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Siemens 3RU2126-4PB0 SIRIUS Thermal Overload Relay, Class 10

MPN3RU2126-4PB0

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Siemens SIRIUS 3RU2126-4PB0 thermal overload relay, S0 size, CLASS 10 trip, with integrated auxiliary signaling contact (for message "Tripped").

$45.72Ref. price · indicative, final on quote

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Siemens 3RU2126-4PB0 datasheet (PDF)

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

Specifications

3RU2126-4PB0 — Identification
Parameter	Value
Product brand name	SIRIUS
Product designation	thermal overload relay
Frame size (overload relay)	S0
Combinable contactor sizes	S0
Reference code (IEC 81346-2)	F

3RU2126-4PB0 — Protection & Trip
Parameter	Value
Overload current setting range	30 ... 36 A
Trip class	CLASS 10
Overload release type	thermal

3RU2126-4PB0 — Electrical (main circuit)
Parameter	Value
Rated operational current	36 A
Poles (main circuit)	3
Rated operating frequency	50 ... 60 Hz
Rated insulation voltage (AC, pollution degree 3)	690 V
Rated value (AC-3e), max.	690 V
Rated surge withstand voltage	6 kV
Main current circuit	screw-type terminals
Power loss at rated current (hot)	9.6 W
Per pole	3.2 W

3RU2126-4PB0 — Auxiliary contacts
Parameter	Value
Auxiliary contacts: NO	1
Auxiliary contacts: NC	1
Auxiliary contacts: CO (changeover)	0
Auxiliary switch short-circuit protection (required fuse)	fuse gG: 6 A, quick: 10 A
Switching current at 24 V	2 A
Switching current at 60 V	0.3 A
Switching current at 110 V	0.22 A
Switching current at 120 V	3 A
Switching current at 125 V	0.22 A
Switching current at 220 V	0.11 A
Switching current at 230 V	2 A
Switching current at 400 V	1 A

3RU2126-4PB0 — Connection & Mounting
Parameter	Value
Mounting / fastening method	Contactor mounting
Mounting position	any
Main-circuit connector arrangement	Top and bottom
Auxiliary/control circuit connection type	screw-type terminals
Removable aux./control terminal	No
Conductor cross-section: solid or stranded	2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)
Conductor cross-section: finely stranded with ferrule	2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)
Conductor range (AWG), main contacts	2x (16 ... 12), 2x (14 ... 8)
Conductor range (AWG), auxiliary contacts	2x (20 ... 16), 2x (18 ... 14)

3RU2126-4PB0 — Environmental
Parameter	Value
Operating temperature	-40 ... +70 °C
Storage temperature	-55 ... +80 °C
Transport temperature	-55 ... +80 °C
Relative humidity, operating	10 ... 95 %
Max. installation altitude	2 000 m

3RU2126-4PB0 — Mechanical
Parameter	Value
Width	45 mm
Height	85 mm
Depth	85 mm

Product details

It is designed to mount directly on SIRIUS contactors (fastening method: contactor mounting) and protect motor circuits up to 690 V. An integrated auxiliary switch provides a separate "Tripped" signal — useful for remote indication without an external aux block.

Mounts directly on the matching SIRIUS contactor (any mounting position). Main circuit connections use screw terminals (M4) accepting 2×(0.5…1.5 mm²) or 2×(0.75…2.5 mm²) solid or stranded. Strip length follows standard screw-terminal practice. A Pozidriv PZ2 screwdriver is specified for the terminals.

Frequently asked questions

What does the note 'for message Tripped' mean?

It means the integrated auxiliary switch is a signaling contact that changes state when the overload relay trips, providing a remote 'tripped' signal without an external auxiliary block.