Method 107 evaluates the thermal and mechanical resistance of a wire bundle by measuring how long the bundle can resist penetration from a heated soldering iron. Ten 12-inch insulated wire specimens of the same size are bundled together and secured with string ties every 3 inches from either end.
The barrel of the soldering iron is laid perpendicularly across the bundle without touching any string tie. The time for the iron to make contact with any conductor in the bundle is measured. The test may be terminated if no penetration occurs within 5 minutes.
Testing is performed at three temperatures: 398°C (750°F), 343°C (650°F), and 288°C (550°F). Three locations are tested for each temperature, with each contact point at least 0.5 inch from any previous contact point.