A double-pole rocker switch with thermal overload protection is constructed as a fully functional sub-assembly which may be tested and adjusted prior to insertion in a tubular housing. The sub-assembly is held in the housing by releasable locks for subsequent servicing. All component elements of the switch are carried on the sub-assembly, including all electrical contacts. In particular, the sub-assembly has a base in which two pairs of electrical contacts are fixedly disposed, each pair being contacted by a spring-loaded contact bridge in one position of the rocker. This position can be attained, however, only if a movable contact block is held at one end by a fulcrum provided by a latch. The latch pivots in a V-shaped groove and may be removed from engagement with the contact block by a bimetallic strip under conditions of overload. In that condition, even deliberate actuation of the rocker cannot result in a closure of the switch because of the absence of the fulcrum.