A circuit breaker having internal power monitoring and data signal generating apparatus, and a system for utilizing such a circuit breaker in a facility having a plurality of tenants served by branch circuits from a plurality of distribution panels. The circuit breaker radiates signals indicative of power consumption of the branch circuit protected thereby, together with a unique address identifier tied to one tenant. Electrical billings are based on summing all signals for each tenant. Changes to branch circuits during tenancy will not disturb correct billings since individual circuit breakers are associated with that tenant using power supplied by each branch circuit. Hence changes to branch circuits may be limited to modify building space locations served by the modified branch circuit, and need not be further modified to maintain correct billing in light of the circuit changes.