The Siemens 6ES7407-0KA01-0AA0 is a SIMATIC S7-400 PS407 power supply that takes universal AC (120/230 V) or DC (110/230 V) mains and delivers 10 A at 5 V DC to the backplane bus.
The 5 V DC rail is the critical one: 10 A capacity with a 200 mA base load required means the power supply won't start delivering to the backplane until it has that minimum draw. If your S7-400 CPU and I/O configuration pulls less than 200 mA on 5 V, the PS407 won't come up — that's a commissioning trap. The 24 V DC rail is idling-proof, so it can run with no load at all. Typical power loss is 29.7 W, which goes as heat into the enclosure. Active power input typ. 105 W. Mains failure hold-up is 20 ms, which is enough to ride through a brief dip but not a full cycle drop. If your line needs ride-through longer than that, you'll need an external UPS or the optional backup battery (2x lithium AA, 3.6 V / 1.9 Ah) to keep the RAM and real-time clock alive. The part carries FM approval up to 40 °C at T4 for hazardous locations.
Mains connection uses 3x 1.5 mm² solid or stranded wire with end sleeve, outer diameter 3 to 9 mm. Equipment protection class I means a protective earth conductor is mandatory — no floating operation. Short-circuit protection is built in, so no external fuse is required on the input, though local code may still demand one. Frequency range is 47 to 63 Hz, covering both 50 and 60 Hz grids globally. Inrush current peaks at 18 A (15x rated input current) for a few cycles — factor that into your mains breaker coordination if multiple supplies power up simultaneously.