The OFU 1 was developed specifically for our client, as a turnkey project for an application with a UPS system. The OFU1 is an Ex o, oil filled power resistor. The main body is stainless steel, with an Aluminium alloy cover. An Ex e terminal enclosure is provided to enable segregation from the oil filled compartment, for convenient termination of external cables. The unit has a sight glass for checking the oil level. Due to the power dissipation and relatively high surface temperature, oil immersion has been adopted as the type of explosion protection. The project was completed in 12 weeks from concept, to build, and ATEX certification. Notified Body Element (formerly TRL) witnessed all compliance tests at our works and issued a Unit Verification Certificate.