What this supply delivers — and what it doesn't
The Siemens 6EP1321-1LD00 is a SITOP PSU100M power supply delivering a rated 3 A at 24 VDC from a universal AC input of 85–264 V, 47–63 Hz. Efficiency sits at 84% under nominal conditions. The 3 A rating holds across 0–3 A at 25 °C ambient; above 50 °C you derate 2.5% per Kelvin up to the 70 °C ceiling — so at 60 °C ambient you're good for about 2.25 A before the internal thermal protection starts to fold back. That's the real-world number for a warm cabinet. Galvanic isolation is safety extra-low voltage (SELV) per EN 60950-1, so the output is safe to touch and suitable for feeding downstream 24 VDC control loads, sensors, and PLCs without an extra isolation barrier. The internal fuse handles primary-side protection; the feeder side wants a 10 A C-curve or 16 A B-curve MCB upstream. Wall-mount only; no DIN-rail clip on this variant.
Clearance and terminal detail
The unit requires 20 mm free air above, left, and right for convection cooling; bottom clearance is 0 mm — it can sit flush on a panel floor or shelf. The screw terminals on the input side accept L, N, and PE conductors from 0.3 to 1.3 mm² single-core or finely stranded. Output side has + and - terminals in the same wire range. That 20 mm top clearance is the critical one — stack another supply or a terminal block directly above and you choke the natural convection path. The bottom-zero clearance is convenient for tight enclosures, but the top gap is non-negotiable if you want the full 3 A at 50 °C.
Carries CE marking, cULus-Listed (UL 508, CSA C22.2 No. 107.1, File E197259), cURus (UL 60950-1, CSA C22.2 No. 60950-1, File E151273), and EAC. Not rated for ATEX, IECEx, DNV GL, FM, or UL hazardous locations — keep it out of classified areas and marine engine rooms unless you have a separate barrier.