Bonding. This is an operation that was performed (and can still be used in some ports) on oil tankers to prevent electrical discharges caused by a difference of discharged.
A shore grounded cable was attached to the vessel before the cargo potential between ship and shore when the cargo of oil was being loaded or hoses are connected. The loading or discharging of oil can lead to static electricity charging and the discharge can lead to explosion if this occurs when the cargo hoses break or are disconnected because explosive oil vapours may be present during cargo handling operations.
