The presence of low voltage connectivity data (relation from MV/LV transformer with end user) provides information for critical correction management of electrical distribution cable networks. The system when used in GIS solution enables to calculate transformer load balances, faults, preventive maintenance task planning, etc., and at end and also guarantees high quality electrical supply. To handle such electric utilities needs, Ariadna Instruments has designed the new ILF12 which is a low voltage phase and feeder identifier capable to identify 3 phases and up to 12 feeders of a transformer´s output. The equipment is designed to determine the connectivity between subscribers and the different feeders and phases of an MV/LV transformer substation with high speed, ease and reliability.