An elevator comprising a suspension member arrangement and a device for detecting a deterioration state in the suspension member arrangement , the suspension member arrangement comprising at least one suspension member having a first and a second group of electrically conductive cords ; characterised in that the device comprising: - an alternating voltage generator arrangement (G, G 1 , G 2 ) for applying a first alternating voltage U 1 to a first end of the first group of cords of the suspension member and for applying a second alternating voltage U 2 to a first end of the second group of cords of the suspension member; wherein the alternating voltage generator arrangement (G, G 1 , G 2 ) is configured to generating the first and second alternating voltages with same waveforms and a phase difference of 180°; - at least one of (i) a first voltage measurement arrangement for determining a summed voltage U+ correlating to a sum (U 3 + U 4 ) of a third voltage (U 3 ) between a second end of the first group of cords and a common electrical potential and a fourth voltage (U 4 ) between a second end of the second group of cords and the common electrical potential; and (ii) a second voltage measurement arrangement for determining a differential voltage U_ correlating to a difference (U 3 - U 4 ) between the third voltage (U 3 ) and the fourth voltage (U 4 ); - a determination unit for determining the deterioration state based on at least one of the summed voltage and the differential voltage. - an alternating voltage generator arrangement (G, G 1 , G 2 ) for applying a first alternating voltage U 1 to a first end of the first group of cords of the suspension member and for applying a second alternating voltage U 2 to a first end of the second group of cords of the suspension member; wherein the alternating voltage generator arrangement (G, G 1 , G 2 ) is configured to generating the first and second alternating voltages with same waveforms and a phase difference of 180°; - at least one of (i) a first voltage measurement arrangement for determining a summed voltage U+ correlating to a sum (U 3 + U 4 ) of a third voltage (U 3 ) between a second end of the first group of cords and a common electrical potential and a fourth voltage (U 4 ) between a second end of the second group of cords and the common electrical potential; and (ii) a second voltage measurement arrangement for determining a differential voltage U_ correlating to a difference (U 3 - U 4 ) between the third voltage (U 3 ) and the fourth voltage (U 4 ); (i) a first voltage measurement arrangement for determining a summed voltage U+ correlating to a sum (U 3 + U 4 ) of a third voltage (U 3 ) between a second end of the first group of cords and a common electrical potential and a fourth voltage (U 4 ) between a second end of the second group of cords and the common electrical potential; and (ii) a second voltage measurement arrangement for determining a differential voltage U_ correlating to a difference (U 3 - U 4 ) between the third voltage (U 3 ) and the fourth voltage (U 4 ); - a determination unit for determining the deterioration state based on at least one of the summed voltage and the differential voltage. <EOS>