3RU2116-1DB0 Siemens SIRIUS Overload relay


  • 3RU2116-1DB0
  • Overload relay for motor protection
  • 2.2-3.2 A
  • Size S00
  • CLASS 10
  • Screw connection
  • Auxiliary contacts 1 x NC/NO
  • Manual/automatic reset

Overload relay Siemens SIRIUS 3RU2116-1DB0


Mountable accessories for 3RU thermal overload relay

SIRIUS 3RU2136-4.B0 thermal overload relays

3RU21 thermal overload relays up to 100 A have been designed to provide current-dependent protection for loads with normal starting against impermissibly high temperature rises due to overload or phase failure.

An overload or a phase failure result in an increase of the motor current beyond the set rated motor current. Via heating elements, this current rise heats up the bimetal strips inside the device which then bend and as a result trigger the auxiliary contacts by means of a tripping mechanism. The auxiliary contacts then switch off the load by means of a contactor. The break time depends on the ratio between the tripping current and the current setting Ie and is stored in the form of a long-term stable tripping characteristic curve see .

The “tripped” status is signaled by means of a switch position indicator. The relay is reset manually or automatically after a recovery time has elapsed.

The 3RU2 thermal overload relays are suitable for operation with frequency converters.

The devices are manufactured in accordance with environmental guidelines and contain environmentally friendly and reusable materials. They comply with all important worldwide standards and approvals.

Use in hazardous areas

The 3RU2 overload relays are certified in accordance with both the European explosion protection directive (ATEX) and the international explosion protection standard (IECEx), see .

Article No. scheme


The Article No. scheme shows an overview of product versions for better understanding of the logic behind the article numbers.

For your orders please use the article numbers quoted in the selection and ordering data.


The most important features and benefits of the 3RU21 thermal overload relays are listed in the overview table in the “Overload Relays” node.



The 3RU21 thermal overload relays are suitable for customers from all industries who want to guarantee optimum inverse-time delayed protection of their electrical loads (e.g. motors) under normal starting conditions (CLASS 10, 10A).


The 3RU21 thermal overload relays have been designed for the protection of three-phase and single-phase AC and DC motors.

If single-phase AC or DC loads are to be protected by the 3RU21 thermal overload relays, all three bimetal strips must be heated. For this purpose, all main current paths of the relay must be connected in series.

Ambient conditions

3RU21 thermal overload relays compensate temperature in the temperature range from -40 °C to +60 °C according to IEC 60947‑4‑1. At temperatures from +60 °C to +70 °C, the upper set value of the setting range has to be reduced by a specific factor in accordance with the table below.

Use of SIRIUS protection devices in conjunction with IE3/IE4 motors


For the use of 3RU21 electronic overload relays in conjunction with highly energy-efficient IE3/IE4 motors, please observe the information on dimensioning and configuring, see .

Technical specifications


Overload relay 2.2…3.2 A Thermal For motor protection Size S00, Class 10 Contactor mounting Main circuit: Screw Auxiliary circuit: Screw Manual-Automatic-Reset


DataSheet in PDF

Weight 0.157 kg
Dimensions 49.00 × 102.00 × 84.00 mm


product brand name


product designation

thermal overload relay

product type designation


size of overload relay


size of contactor can be combined company-specific


power loss [W] for rated value of the current at AC in hot operating state

5.7 W

● per pole

1.9 W

insulation voltage with degree of pollution 3 at AC rated value

690 V

surge voltage resistance rated value

6 kV

maximum permissible voltage for safe isolation in networks with grounded star point

● between auxiliary and auxiliary circuit

440 V

● between main and auxiliary circuit

440 V

shock resistance acc. to IEC 60068-2-27

8g / 11 ms

type of protection according to ATEX directive 2014/34/EU

Ex II (2) GD

certificate of suitability according to ATEX directive 2014/34/EU

DMT 98 ATEX G 001

reference code acc. to IEC 81346-2


installation altitude at height above sea level maximum

2 000 m

ambient temperature

● during operation

-40 … +70 °C

● during storage

-55 … +80 °C

● during transport

-55 … +80 °C

temperature compensation

-40 … +60 °C

relative humidity during operation

10 … 95 %

number of poles for main current circuit


adjustable current response value current of the current-dependent overload release

2.2 … 3.2 A

operating voltage

● rated value

690 V

● at AC-3 rated value maximum

690 V

operating frequency rated value

50 … 60 Hz

operational current rated value

3.2 A

operating power at AC-3

● at 400 V rated value

1.1 kW

● at 500 V rated value

1.5 kW

● at 690 V rated value

2.2 kW

design of the auxiliary switch


number of NC contacts for auxiliary contacts


number of NO contacts for auxiliary contacts


● note

for message "Tripped"

number of CO contacts for auxiliary contacts


operational current of auxiliary contacts at AC-15

● at 120 V

3 A

● at 230 V

2 A

● at 400 V

1 A

operational current of auxiliary contacts at DC-13

● at 24 V

2 A

● at 60 V

0.3 A

● at 110 V

0.22 A

● at 125 V

0.22 A

● at 220 V

0.11 A

contact rating of auxiliary contacts according to UL

B600 / R300

trip class


design of the overload release


full-load current (FLA) for 3-phase AC motor

● at 480 V rated value

3.2 A

● at 600 V rated value

3.2 A

● for short-circuit protection of the auxiliary switch required

fuse gG: 6 A, quick: 10 A

mounting position


fastening method

Contactor mounting

product component removable terminal for auxiliary and control circuit


type of electrical connection

● for main current circuit

screw-type terminals

● for auxiliary and control circuit

screw-type terminals

arrangement of electrical connectors for main current circuit

Top and bottom

● at AWG cables for main contacts

2x (20 … 16), 2x (18 … 14), 2x 12

type of connectable conductor cross-sections

● for auxiliary contacts

— solid or stranded

2x (0.5 … 1.5 mm²), 2x (0.75 … 2.5 mm²)

— finely stranded with core end processing

2x (0.5 … 1.5 mm²), 2x (0.75 … 2.5 mm²)

● at AWG cables for auxiliary contacts

2x (20 … 16), 2x (18 … 14)

tightening torque

● for main contacts with screw-type terminals

0.8 … 1.2 N·m

● for auxiliary contacts with screw-type terminals

0.8 … 1.2 N·m

design of screwdriver shaft

Diameter 5 … 6 mm

size of the screwdriver tip

Pozidriv PZ 2

design of the thread of the connection screw

● for main contacts


● of the auxiliary and control contacts


failure rate [FIT] with low demand rate acc. to SN 31920

50 FIT

MTTF with high demand rate

2 280 y

T1 value for proof test interval or service life acc. to IEC 61508

20 y

protection class IP on the front acc. to IEC 60529


touch protection on the front acc. to IEC 60529

finger-safe, for vertical contact from the front

display version for switching status

Slide switch

Vibration and Shock

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