The power source which led to the incident was protected by a GFCI breaker in the breaker box. However, the GFCI did not activate in time to prevent damage to the meter probe. Research into GFCI activation revealed some important information. A GFCI does not limit the magnitude of the fault current. Instead, it limits only the duration of the fault.
Voltage surges from lightning, utility switching, and other sources take their toll on GFCIs.
Make sure a GFCI circuit is properly protecting prior to its use. Where the potential exists to create a dead-short, consider alternatives to eletrical sources that are potentially wired in with equipment being removed. The RCT was performing a continuous radiological survey of inaccessible areas as electrical components were disassembled and removed from a distillation unit. An electrician had verified no electrical power with an electrical probe prior to removing a cover plate with attached switch from a switch box. This occurred before the electrician verified there were no live wires in the box.