Power cord plugs and extension cord outlets should be designed in such a way that the cable is protected from excessive bending where it enters the accessory. This connection point is tested for durability by means of the Plug Cord Flexibility Tester. Tests are required for appliances that are movable to ensure that the bending of this connection during movement does not lead to damage of the insulating covers or the internal wiring resulting in a short circuit.
Cables are flexed through a 90° arc for 10,000 flexings. Midway through the test the cable should be rotated 90°. During the test failure is indicated by interruption of current or a short circuit. After the test, the specimen is examined for abrasion or wear, separation between the accessory and the insulation of the cord, or any strands of the conductors piercing the insulation.

Product details:Model ZLT-DW2: The ZLT  Plug Cord Flexibility Tester can test six cables or cords fitted with plugs simultaneously. This improves testing capacity. IEC 60884-1 calls for 10,000 flexings at a rate of 60 flexings per minute. Halfway through the test, the cords need to be rotated 90°. The plug sockets are designed to make this rotation easy and accurate. The ZLT Tester has individual station counters so that any failure data can be retrieved by station.
The cables are connected to a socket and the tail of the cable is connected to the tester to detect if an internal fault occurs with the cable wiring or accessory connection.
The instrument starts in a vertical orientation and then flexes the specimens 45° on either side of the vertical for a total 90° of flexing. A standard rate of 60 flexings per minute is used but a slower rate can be selected if desired.
A set of customer selected weights are included with the instrument so that the proper force can be applied to the cable during the test.