Abstract: At 11:25 a.m. on August 3, 2019, Employee #1 and Employee #2 were working together while one was attempting to attach a grounding conductor to the SF6 123-1-6 switch in the Cherry/ Sheldon street vault without adequate verification of the correct circuit or usage of appropriate protective equipment and safeguarding techniques. Employees #1 and #2 were wearing hardhats, safety glasses, arc flash clothing and non-insulative work gloves, but were not wearing adequate face, arm, or body protection for arc flash hazards. They did not use hot stick type live line tools for the connections. One employee under observation of the other tested the circuit, but did not verify the test instrument against another known live source prior to, or after, the testing of the switch. An arc occurred when a grounding cable was applied to a live circuit energized at 7200 volts and 200 amps on the SF6 123-1-6 Switch in the Cherry/ Sheldon street vault. Employees #1 and #2 were exposed to the flash. As stated, the employees did not use live line tools, or adequately verify the accuracy of the Hastings phasing stick used as a test instrument prior to grounding. Elements of arc flash protection, including face shields, insulative gloves, and sleeves, were omitted also. The employees were working in close proximity to the circuit receiving the ground, and in hand contact with grounding connections being applied. The employees applied multiple grounds prior to the fault. Employee #1 was hospitalized when the arc occurred resulting in second degree burns to his hands and facial area. Employee #2 was also burned to the second degree and treated as an outpatient.