What it is and what drives the fit
The Siemens 3RT2526-1AG20 is a SIRIUS contactor in the S0 frame size, built for switching motor loads and resistive loads in control panels. The 24 V DC coil pulls 10 A at rated value — that 10 A figure is the make/break capability at 24 V DC, not the AC-3 motor rating, so when you see it on a BOM for a 24 V DC control circuit, this is the contactor that matches. Screw-type terminals on the magnet coil mean no special crimp tooling needed on the line.
Mounting and panel integration
Fastens with screw and snaps onto 35 mm DIN rail per DIN EN 50022. The S0 footprint — 61 mm wide, 85 mm high, 97 mm deep — is the standard size for this current range, so it drops into existing S0 cutouts or rail spacing without re-layout. Mounting position allows ±180° rotation on a vertical surface and ±22.5° tilt forward/backward, which helps when the gland plate or busbar run forces an odd angle. Side clearance to adjacent devices is 6 mm; zero clearance needed upwards, forwards, backwards, or downwards, so you can pack it tight on the rail vertically.
Switching capability and thermal limits
The contactor carries auxiliary switch capability — useful for status feedback or interlocking without an add-on block. Mechanical life typical at 10,000,000 operations. Operating temperature range -25 to +60 °C; storage range -55 to +80 °C. The arcing time sits at 10 ms — fast enough for most PLC-driven cycles, but if your load has a long inductive tail, verify the switching frequency: at DC it's rated 1,500 1/h, at AC-1 maximum 1,000 1/h. Those are the thermal limits, not the mechanical ceiling.