Information on the most widely used ASTM standards within the materials testing industry
Model: UTOF35-T, IEC 60794-1-21 Method E7: Torsion Test
UTOF35-T Optical Fiber Cable Torsion Testing Machine is Suitable for testing the ability of optical cables to withstand mechanical twisting, by applying forward and reverse twisting forces. For qualified optical cables, the optical fibers should not break, the attenuation change of the fibers should not exceed the value specified in the detailed specifications of the cable product, the cable sheath should not crack, and the core components should not be damaged. Compliant with IEC 60794-1-E7 Torsion Test.
General introduction
UTOF35-T Optical Fiber Cable Torsion Testing Machine is Suitable for testing the ability of optical cables to withstand mechanical twisting, by applying forward and reverse twisting forces. For qualified optical cables, the optical fibers should not break, the attenuation change of the fibers should not exceed the value specified in the detailed specifications of the cable product, the cable sheath should not crack, and the core components should not be damaged. Compliant with IEC 60794-1-E7 Torsion Test.
This test method is intended to establish the ability of a fibre optic cable to withstand mechanical twisting. The primary purpose of this procedure is to measure any variation in the optical power transmittance of a fibre when the cable is subjected to torsional forces external to the cable sheath. A secondary purpose is to evaluate the possibility of physical damage that may occur as a result of such stresses.
![]() | ![]() |
| Cable torsion tester | Cable torsion testapparatus with tension applied |
Test Procedure:
Install the specimen in the test apparatus such that the test length L is as required by below Table.

Take care to insure that no initial stress is applied to the specimen. Except for the necessary twisting operation, take care not to move or disturb the specimen ends throughout the test.
Rotate the movable cable clamp as follows:
a) 180° clockwise;
b) return to the starting position;
c) 180° counter-clockwise;
d) return to the starting position.
This total four-part movement constitutes one cycle. Complete each cycle within 1 min maximum, for a total of 10 cycles.
Carry out the acceptance criteria parameters measurements. Allow the specimen to rest for a minimum period of 5 min. If necessary, the sample may be removed from the apparatus for visual examination using normal corrected vision.
The detail specification shall be reported:
a) number of cycles;
b) cycle time.
Key Features
This device uses a human-machine interface and PLC control, with a TFT true color screen to display test parameters and experimental data. It can be equipped with different weights and various clamps, meeting the torsion testing requirements for butterfly entry optical cables and other optical cables in access networks. It features stepless speed regulation, attractive design, stable performance, simple operation, and safe use.
IEC 60794-1-21 Optical fibre cables - Part 1-21: Generic specification - Basic optical cable test procedures - Mechanical tests methods
IEC 60794-1-21 Method E7: Torsion Test
EN 60794-1 Optical fibre cables - Part 1: Generic specification - Basic optical cable test procedures
GB/T 7424.21: Optical fibre cable generic specification - Part 21:Basic optical cable test procedures- Mechanical test methods
Main technical specification
| Maximum torsion length | 2000mm |
| Torsion angle | ±90°, ±180°, ±360°, ±720° selectable |
| Torsion speed | 1~8 times/minute (when speed is ±180°), freely adjustable |
| Number of twisting | 1~9999, freely adjustable |
| Weights | 5kg × 5, 2.5kg × 1 (total weight of weights 27.5kg) |
| Weight | 600kg |
| Torsion count is automatically recorded, and the test stops automatically when finished. | |
| Can start the test independently in standalone mode, or be remotely controlled by a computer; | |
Require More Customized Solutions?