803271 Intrinsically Safe Rate-of-Rise Heat Detector

The 803271 is an intrinsically safe rate-of-rise heat detector, catalogued as the 803271.EX variant within the Intrinsically Safe and relay products order codes for the S4 Mains Powered Interface Unit. It responds to a rapid rise in temperature rather than a fixed threshold, making it suited to hazardous-area detection served by that interface.

Certification underpins its use in explosive atmospheres: the detector carries Ex ib IIC T4 protection, an ATEX examination certificate from TÜV, and ATEX Group II Category 2G approval when paired with the Zener safety barrier 764744. It also conforms to EN 54-5, holds VdS approval, and is covered by a CE certificate, so the unit meets both functional-safety and hazardous-area requirements.

Physically it is a compact ABS device finished in white, weighing around 110 g and measuring roughly 117 mm across when fitted to its base. It operates across a wide DC supply range and signals an alarm through a flashing red LED. Mounted on detector base 805590, with an optional gasket, it reaches an IP 43 sealing rating, and it supersedes the earlier 802177.