecting drain pan in HVACR equipment. The mounting device includes a clip member that is secured to the drain pan side wall and locked in place by a non-penetrating thumb screw. A bracket removably attaches to the overflow safety switch at several adjusted positions and is slidably adjustable on the clip member for adjustably positioning the overflow safety switch relative to a bottom of the drain pan. The overflow safety switch is easily removed from the bracket for adjustment and replacement while the bracket remains fitted to the clip member. Moreover, the bracket is easily removed from the clip member without removing the clip member from the drain pan side wall.