Inspection Detail

Inspection: 310091426 - Cupertino Electric, Inc

Inspection Information - Office: Foster City District Office

Investigation Summary

On October 28, 2006, Employee #1, a supervisor and project manager for Cupertino Electric, was part of a crew performing a scheduled wire pulling operation to prepare for a full factory startup testing phase procedure. In the "battery room" of the facility, a factory splice was missing between two 2-volt batteries in a 500-volt bank of batteries. Employee #1 attempted to install a jumper (a piece of cable with lugs on each end) between the two batteries. When the jumper made contact with the battery, the circuit was completed, resulting in an arc flash and blast. Employee #1 suffered second- and third-degree burns to his hands and arms and first- and second-degree burns to his chest, upper abdomen, neck, and face. Subsequent investigation determined that (1) the cables from battery strings 3A and 3B were not landed properly on the line side of the breakers; (2) battery string 3B was connected so that the polarity was the opposite of the field installation drawing; (3) because of the above two issues, there was a potential direct current voltage between the two points being connected; (4) a missing factory splice plate during the battery installation caused a gap; (5) no set of written instructions--referred to as a method of procedure--was created, written, or provided to the personnel working on the energized equipment and parts necessary for the factory startup test, a violation of T8CCR 2320.2(a)(2); and (6) Employee #1 was working alone in the battery distribution room. Since he was a supervisor, he was considered under Title #8 California Code of Regulations as the "authorized" person to work on energized systems. Referencing items #1, #2, #3, and #4, this substantiated a violation of Section 3328(f). Employee #1 attempted to modify the improper installation of the battery system using a jumper that was not a factory-authorized part. He and supervisory personnel later stated that he had not performed a potential test of the electrical current on the equipment and had not treated the system as energized. In addition, Employee #1 did not wear suitable personal protective equipment for working on energized equipment. A test on the energized equipment would have warned him of the potential current; approved insulated gloves and a flame-retardant top, would have protected him from an arc flash.

Keywords: BATTERY, BURN, ELEC PROTECT EQUIP, ELECTRIC ARC, WORK RULES, CONSTRUCTION, ELECTRICAL WORK, ELEC CIRC PART--MISC, HAND