U\)This specification covers 2, 3, and 4 cadmium copper alloy stranded retractile conductor electrical cords. These cords are insulated with a natural rubber compound encased in a Buna S or Buna S and natural rubber compound jacket which is vulcanized in a helical spring coil form to produce a cord which will extend and retract freely. These cords are designed for use on communications equipment at audio frequencies, with a temperature range of -0 to 60 degrees C for continuous operation.

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MIL-DTL-13273C

4.5.7 Buna S insulation and jacket. Conformance with the physical requirements for the Buna S

insulation and jacket shall be determined by subjecting specimens removed from the completed cord to

the following tests. Unless otherwise specified herein all tests shall be conducted in an atmosphere as

specified in section 6 of FED-STD-228.

4.5.7.1 Tensile strength. Tensile strength shall be determined in accordance with FED-STD-228,

method 3021.

4.5.7.2 Elongation. Elongation shall be determined in accordance with FED-STD-228, method 3031.

The elongation after aging shall be based on the bench marks applied before aging.

4.5.7.3 Set. Set shall be determined in accordance with FED-STD-228, method 3161 except that:

a. Bench marks shall be 2 inches (50.80 mm) apart.

b. The test specimens shall be stretched so that the distance between bench

marks is 6 inches; they shall then be released within 5 seconds.

c. Set shall be determined 1 minute after the beginning of release.

4.5.8 Extended length. The finished cord shall be tested to determine compliance with 3.8.2.

4.5.9 Static load. The finished cord shall be given a static load test to determine compliance with

4.5.10 Retraction. The finished cord shall be tested to determine compliance with 3.8.3.1.

4.5.11 Stretch. The finished cord shall be tested to determine compliance with the requirements of

3.8.1. Compliance with these requirements shall be determined by measuring the resistance of the

conductors and inspection of the jacket at the start of the test, and after 60,000 cycles are completed.

4.5.12 Oxygen-bomb aging. Oxygen-bomb aging shall be performed in accordance with

FED-STD-228, method 4011, except that the aging period shall be 96 hours, as specified in section 3.

5. PACKAGING

5.1 Packaging. For acquisition purposes, the packaging requirements shall be as specified in the

contract or order (see 6.2). When actual packaging of materiel is to be performed by DoD personnel, or

in-house contractor personnel, these personnel need to contact the responsible packaging activity to

ascertain packaging requirements. Packaging requirements are maintained by the Inventory Control

Point packaging activities within the Military Service or Defense Agency, or within the military service's

system command. Packaging data retrieval is available from the managing Military Service or Defense

Agency's automated packaging files, CD-ROM products, or by contacting the responsible packaging

activity.

6. NOTES

(This section contains information of a general or explanatory nature that may be helpful, but is not

mandatory.)

6.1 Intended use. These cords are designed for use on communications equipment at audio

frequencies, with a temperature range of 0 to 60�C for continuous operation. It is designed for extension

in normal service up to five times its nominal retracted length.