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Grey rectangular IEC overload relay with screw terminals and direct contactor mount

SIEMENS

SIEMENS 3RU21261HB0 Overload Relay 5.5-8A 690V AC Trip Class 10

SKU CH-10ZA-5RCN9

Thermal overload relay with 5.5–8 A range, 690 V AC rating and trip class 10 for three-phase motor protection

  • Thermal protection for 5.5–8 A motor circuits
  • Trip Class 10 limits nuisance tripping
  • 690 V AC rating suits industrial supplies
  • Direct contactor mounting saves panel space
  • Auto and manual reset options simplify recovery

SIEMENS 3RU21261HB0 Thermal Overload Relay

The SIEMENS 3RU21261HB0 is a three-pole thermal overload relay designed for industrial motor protection. It suits maintenance engineers and panel builders who need reliable overload monitoring for three-phase circuits up to 690 V AC.

Direct Contactor Mounting with Screw Terminals

This unit mounts directly onto a compatible SIRIUS contactor in frame size S0, reducing panel space and wiring time. Screw terminals accept standard ferrules, and the built-in 1NO/1NC auxiliary contacts free up separate control-circuit components.

Trip Class 10 for Sustained Overload Response

Trip Class 10 means the relay trips within a defined time under sustained overload rather than on brief inrush. The adjustable 5.5 A to 8 A range lets you match the motor full-load current, while auto and manual reset modes give flexibility after a fault clears.

How it compares

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

Price $66.99
Typical for this category: the median of 1,098 items is $61.99.

Specifications

Product
Brand nameSIEMENS

Questions about this item

What is the maximum continuous current the 3RU21261HB0 can handle before the Trip Class 10 protection activates?

The relay trips when current exceeds the 8 A maximum setting, with Trip Class 10 timing defining the response speed under sustained overload.

How much heat does the SIEMENS overload relay generate during all-day operation at full 8 A load?

As a thermal overload device, it dissipates heat proportional to the 5.5–8 A current range; no explicit power-loss figure is published for continuous 8 A duty.

Which contactor frame must I already own to mount this relay directly?

It mounts directly onto SIRIUS Series contactors with Frame Size S0 using the integrated screw terminals.

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