On arrival at Santa Barbara Municipal Airport (SBA), Santa Barbara, California, United Airlines flight 2428 (UAL2428), operating from San Francisco International Airport (SFO), San Francisco, California, experienced multiple electrical system fault indications after landing and during taxi-in. Following the aircraft’s arrival at its gate, a ramp service agent sustained serious injuries after entering the jet blast area of an engine that remained running during ramp operations. No damage to the aircraft was reported. The flight crew reported that the flight segment from SFO to SBA was uneventful. After landing and clearing the runway, the first officer (FO), who was the pilot monitoring, started the auxiliary power unit (APU) and conducted the after-landing checklist. The captain, who was the pilot flying, taxied the airplane toward gate 2, where ramp personnel were positioned to receive the aircraft. As the airplane approached the stopping point at the gate, the Electronic Centralized Aircraft Monitoring (ECAM) system annunciated a Level 2 caution chime and light with a “ELEC APU GEN FAULT” on the Engine/Warning Display. The captain verbalized “ECAM” and instructed the FO to “Stand by” on the ECAM procedure as the captain prioritized their parking guidance. Upon reaching the designated gate stop point, the marshaller signaled the flight crew to stop the airplane, and the captain set the parking brake. The FO subsequently shut down the Number 2 (right) engine in accordance with the standard parking procedure. Immediately following the right engine shutdown, the flight crew observed multiple ECAM fault messages, including an intermittent right engine fire warning accompanied by an aural alert and illumination of associated warning lights. The indication cleared within several seconds. With the left engine still running and the aircraft beacon still on the captain instructed the FO to begin ECAM actions to try and get the APU GEN back online. The flight crew attempted to reset the APU generator; however, the fault condition persisted. The crew then requested ground power before shutting down the remaining Number 1 (left) engine. Ramp personnel informed the crew that jet bridge power could not be connected while the left engine was still operating. A portable ground power unit (GPU) was subsequently retrieved and connected to the aircraft. After verifying that external power was available, the flight crew shut down the left engine and completed the parking checklist. According to the captain, the elapsed time from parking brake set to engine shutdown was approximately 10 minutes. Once the aircraft was secured, the captain and FO coordinated with United Maintenance Control to troubleshoot the electrical system faults. During this time, the FO was informed by the ramp lead that one of the ground crew members, serving as a wing walker, had sustained a serious injury from jet blast while the left engine remained running. According to the ramp lead, the injured wing walker approached the aircraft prematurely to place chalks at the main landing gear and entered the jet blast zone without confirming that the left engine had been shut down. The ramp lead indicated that the employee was relatively new and may have misinterpreted marshalling procedures, potentially confusing the procedures with those used by other carriers operating at SBA. According to United, there were 5 ground crew members in place to bring in UAL2428. The marshaller was behind the aircraft nose stop mark, one wing walker was on the left-wing side of the airplane, the lead ramp agent and the right-wing walker was at the right-wing side of the airplane, and another support ramp agent was by the jetbridge to handle the chocks and other arrival duties. Once the aircraft came to a stop, the marshaller gave the X signal (stop), and the support agent placed the nose landing gear chocks. The support ramp agent does not need an all-clear signal to chock the nose landing gear, as this position is not exposed to engine jet blast. The marshaller then gave the hand signal to the flight crew indicating that the aircraft was chocked and lowered his hands. Standard procedure requires the left and right wing walkers—who are potentially exposed to engine jet blast—to wait for an all-clear signal from the marshaller before approaching the airplane to chock the main landing gear. The injured ramp service agent (left wing walker) indicated that he was waiting for the “safe-to-approach” signal from the marshaller but was uncertain whether he misinterpreted the signal or received it in error. He proceeded behind the left engine while carrying wheel chocks, unaware that the engine was still operating. He recalled being struck by jet blast and falling onto his left side, sustaining multiple injuries. He reported experiencing shock and was unable to feel pain immediately after impact. Nearby personnel assisted him and transported him to the on-site emergency response vehicle. The injured agent reported that he was not distracted or under time pressure and had already serviced four flights that day. The lead ramp agent stated that the ramp experienced a brief delay due to the ongoing electrical issue reported by the flight crew. During this time, the injured ramp agent appeared to misinterpret the marshaller’s gestures as the all-clear signal and began approaching the aircraft carrying two wheel chocks. The lead agent observed that the anti-collision beacon remained illuminated and that the left engine was still operating. He attempted to radio the injured agent to stop, but the agent did not appear to have heard the transmission. Moments later, the agent was struck by the exhaust blast from the operating left engine resulting in the agent being thrown to the ground. Following the accident, United issued a safety alert reminding the employees that aircraft must only be approached after marshallers give the “Safe to Approach” signal and only after confirming the nose gear is chocked, both engines are fully shut down and spooled down, the beacon light is off, and emphasizing “when in doubt, wait.”