40 A, 4 outputs — the load-distribution decision
The 6EP3437-8MB00-2CY0 is a 40 A rated DIN rail power supply from the SITOP PSU8600 family, delivering that current across 4 individually configurable outputs. Each output is rated 10 A, so you can split the total load across four circuits — useful when you need to isolate control logic from field actuators or feed separate sub-panels from a single supply.
Derating and thermal budget
Full 40 A output is available from 0 to 40 °C ambient. Above 50 °C, derate 2.5 % per K up to 60 °C max operating ambient. No derating when paired with the CNX8600 expansion module, provided total output load stays under 480 W. The unit is convection-cooled — no fan to fail, but the 50 mm clearance above and below the DIN rail is non-negotiable for airflow. Stacking modules tighter than that will push internal temperatures above the derating curve.
Input range and feeder protection
Input voltage range is 400 to 500 V AC, 3-phase, 47 to 63 Hz. Below 360 V and above 530 V the unit derates. Siemens specifies a 3-pole miniature circuit breaker 10-16 A, characteristic C, or a circuit breaker 3RV2011-1DA10 (setting 3 A) in the feeder. The I²t rating is 2.24 A²·s.
cULus-Listed to UL 508 and CSA C22.2 No. 107.1 (file E197259), plus cCSAus to UL 60950-1 and CSA C22.2 No. 60950-1. Also carries CE and EAC marking. No ATEX or IECEx — this is a standard industrial supply, not for hazardous locations. Galvanic isolation provides SELV output per EN 60950-1 and EN 50178 — safe to touch and suitable for feeding 24 V DC control circuits without extra isolation transformers.