Exposed energized connections: Ungrounded terminals, junctions and bus bars must be insulated or enclosed. For DC terminals, the risk is a short circuit (think of an aluminum boat hook falling against an ungrounded terminal and a seawater strainer or engine block). In the best-case scenario, it blows a fuse or trips a circuit breaker. In the worst-case scenario, it leads to a fire. In the case of AC wiring, an exposed hot terminal is a short circuit, fire and electrocution risk. Every hot AC terminal or junction should reside within a dedicated electrical locker (behind a fastened or locked circuit-breaker panel), or within a purpose-made junction box.