An inertia switch assembly comprises an inertia switch assembly element encapsulated by potting material within a housing. The inertia switch assembly element comprises a non-magnetic enclosure containing an inertial mass and switch contacts. The switch contacts are connected by conductors that become terminals parallel with and spaced radially of the enclosure as they pass through an aperture in the housing. This aperture is closed by a closure on the terminals. Potting material is kept from intruding into the enclosure by a sealed closure which closes an open end of the enclosure and through which the conductors pass. The housing has an integral shroud surrounding the terminals to thereby form a connector plug structure for connetion with a mating connector plug structure leading to a circuit controlled by the switch assembly. The housing also has a triangular-shaped base containing apertures at each apex to provide for attachment of the housing to a wall. The inertial mass is magnetically biased by a magnetic circuit which includes an axially slotted tube disposed around the switch assembly element.
