A system and method of locking housings that have two different stages, one being generally used for transportation after an initial production stage, and the other being intended for final use of the product, preferably used on electric compressor inverters. One example presents a system for locking housings that have a base (1), a cover (2) and internal elements (4) arranged in an internal portion of the base (1), the cover (2) being locked to the base (1) by at least one fastening element (3), the fastening element (3) having first reversible locking stage (a) and second irreversible locking stage (b), the locking system being configured so that the reversible locking stage (a) will enable the opening of the housing for access to the internal elements (4), and the irreversible locking stage (b) will effect tamper-proof closure of the housing.