Portable Light Strings Follow these precautions when using portable light strings: Inspect the wiring and fixtures before stringing the lights or before they are energized or plugged in. Make sure the outer insulation is not damaged, the plug ends are intact, and the fixtures are not cracked. The light-string must be grounded. Make certain the plug has a ground prong. Never cut one off. The quality of the ground must be tested frequently. A good ground could save your life if an electrical fault develops, especially when working in wet conditions or on metal structures. If a Ground Fault Interrupter (GFI)...