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Siemens 3RT2018-2BW42 — Contactors

Siemens 3RT2018-2BW42 SIRIUS Power Contactor, 48 VDC Coil, S

MPN3RT2018-2BW42
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Siemens SIRIUS 3RT2018-2BW42 power contactor, Size S00, 48 VDC coil, spring-type terminals, 45 mm wide, 70 mm height, 73 mm depth.

Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Jul 2026

Specifications

3RT2018-2BW42 — Identification
ParameterValue
Contactor frame sizeS00
3RT2018-2BW42 — Ratings & Performance
ParameterValue
Rated operational current, AC-12, max.10 A
Rated operational current, AC-4 @ 400 V11.5 A
Rated value @ 400 V3 A
Rated value @ 500 V2 A
Rated value @ 690 V1 A
Rated value @ 230 V2 hp
Rated value @ 24 V10 A
Rated value @ 60 V2 A
Rated value @ 110 V1 A
Rated value @ 220 V0.3 A
3RT2018-2BW42 — Control & Coil
ParameterValue
Control supply voltage typeDC
3RT2018-2BW42 — Contacts & Poles
ParameterValue
Main poles3
Main NO contacts3
Auxiliary contact reliability1 faulty switching per 100 million (17 V, 1 mA)
3RT2018-2BW42 — Protection & Coordination
ParameterValue
Short-circuit coordination type 1, fusegG: 50A (690V,100kA), aM: 25A (690V,100kA), BS88: 50A (415V,80kA)
Short-circuit coordination type 2, fusegG: 25A (690V,100kA), aM: 20A (690V,100kA), BS88: 25A (415V,80kA)
Aux. switch short-circuit protection, fusegG: 10 A (500 V, 1 kA)
3RT2018-2BW42 — Connection & Mounting
ParameterValue
Main circuit connectionspring-loaded terminals
Aux. / control circuit connectionspring-loaded terminals
Conductor cross-section, solid0.5 ... 4 mm²
Conductor cross-section, solid or stranded2x (0,5 ... 4 mm²)
Conductor cross-section, finely stranded w/ ferrule2x (0.5 ... 2.5 mm²)
Mounting methodscrew and snap-on mounting onto 35 mm standard mounting rail according to DIN EN 60715
Side-by-side mountingYes
3RT2018-2BW42 — Durability
ParameterValue
Durability (operating cycles, typ.)30 000 000
Durability with aux. switch block (cycles, typ.)10 000 000
3RT2018-2BW42 — Environmental
ParameterValue
Operating temperature range-25 ... +60 °C
Storage temperature range-55 ... +80 °C
Installation altitude, max.2 000 m
3RT2018-2BW42 — Mechanical
ParameterValue
Width45 mm
Height70 mm
Depth73 mm

Product details

The spring-type terminals accept solid or stranded conductors from 0.5 to 4 mm², and the operating temperature range of -25 to +60 °C covers most indoor industrial environments without derating concerns.

The 48 VDC coil is the control voltage you need to supply; the contactor pulls in reliably at 0.8 of rated voltage (38.4 V) and holds in. The auxiliary contact ratings are given per voltage: 10 A at 24 V, 2 A at 48 V and 60 V, 1 A at 110 V, 0.9 A at 125 V, 0.3 A at 220 V, and 3 A at 400 V — these are the switching capacities for the built-in auxiliary switch, not the main poles. Switching frequency limits are duty-dependent: up to 1000 operations per hour for AC-1 resistive loads, 750/h for AC-2 and AC-3 motor starting, and 250/h for AC-4 plugging/reversing. The AC-3e rating also caps at 750/h. These numbers govern contact life; exceeding them accelerates wear.

Frequently asked questions

What is the closest functional alternative to 3RT2018-2BW42?

The closest functional sibling is 3RT2016-2BB42-ZX95. Both are Size S00 SIRIUS contactors. The key difference is the coil voltage: 3RT2018-2BW42 uses a 48 VDC coil, while 3RT2016-2BB42-ZX95 uses a different coil voltage. Verify your control voltage before substituting.

Will 3RT2018-2BW42 drop into a panel specified for 3RT2016-2BB42-ZX95?

Mechanically yes — both are Size S00 with the same 45 mm width and snap-on DIN rail mounting. The wiring footprint is identical. The only difference is the coil voltage, so check that your control circuit supplies 48 VDC.

What conductor sizes does the spring terminal accept?

The spring-type terminals accept solid or stranded conductors from 0.5 to 4 mm², and also two conductors of the same range (2x 0.5 to 4 mm²).

MPN
3RT2018-2BW42