FED-STD-228A
3.1.2.3 If a bead-chain type of electrode is used, the beads shall have a diameter of 3/16 inch. The
longitudinal spacing of the chains shall be not more than ½ inch. The transverse spacing of the chains
shall be not more than 3/8 inch, except that the spacing may be ½ inch if the transverse rows of chain are
staggered.
3.1.2.4 The electrode shall be provided with a grounded metallic screen or the equivalent as a guard
against contact by personnel.
3.1.2.5 The length of electrode shall be sufficient to meet the requirements in 4.3.
3.1.3 Fault signaling device.
3.1.3.1 A fault signing device or system shall include a visible signal, a defect recording device, and/or an
automatic stop device. The arrangement shall be such that when the fault signal is given, it will be
maintained until manually reset.
4. PROCEDURE
4.1 The spark test shall be conducted as near the end of the manufacturing process as is practicable,
preferably as the wire or cable is being cut into shipping lengths.
4.2 The test voltage shall be as specified in the detail specification.
4.3 The conductor or shield of shielded and jacked cable shall be earth grounded during the spark test.
An earth-ground connection shall be made at both the pay-off and take-up reels except that, if the wire is
tested for continuity and the conductor is of one integral length, the earth-ground connection need be
made at only one point; i.e., either the take-up or pay-off reel. In any case, the conductor on a reel at
which an earth-ground connection is made shall be bonded directly to the earth ground on the
transformer in the spark tester.
4.4 The length of the electrode is not specified, but the rate of speed at which the wire travels through the
electrode shall result in any point on the wire being in contact with the electrode for not less than a total of
18 positive and negative crests of the supply voltage ( the equivalent of 9 full cycles of the supply
voltage). The maximum acceptable speed for the wire shall be determined by the following formula:
Feet per minute = 5/9 × frequency in hertz × electrode length in inches
5. RESULTS
5.1 Unless otherwise specified in the detail specification, the entire delivery of the wire or cable shall be
tested.
5.2 Whether the insulation of the entire delivery withstood the specified test voltage without failure shall
be recorded.
5.3 The test voltage shall be recorded.
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