For sale is an ABB REA105 Extension Unit (Catalog Code: 1MRS09041-AA / REA105-AA) designed for use within ABB’s REA arc fault protection system.

This module serves as a zone-selective extension unit for the main REA101 central unit. It is used to extend light detection via loop or radial fiber-optic sensors and provides ultra-fast, high-speed semiconductor trip outputs (IGBT) directly to circuit breakers for selective arc flash protection.

Technical Specifications

Manufacturer: ABB
Model: REA 105 / REA 105-AA
Ordering Code (MPN): 1MRS09041-AA
Type: Arc Protection Extension / Sub-module
Compatibility: Designed to operate with ABB REA 101 main relay
Inputs/Outputs:
- Sensor inputs for fiber-optic light detection (loop or radial)
- High-speed semiconductor trip outputs (HSO1, HSO2 - IGBT type)
- Communication ports (IN1 / IN2) for linking with REA101 units
Features: Built-in self-supervision system (IRF), Circuit-Breaker Failure Protection (CBFP) support

Item Condition

Used / Dismantled Unit: Removed from a working environment during switchgear decommission/upgrade.
Cosmetic Condition: May show normal signs of handling, storage, or panel installation (minor scratches/wear).

Returns & Warranty

Returns Accepted: We offer standard return windows (please check the listing shipping/returns section for details).

Need More Equipment or Have Questions?

Looking for other models or spare parts?
We have a large inventory of industrial automation, protection relays, and electrical equipment that is not yet listed on eBay. If you are looking for specific parts, complementary REA modules, or have any technical inquiries, please send us a direct message! We are happy to help.

Brand	ABB
Model	ABB REA 105

ABB REA105 (1MRS090418-AA) Arc Protection Relay Extension Unit

Shipping

Specifications

Returns Accepted