The universal voltage power pack (UVPP) is a self-contained transformer and relay designed for low voltage 24 VDC occupancy sensors. The power pack supports and automatically detects the line voltage input within the 100 to 277 VAC range. This eliminates the need for voltage specific power packs. The universal voltage power pack with manual ON/Off control (UVPPM) provides a unique solution for lighting applications where users require both manual ON/off control as well as automatic off control. Both power packs are capable of switching 20 A loads and feature zero arc point switching, minimizing relay contact wear from high inrush loads. A single power pack can power either 4/3 sensors and the MPSA auxiliary relay for multiple circuits. The power packs are plenum rated and easily mount inside or outside of a junction box or inside a fixture.