The Siemens 6EP3436-8MB00-2CY0 is a SITOP PSU8600 DIN rail power supply rated for 20 A continuous output at 25 °C ambient, split across four individually configurable outputs. This is not a single-output brick — the four outputs let you distribute 24 VDC to separate loads (PLC, I/O, field sensors, actuators) with individual current limiting per channel. The 20 A total is the ceiling; each output is rated 5 A, so the sum of all four channels cannot exceed 20 A. Input voltage range is 400-500 VAC three-phase, 50/60 Hz, with a derating window between 320-360 V and 530-575 V. That means it is designed for European 400 V three-phase networks and North American 480 V systems — common in machine tool and conveyor applications where a stable 24 VDC bus is critical.
Derating and thermal budget
Above 50 °C ambient the unit derates at 2.5% per Kelvin, so at 60 °C the available output drops to roughly 15 A. No derating applies when paired with the CNX8600 expansion module and total load stays under 240 W. This is the number that governs real panel placement — if the supply sits next to a drive or transformer in a sealed enclosure, the derating curve determines whether 20 A is actually available. Storage and transport range is -40 to +85 °C. MTBF at 40 °C is 243,178 hours.
DIN rail mounting and connectivity
The input side uses plug-in terminals with one screwed connection each for, L3, and PE, accepting 0.2-4 mm² wire. The output side has two plug-in terminal blocks: terminals 1-2 and 3-4 each have two screwed connections for 0.2-2.5 mm², and the 0 V terminal has three connections for up to 4 mm². This terminal layout allows daisy-chaining the 24 VDC bus to multiple loads without extra distribution blocks. PROFINET protocol support is built in — the PSU8600 series communicates over PROFINET for monitoring and configuration, not just power delivery. The unit provides galvanic isolation with safety extra-low output voltage per EN 60950-1 and EN 50178.
Approvals and lifecycle
The feeder requires a 3-pole miniature circuit breaker 6-16 A characteristic C, or a Siemens 3RV2011-1DA10 (setting 3 A) or 3RV2711-1DD10 (UL 489). Maximum I²t value is 1.2 A²·s — relevant for fuse coordination in the upstream protection.