A circuit breaker panel includes a number of circuit breaker modules each having a number of connectors, a plurality of circuit breakers and a circuit structure supporting the circuit breakers and electrically interconnecting the circuit breakers with the number of connectors. The panel also includes a monitoring module having a connector and a monitoring circuit to monitor at least one line voltage and, for each of the circuit breakers, at least one load voltage. The panel further includes a frame having a first connector for the monitoring module connector, a number of second connectors for the circuit breaker module connectors, and a number of third connectors for outputs from the circuit breaker modules. Conductors are connected to the connectors. Any of the monitoring module and the number of circuit breaker modules can be installed into or removed from the frame without change to the conductors.