This unit is a water resistant switching type voltage converter intended for use on vehicles with a 12V electrical system to power accessories designed for use on a 24V vehicle. The unit can deliver 12A continuous and 15A intermittent output load current and has output overload and over temperature protection with a fully automatic reset. The unit 12V input and 24V output negatives are galvanically isolated. The unit is assembled in an aluminium extruded case and features a high efficiency converter, with thermal protection. The extruded aluminium case and the fact that the unit is encapsulated in silicon rubber allows for reliable operation in harsh vehicle environments and areas of high ambient temperatures. This unit is available with suffix P to meet Institute of Petroleum DOC - 1.92.1 for use on hazardous vehicles.