Electrical full protection circuit breaker

An electrical full protection circuit breaker for interrupting the current circuit in response to an overload current, a short circuit current, or an earth leakage or fault current, comprising the structural and functional combination of single pole circuit breaker means with an earth leakage current circuit breaker means, each having a narrow structure and the same housing contour, said leakage current circuit breaker means comprising its own contact interruption means (10, 11) and its own outwardly located terminal connection zone including a summing current transformer means accessible from outside the circuit breaker and constructed as a bushing transformer located in said terminal connection zone for operatively electrically coupling with the single pole circuit breaker means through connecting conductors leading to the circuit breaker means for detecting current, and means operatively mechanically coupling said single pole circuit breaker means and said leakage current circuit breaker means in switching engagement to form an effective double pole circuit breaker combination.