Abstract: An easy-to-assemble compact connection system can be connected to a mains via connection to different switchgear devices, such as a residual-current or thermomagnetic circuit breaker, switches, contact breakers, overvoltage protectors or similar devices, in order to collect or inject signals available on the mains, such as collecting current or voltage signals from the mains or collecting or injecting other signals or parameters. The compact connection system can be connected to both switchgear devices already installed in a switchboard and to new units.