DC Switching Capacity — the Real Selection Number
The 3RT2518-1BJ80 is a Size S00 SIRIUS contactor from Siemens, and its DC switching ratings are the numbers that decide the fit for most control circuits. At 24 VDC it switches 10 A; at 48 V and 60 V that drops to 2 A, and at 220 VDC it handles only 0.3 A. The 400 VDC rating is 3 A, and at 600 VDC it's down to 0.1 A. That steep derating curve is typical for DC switching — the arc extinguishes less readily than AC, so the contact gap and blowout design govern the maximum current at each voltage. If your BOM calls for switching a 48 VDC solenoid or a 125 VDC brake coil, this contactor's 2 A rating at those voltages is the figure to check against your load's inrush and holding current.
Mounting and Panel Integration
Fastens by screw or snaps onto 35 mm DIN rail per DIN EN 50022. The mounting position is flexible — ±180° rotation on a vertical surface, plus ±22.5° tilt forward or backward. Side-by-side mounting is permitted with zero clearance on all sides (0 mm upwards, forwards, backwards, downwards), and 6 mm at the side. The 45 mm width and 57.5 mm height fit standard panel layout grids. Depth is 73 mm, which clears most enclosure back-panel depths without interference.
Termination and Wiring
Both the main current circuit and the magnet coil use screw-type terminals. The solid or stranded wire capacity is 2x (0.5 to 1.5 mm²), 2x (0.75 to 2.5 mm²), or 2x 4 mm² — enough for control wiring up to 12 AWG. An auxiliary switch is included on the contactor.
Environmental and Lifecycle
Operating temperature range is -25 to +60 °C; storage range is -55 to +80 °C. The contactor is rated for 30,000,000 typical mechanical operations. Electrical life at AC-1 is 1,000,000 operations at maximum switching rate, and at AC duty the maximum switching frequency is 10,000 cycles per hour.