Abstract: A circuit breaker detects a loose electrical connection condition of a power circuit. The circuit breaker includes first and second lugs, first and second acoustic couplers acoustically coupled to the power circuit, separable contacts electrically connected in series between the first and second lugs, and an operating mechanism adapted to open and close the contacts. An acoustic generator is coupled to the second acoustic coupler and generates a first acoustic signal to the power circuit from the second acoustic coupler. An acoustic sensor is coupled to the first acoustic coupler and has a second acoustic signal which is operatively associated with the loose electrical connection condition. The acoustic sensor outputs a sensed acoustic signal. A circuit cooperates with the acoustic generator to generate the first acoustic signal, input the sensed acoustic signal, and detect the loose electrical connection condition therefrom.

Abstract: An electronic apparatus, such as a meter, includes an enclosure having a first housing portion with an opening and a second front plate portion. Meter circuitry is mounted within the enclosure. The second front plate portion mates with the first housing portion within the opening and forms an interface joint. The housing and front plate portions are at least substantially co-planar proximate the interface joint and include a plurality of mating crenellations. These mating crenellation, such as serrations, reduce electromagnetic interference radiation to or from the enclosure when the housing and front plate portions are mated together.