The OVRT23L40150PTSU is a 3-pole surge protection device (SPD) on a DIN-rail footprint, rated for a 40 kA maximum discharge current and a service voltage of 240/120 V split-phase or 208/120 V wye. The 40 kA interrupt rating means it can safely divert a surge of that magnitude to ground without failing open or shorting — the key number for coordinating with downstream equipment. An integral auxiliary contact gives the panel or BMS a dry-contact signal for remote monitoring of the SPD's status.
The 3-pole block occupies three module widths; leave clearance above and below for the discharge vent path. The auxiliary contact terminals are typically wired to a PLC digital input for remote health monitoring — no separate relay needed.