What the 1500W rating means for your rail
The 1.5KE150CA A0G: That 1500W figure is the maximum energy it can absorb in a single transient — above that, the junction fails short. For a 128V nominal rail (reverse standoff voltage), the device starts conducting at 143V minimum breakdown and clamps the surge to 207V maximum at 7.6A peak pulse current.
Through-hole DO-201AA (DO-27) axial package — the leads are 0.96 mm diameter typical, spacing about 8.5 mm. The body is 7.6 mm long, 5.3 mm diameter. It fits standard 0.100-inch pitch breadboard or PTH layouts; the axial leads are trimmed and formed for through-hole soldering. No power line protection (the device is intended for signal and low-voltage DC bus protection, not mains AC).