Abstract: A substation of the "one-and-one-half breaker" type has three identical gastight cubicles in the form of a rectangular parallelepipeds (11, 11', 11") each containing one circuit breaker and two disconnects, and each having electricity lead-ins for connecting the disconnectors with external busbars and/or cables. The lead-ins are disposed in oblique rows through the top face of each cubicle in a front row of lead-ins (27, 27A, 27B) and in a parallel rear row of lead-ins (27', 27'A, 27'B). The two outermost cubicles (11, 11") have lead-ins, front lead-ins in one case and rear lead-ins in the other, fitted for connection to a respective incoming feeder. The middle cubicle (11') has the lead-ins of the one row individually connected by interconnections busbars (35) to the lead-ins constituting a row of the one of the adjacent cubicles that is not fitted for connection to an incoming feeder.