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Siemens 3RU21161JB0 thermal overload relay, grey plastic housing, screw terminals

SIEMENS

SIEMENS 3RU21161JB0 Overload Relay 7-10A 690V AC

SKU CH-XTAH-WGSQV

Thermal overload relay protects three-phase motors from 7 A to 10 A at 690 V AC with automatic or manual reset

  • Thermal overload protection for motors up to 10 A
  • 690 V AC rating suits industrial three-phase supplies
  • Trip Class 10 gives standard response to sustained overcurrent
  • Auto and manual reset options restore operation quickly
  • Direct contactor mounting with screw terminals simplifies panel wiring

Application & fit

The SIEMENS 3RU21161JB0 is a thermal overload relay rated for three-phase circuits up to 690V AC. It protects motors drawing between 7 A and 10 A and mounts directly onto a compatible SIRIUS contactor in frame size S00. The unit includes the required thermal elements and offers both automatic and manual reset modes for flexible restart policies.

Sustained-load behaviour

Trip Class 10 means the relay opens within a defined time band when current exceeds the set point continuously, limiting temperature rise during prolonged overloads. The 1NO/1NC auxiliary contacts change state at the same moment, giving a clean signal to control circuits without contact bounce. Screw terminals maintain clamping force through thermal cycling, so the protection threshold stays consistent over long service intervals.

Build & daily use

Direct-to-contactor mounting eliminates separate DIN-rail hardware and keeps the starter footprint compact inside the panel. Three-pole construction with screw terminals allows straightforward wiring with standard hand tools, and the IEC relay style matches common European motor-control layouts. The relay is supplied new and carries no NEMA size designation, so installers should verify dimensional compatibility with the chosen contactor before assembly.

How it compares

Measured against everything we stock in Contactors, Relays & Motor Starters, at today’s prices. Recalculated every night.

Price $53.99
Cheaper than about 56% of the 1,098 comparable items (median $61.99).

Specifications

Product
Brand nameSIEMENS

Questions about this item

How much heat does the 3RU21161JB0 generate when running at 10 A all day?

The relay uses thermal overload protection rated for a maximum current setting of 10 A and a 690 V AC maximum voltage. Trip Class 10 defines its heating-time response under sustained load.

What contactor must I already own to mount this overload relay directly?

It mounts directly to a compatible SIRIUS series contactor with frame size S00 using screw terminals for the main circuit connections.

Will the 7-10 A setting range cover the motor I already run on an older starter?

The adjustable range spans 7 A minimum to 10 A maximum with three included thermal units. It provides 1NO/1NC auxiliary contacts for control circuits on three-phase loads.

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