The Delta XR Series Relays are low burden electro-mechanical supervision relays for application on high security tripping and auxiliary supply circuits. The Delta XR relays have been designed to provide a balance of low burden to minimize the possibility of circuit breaker maloperation while maintaining a minimum contact whetting current to avoid nuisance alarm conditions. A key feature of the design is a high visibility flag indicator that can only be reset under healthy supervision conditions. An optional green Healthy LED may also be specified. Failure of the circuit or supply being supervised will cause the main relay element to drop out, the flag to fall and the alarm contacts to change state. A wide voltage range and standard hand reset flag reduces the number of model variations. The Delta range is packaged in a size 2, 2U high case that may be flush panel, rack or rail mounted. A plug in terminal block is provided to allow panel pre-wiring.