Inspection Detail

Inspection: 101491496 - Hinderliter Heat Treating, Inc.

Inspection Information - Office: Fort Worth Area Office

Investigation Summary

A PRESSURE VESSEL WAS BEING TREATED IN AN ELECTRIC HEAT-TREATING FURNACE. THE VESSEL WAS PLACED IN THE FURNACE, WITH A SHORT PIECE OF PIPING WITHIN 0.5 INCHES OF THE RESISTIVE HEATING ELEMENT. AS THE TEMPERATURE ROSE IN THE FURNACE, THE 480-VOLT ELEMENT EXPANDED AND CONTACTED THE PRESSURE VESSEL. SINCE IT WAS ISOLATED FROM GROUND, THE VESSEL BECAME ENERGIZED. A THERMOCOUPLE, WHICH WAS ATTACHED TO THE PRESSURE VESSEL, WAS CONNECTED TO A TEMPERATURE RECORDING INSTRUMENT. THE THERMOCOUPLE, HAVING ALSO BECOME ENERGIZED THROUGH CONTACT WITH THE PRESSURE VESSEL, CAUSED THE RECORDING INSTRUMENT TO MALFUNCTION. AN EMPLOYEE WAS CALLED IN TO TROUBLESHOOT THE RECORDER MALFUNCTION. THE THERMOCOUPLE WIRES WERE DISCONNECTED FROM THE RECORDER, AND A CHECK WAS MADE OF THE INSTRUMENT. WHEN THE EMPLOYEE PICKED UP THE EXPOSED THERMOCOUPLE WIRES SO THAT HE COULD RECONNECT THEM, HE WAS IN CONTACT WITH A GROUNDED SURFACE. THE EMPLOYEE WAS ELECTROCUTED.

Keywords: E GI III, ELECTRICAL, ELECTROCUTED, ELECTRONIC EQUIPMENT, TEST EQUIPMENT, GROUND FAULT, ELEC EQUIPMENT--MISC