ETC 7123K1003 Main Circuit Breaker Option Kit For Echo Relay PanelThe ETC 7123K1003 is a configuration specific breaker option kit for Unison Echo Relay Panel installations. Identified in the Echo Relay Panel ordering table as ERP 100A 3P 10kA MCB, this kit supports projects that require a 120 208 V main circuit breaker assembly with a 3 pole, 100 A rating. It is suited to specification driven lighting control deployments where panel configuration accuracy matters during ordering, installation, and service planning.