Abstract: To locate an electric switch relative to a fixed part a bush having a plurality of mating members and a projection in an opening through the bush is positioned in the fixed part. The switch is positioned at one end of a switch carrier having an elongate portion which is also provided with mating members and a projection. The elongate portion is introduced axially into the opening and then rotated to cause the mating members to engage and axially locate the elongate portion in the opening. The projections take up relative positions in which they only permit rotation in the opposite direction to disengage the mating members when sufficient force is applied to deform one or both of the projections.