General Rules: Common misconception the size is not 6" x 6". The common metric for all three methods below is 150mm2 . If you need inches, it is 5.94 + 0, -0.06 .
It should be one continuous piece, It cannot be two; 75mm x 150mm laid side by side. The will cause problems with the results because the destructive nature of the test.
FAA definition: The standard size for specimens is 5.94 + 0, -0.06 by 5.94 + 0, -0.06 inches (150 + 0, -2 by 150 + 0, -2 mm) in lateral dimensions. Specimen thickness is as used in the relevant application up to 1.75 inches (45 mm); applications requiring thicknesses greater than 1.75 inches (45 mm) will be tested in 1.75-inch (45-mm) thicknesses.
AIRBUS definition: The standard size for specimens is (150 ± 2) mm by (150 ± 2) mm in lateral dimensions. The thickness of thepecimens shall be as that of the part installed in the aircraft, but maximal 45 mm.
BOEING definition: Specimens shall be 5.94 +0.00, -0.06 inches (150 +0, -2mm) by 5.94 +0.00, -0.06 inches(150 +0,-2mm) by the thickness of the material. The specimen holders accommodatethicknesses up to 1.75 inches (45mm). Applications requiring thicknesses greater than 1.75inches (45mm) shall be tested in 1.75 inch (45mm) thicknesses.
General Rules: This is not a required test by regulating civil aviation authorities. It is a test developed by the FAA but never implemented as a requirement. The OEM's have adopted the test as part of their internal certification process. The general rule is a 10' length for each sample, or 30' total for one mode (flaming or non-flaming). However for larger wires and cables, the guidance is wires larger than 16 AWG and all multi-conductor cables, the formula for quantity is 27/dia" = length in inches per mode.
Example, cable diameter is 0.22" then 27/0.22=123" per mode (flaming/non-flaming)
FAA definition: Insulated wire specimens, 16 AWG and smaller, will be wrapped on wire frame sample holder frame. Insert the end of a 10-foot length of insulated wire through one of the holes in the frame and complete the wrap by inserting the finishing end of the insulated wire through the unused hole and under the last turn to prevent unwinding. Specimens, 14 AWG and larger, should be cut approximately 3 inches in length and laid side by side, covering the entire opening in the front of the specimen holder.
AIRBUS definition: For electrical or non-electrical cable with an outer diameter of less than 3,3 mm and a minimal bending radius of less than 3,2 mm, one specimen should be at least 3100 mm long.For electrical or non-electrical cable with an outer diameter in the range of 3,3 to 6,4 mm or for cables with a minimum bending radius of higher or equal than 3,2 mm, one specimen should be at least 1600 mm long.
BOEING definition: Wrap a 10.0 ±0.1 foot length of AWG 20 wire