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Siemens 3RT2027-1KA40 — Contactors

Siemens 3RT2027-1KA40 SIRIUS Coupling Contactor, Size S0, 45

MPN3RT2027-1KA40
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Siemens SIRIUS coupling contactor, 3RT2027-1KA40, Size S0, 45 mm width, screw-type coil terminals, 24 VDC coil, rated 10 A at 24 V.

Source DocumentedChannel stated on listing & quote
Condition PhotosReal unit photos / video on request
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Worldwide DispatchDHL/FedEx — transit quoted per order
Independent China distributor & sourcing agent· Listing updated Sep 2026

Specifications

3RT2027-1KA40 — Identification
ParameterValue
Contactor frame sizeS0
3RT2027-1KA40 — Ratings & Performance
ParameterValue
Rated operational current, AC-12, max.10 A
Rated operational current, AC-4 @ 400 V22 A
Rated value @ 400 V3 A
Rated value @ 500 V2 A
Rated value @ 690 V1 A
Rated value @ 230 V5 hp
Rated value @ 24 V10 A
Rated value @ 60 V2 A
Rated value @ 110 V1 A
Rated value @ 220 V0.3 A
3RT2027-1KA40 — Control & Coil
ParameterValue
Control supply voltage typeDC
3RT2027-1KA40 — Contacts & Poles
ParameterValue
Main poles3
Main NO contacts3
Auxiliary contact reliability1 faulty switching per 100 million (17 V, 1 mA)
3RT2027-1KA40 — Protection & Coordination
ParameterValue
Short-circuit coordination type 1, fusegG: 125A (690V,100kA), aM: 50A (690V,100kA), BS88: 125A (415V,80kA)
Short-circuit coordination type 2, fusegG: 50A (690V,100kA), aM: 25A (690V, 100kA), BS88: 50A (415V, 80kA)
Aux. switch short-circuit protection, fusegG: 10 A (500 V, 1 kA)
3RT2027-1KA40 — Connection & Mounting
ParameterValue
Main circuit connectionscrew-type terminals
Aux. / control circuit connectionscrew-type terminals
Conductor cross-section, solid1 ... 10 mm²
Conductor cross-section, solid or stranded2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)
Conductor cross-section, finely stranded w/ ferrule2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)
Mounting methodscrew and snap-on mounting onto 35 mm DIN rail according to DIN EN 60715
Side-by-side mountingYes
3RT2027-1KA40 — Durability
ParameterValue
Durability (operating cycles, typ.)10 000 000
Durability with aux. switch block (cycles, typ.)10 000 000
3RT2027-1KA40 — Environmental
ParameterValue
Operating temperature range-25 ... +60 °C
Storage temperature range-55 ... +80 °C
Installation altitude, max.2 000 m
3RT2027-1KA40 — Mechanical
ParameterValue
Width45 mm
Height85 mm
Depth107 mm

Product details

The Siemens 3RT2027-1KA40 is a SIRIUS coupling contactor in Size S0. It's built for switching loads on a control signal — think interposing between a PLC output and a motor starter or heater bank, or isolating a control circuit from a power circuit. The 45 mm width and screw-type coil terminals make it a straightforward swap into a standard DIN-rail panel.

Rated at 10 A at 24 V, 2 A at 48 V and 60 V, and 5 hp at 230 V — that's the contact rating for resistive and motor loads across common control voltages. The coil is 24 VDC, with an operating range that holds in down to about 18 V (dropout around 12 V, per the rated value of 12 V). No auxiliary switch built in — you'll need a separate block if you want a feedback contact.

That's tight enough for a crowded cabinet but leaves room for wiring. The Size S0 footprint (85 mm high, 107 mm deep) fits standard enclosure layouts.

Frequently asked questions

What are the key dimensions for panel fit?

Width 45 mm, height 85 mm, depth 107 mm. Clearances: 10 mm upwards, forwards, and downwards; 6 mm at the sides.

What wire sizes does the contactor accept?

Solid or stranded: 1 to 10 mm². For the coil terminals, 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²).

Does this contactor include an auxiliary contact?

No, it has no auxiliary switch built in. You'll need a separate auxiliary contact block if you require a feedback signal.

MPN
3RT2027-1KA40