What the 1.5SMCJ90C does on a board
The 1.5 kW peak rating tells you this is a secondary-protection device, not a power-line protector — it sits behind the bulk clamp and catches whatever slips past. Power line protection is flagged No in the listing, which means you would not hang this directly on a 90 V nominal line without pre-isolating the surge energy upstream.
Clamp envelope and thermal margin
The 160 V clamping ceiling at 9.4 A is a single-point spec; the Vc curve in the datasheet shows how the clamp voltage rises with higher peak currents, which matters if the surge environment produces >9.4 A pulses.