The universal voltage power pack (UVPP) is a self-contained transformer and relay designed for low voltage 24VDC occupancy sensors. The power pack supports and automatically detects the line voltage input within the 100-277VAC 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 20A loads and feature zero arc point switching, minimizing relay-contact wear from high inrush loads. A single power pack can power either 4 sensors or 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.