A surface-mountable electronic PTC device, comprising: an active polymer layer laminated between a first electrode and a second electrode to form an active layer laminated sheet structure, the active polymer layer being subject to thermal expansion; a first insulation layer on the first electrode and a second insulation layer on the second electrode; first and second conductive surface mount terminals (346, 348) formed only on an exposed surface of the second insulation layer; a first cross-conductor electrically connecting the second electrode and the first surface mount terminal, and separated from the first electrode by a portion of the first insulation layer, which portion forms a first isolation area; and a second cross-conductor electrically connecting the first electrode and the second surface mount terminal, and separated from the second electrode by a portion of the second insulation layer, which portion forms a second isolation area; wherein said first cross-conductor is continuous with a first anchor pad formed from a first metallization layer on an exposed surface of the first insulation layer; wherein said second cross-conductor is continuous with a second anchor pad formed from a first metallization layer on an exposed surface of the first insulation layer; and wherein each of said first anchor pad and said second anchor pad occupies a surface area on the first insulation layer which is smaller than the surface area occupied by said first or second conductive surface mount terminal (346, 348) on said second insulation layer so as not to restrain the thermal expansion of the active polymer layer. an active polymer layer laminated between a first electrode and a second electrode to form an active layer laminated sheet structure, the active polymer layer being subject to thermal expansion; a first insulation layer on the first electrode and a second insulation layer on the second electrode; first and second conductive surface mount terminals (346, 348) formed only on an exposed surface of the second insulation layer; a first cross-conductor electrically connecting the second electrode and the first surface mount terminal, and separated from the first electrode by a portion of the first insulation layer, which portion forms a first isolation area; and a second cross-conductor electrically connecting the first electrode and the second surface mount terminal, and separated from the second electrode by a portion of the second insulation layer, which portion forms a second isolation area; wherein said first cross-conductor is continuous with a first anchor pad formed from a first metallization layer on an exposed surface of the first insulation layer; wherein said second cross-conductor is continuous with a second anchor pad formed from a first metallization layer on an exposed surface of the first insulation layer; and wherein each of said first anchor pad and said second anchor pad occupies a surface area on the first insulation layer which is smaller than the surface area occupied by said first or second conductive surface mount terminal (346, 348) on said second insulation layer so as not to restrain the thermal expansion of the active polymer layer.