The ABB OVR T2 1N 40-275S P TS QS is a Type 2 surge protective device (SPD) from the OVR series, designed to clamp transient overvoltages on low-voltage AC power distribution panels. It sits in the main or sub-distribution board, typically on a DIN rail, protecting downstream equipment from switching surges and indirect lightning strikes.
The 40 kA nominal discharge current (In) is the rating that governs its ability to survive repeated surges without degrading — it is the sustained capacity, not just a one-shot maximum. At 275 V AC (Uc) maximum continuous operating voltage, it is sized for 230/400 V TN or TT systems where the line-to-neutral voltage stays under that ceiling. The Type 2 classification (tested with an 8/20 µs waveform per IEC 61643-11) means it is intended for fixed installation at the sub-distribution level, not at the service entrance (Type 1) or at the equipment cord (Type 3).