A deterioration state of load bearing capacity in an elevator suspension member having a plurality of electrically conductive cords is detected by: providing a multi-phase alternating current circuitry including electrically conductive legs; applying at least one phase of a multi-phase alternating current to at least one of the cords electrically connected to one of the legs; applying at least another phase of the current to at least another cord and at least one resistor electrically connected to at least another leg; measuring an electric indicator current being at least one of a net sum of all phases of the current and an electric bypass current through a neutral wire being connected in parallel to the circuitry, wherein a peak current in each phase is shifted by a phase angle with respect to a peak current in another phase; and determining the deterioration state based on the measured indicator electric current.