The same is true if your ground lead on a lighting instrument becomes disconnected. This can happen several ways:
- A two wire connector (an old style two-pin 2P&G stage plug or a two-bladed Edison plug) is installed on a three-wire cable
- A ground-lift adapter is installed on the end of a normally grounded NEMA 5-15P connector
- The wire breaks internally
- The wire gets yanked-out of the connector body
- The wire gets yanked out of the lighting instrument body
In any case, you are in a situation that would let the fault current of an internal problem in a lighting instrument look for another path back to the source, and that path may be you!