What the 548V clamp means for your rail
The 1.5KE400A-T: With a reverse standoff of 342 V and a minimum breakdown of 380 V, it protects a 342 V DC bus or a 240 V AC rectified line from surges up to 1500 W peak pulse power.
Through-hole DO-201 — field-swappable
The DO-201AA (DO-27) axial package is a through-hole form factor that can be swapped on site with basic hand tools — no hot-air station needed. The body is clearly marked with the polarity band, so orientation is obvious even under a panel light.