An aircraft de-icing system comprising an electrothermal heater comprising first and second dielectric layers (40, 50), one or more conductive lanes, a pair of bus bars for each conductive lane, and a set of strips for each bus bar; wherein: each dielectric layer (40, 50) has a façade section (41, 51) and each conductive lane has a façade section sandwiched between the dielectric façade sections (41, 51), the façade sections (41, 51, 61) span the length of the heater and form the primary heating surface; each conductive lane establishes an electrical path between its lateral ends; each set of strips forms a haven, the haven comprising a floor, a distal wall, a roof, an upper proximal wall above the bus bar, and a lower proximal wall below the bus bar; the first dielectric layer has a haven portion contributing to the formation of the haven, comprising distal side sections (43, 44) that form the haven's distal wall, a ceiling section that forms the haven's roof, and a proximal side section that forms the haven's upper proximal wall, such that the haven portion encloses the distal ends, the proximal ends, and the ceilings of certain strips; each bus bar has a section which projects beyond the proximal walls (38,39) and is adapted for electrical connection to a power source, and a harbor section which resides within the proximal walls (38, 39) and is sheltered within the haven, the harbour section being electrically connected to the respective end of the electrical path; the second dielectric layer has a haven portion including a distal bend section, a ceiling section, and a tail section extending therefrom, wherein the tail section projects outward and is positioned below the bus bar section and functions as an underpinning for the bus bar section when lines are soldered or otherwise electrically connected thereto; and the haven has a sliding decoupling between the bus bar and the haven walls. each dielectric layer (40, 50) has a façade section (41, 51) and each conductive lane has a façade section sandwiched between the dielectric façade sections (41, 51), the façade sections (41, 51, 61) span the length of the heater and form the primary heating surface; each conductive lane establishes an electrical path between its lateral ends; each set of strips forms a haven, the haven comprising a floor, a distal wall, a roof, an upper proximal wall above the bus bar, and a lower proximal wall below the bus bar; the first dielectric layer has a haven portion contributing to the formation of the haven, comprising distal side sections (43, 44) that form the haven's distal wall, a ceiling section that forms the haven's roof, and a proximal side section that forms the haven's upper proximal wall, such that the haven portion encloses the distal ends, the proximal ends, and the ceilings of certain strips; each bus bar has a section which projects beyond the proximal walls (38,39) and is adapted for electrical connection to a power source, and a harbor section which resides within the proximal walls (38, 39) and is sheltered within the haven, the harbour section being electrically connected to the respective end of the electrical path; the second dielectric layer has a haven portion including a distal bend section, a ceiling section, and a tail section extending therefrom, wherein the tail section projects outward and is positioned below the bus bar section and functions as an underpinning for the bus bar section when lines are soldered or otherwise electrically connected thereto; and the haven has a sliding decoupling between the bus bar and the haven walls.