600W clamping on a 256V rail — what the ratings mean
The P6KE300CA-B: With a 256V reverse standoff voltage (the DC or peak-AC voltage the part blocks in normal operation) and a 414V clamping point at the 1.45A peak pulse current (10/1000µs waveform), this TVS sits on a nominal 240VAC or 300VDC bus.
Through-hole DO-15 — repair-bench friendly
The DO-204AC / DO-15 axial leaded package is a through-hole form factor. For a rework lab or MRO bench, this means a technician can desolder and replace the part with standard iron and solder wick — no hot-air station or reflow profile needed. The bulk packaging (loose parts, not tape-and-reel) suits low-volume production runs, prototype builds, or repair stock where a full reel is wasteful. The junction temperature range spans -55°C to 175°C — wide enough for an outdoor telecom cabinet that sees -40°C winter starts or an engine-bay ECU that runs at 125°C ambient. The 175°C upper limit gives margin above typical industrial 85°C or 105°C environments.