The Incident on 20 June 2005
19. Ampcontrol's maintenance crew for 20 June 2005 consisted of:
(a) One supervisor (David Dyson, service technician);
(b) Two electrical tradespersons (electricians Anthony Percival and Brock, the injured worker);
(c) Two trades assistants (Alfred Padgett and Peter Suszek); and
(d) One apprentice (Nathan Morris, apprentice electrician).
20. At approximately 6:30 on the morning of 20 June 2005 the Ampcontrol crew attended the offices at the DDCPP in the building near the "pizza hut" and signed on to the contractors' register. They were met by White and another employee of the defendant, Robert Wegner, DDCPP electrician.
21. White instructed Ampcontrol's crew that the job scope had changed and there was not going to be a complete electrical isolation of the 11kV switchboard in the switchroom because electricity supplies were needed for other parts of the plant. Half of the high voltage installations originally intended to be maintained were to be maintained. That was the No. 2 66/11kV transformer and half of the 11kV switchboard. Only those installations were therefore to be isolated for maintenance.
22. Dyson conducted a review of Ampcontrol's risk assessment document previously prepared by Darren Padgett for the 11kV switchboard. He did not write anything on the risk assessment document about new hazards because of half the switchboard now being live, or where the isolation points were located. Mr Dyson subsequently stated that the risk assessment of the changed job scope was verbal. The Ampcontrol work party also went through the risk assessment and discussed what hazards and cautions there were. Mr Dyson said that he identified the hazard of half the board being live when able to get onto the job and assess the situation to fully understand the control measures required and did a verbal risk assessment on the job in the switchroom in the pizza hut building.
23. Although Ampcontrol's risk assessment document required that as a control measure correct isolation procedures be followed, it was the defendant that was to carry out the isolation, not Ampcontrol. However no-one from Ampcontrol participated in the decisions as to how to go about isolating the plant to be maintained, and no one from the defendant reviewed Ampcontrol's risk assessment, or was shown the document and none of the risk controls there specified were conveyed by Ampcontrol to the defendant or discussed with it.
24. When Mr Dyson discussed the original risk assessment with the crew, he altered the written document. He changed the risk of electrocution on the written document from "high" to "critical". All the Ampcontrol crew then signed the risk assessment.
25. White and Wegner then went to perform the required high voltage isolations. Dyson was instructed by White to wait with his crew near the 11 kV switchroom while White and Wegner carried out these high voltage isolations.
26. Wegner gathered the high voltage live line test equipment and tested it in the 11kV switchroom. White and Wegner completed the isolation as identified in the defendant's standard job instruction (SJI 6282). These were identified as steps 5, 6, 11 and 12 in the SJI.
27. At about 9:30am White had completed the isolations as listed in SJI 6282 and verbally notified Dyson of such. Dyson then collected Ampcontrol's crew from the DDCPP control crib room and went to the 11 kV switchroom. White went through a single line diagram on the wall of the switchroom showing isolation points with the Ampcontrol maintenance crew. White asked the crew if they were satisfied and to attach locks and tags at No.2 Incomer. The power supply to the 11kV switchboard was from the 66kV switchyard by Incomer No. 1 and Incomer No. 2. As the maintenance work was to be conducted on that part of the switchboard which was supplied by Incomer No.2, Incomer No. 2 was isolated. At this point the switchboard was still energised as it was being supplied through No.1 Incomer and the circuit breaker known as the bus tie breaker, which was located in cubicle no 4 in the centre of the switchboard. Ampcontrol's crew attached personal locks and danger tags to No.2 Incomer.
28. Dyson noted that the circuit breaker for No.2 Incomer needed to be removed from its cubicle so that maintenance could be carried out on it. White agreed. Dyson and Percival lifted the circuit breaker from No. 2 Incomer to the floor.
29. Ampcontrol's crew then signed onto the "HV Switching and Access Permit No. 0599" which had been written out by Wegner. At the time the permit was signed, the No.2 Incomer had been isolated but the 11kV switchboard was still energised, through the No.1 incomer and the bus tie breaker which at that time remained closed and which was located in the bus tie cubicle. 29. The permit is a pre-printed form that gives permission to the receiver to work on or near high voltage cables and apparatus.
30. White then identified that additional isolations would be necessary to allow work to proceed on half of the 11 kV switchboard. Four additional isolations were hand-written on SJI 6282 by White:
a. 5721 RM Main 11 kV Switch.
b. 5741 MC 415V MCB.
c. 7781 MC 415V MCB.
d. 5717 Bus Tie.
31. Wegner decided that red and white barrier tape be erected to identify the parts of the switchboard that were to remain live even after the above additional isolations, and strung the tape on the board accordingly. This tape covered the live parts of the switchboard, including the bus tie cubicle. Mr Dyson then went and checked the barrier tape around the cubicles to make sure the barrier tape was across the bus tie cubicle door which it was and it was all the way across the back of the bus tie cubicle panel. Mr Dyson then brought Ms Brock and Mr Suszek over and explained to them that all the panels with the barrier tape around there were to be considered live and that their job would be from the right hand side of the barrier tape. Mr Dyson physically showed them and pointed it out and explained to them that at the present time, the entire 11kV switchboard was still live as Mr White and Mr Wegner were required to go around and isolate the switchboard. Mr Dyson asked Ms Brock and Mr Suszek whether they were comfortable and they both said yes. Mr Dyson then told them that he was going to the 66kV switchyard with the other crew to perform some testing and told them that if they have any problems to come and get him.
32. White and Wegner then carried out the additional isolations for the 11 kV switchboard listed above. The fourth of these isolations in relation to the bus tie breaker, was performed by it being racked out, that is, being pulled forward within the cubicle and thereby breaking the contact with the bus bars located on the inner rear wall of the cubicle. As there was no trolley to enable the bus tie breaker's total removal it was left still within its no 4 cubicle in the switchboard. This acted as a circuit breaker allowing maintenance to take place on the cubicle on the right-hand side of the bus tie cubicle. The people who were in attendance at these isolations, including the bus tie breaker isolation, were Mr White, Ms Brock and Mr Suszek. Mr Wegner also was in attendance at the bus tie breaker isolation.
33. As part of the isolation procedure, Brock and Suszek went to the bus tie breaker with White and Wegner to put danger tags on the bus tie breaker and to do this the bus tie breaker door was opened. Brock said "we removed the barrier tape and put the tags on the breaker. The breaker was racked out…withdrawn". It is unclear whether the barrier tape remained over the front of the cubicle after the bus tie breaker was racked out, or whether it was moved to one side at that time. It is clear however that it was moved to one side by the time Brock and Suszek removed the bus tie breaker wholly from the cubicle.
34. Although there was a fixture inside the cubicle at the rear enabling the locking of the shutters covering the busbars, no lock was placed there. Behind the upper shutter there were live bushings still as part of the half of the switchboard that remained energised through the No.1 Incomer. Each shutter had the word "BUSBAR" written on it.
35. Brock and Suszek attached personal danger tags to the additional isolations including to the front of the bus tie breaker. White also attached a danger tag to the bus tie breaker.
36. Wegner then identified that a circuit breaker trolley would be needed to allow servicing of the HV circuit breakers and left to obtain a trolley.
37. Around 10:00am Brock and Suszek went to the 66kV switchyard to speak with Dyson and told him that they now had their isolation and then returned to the 11 kV switchroom.
38. Brock and Suszek were clearly of the view that their job scope that day included maintenance of the bus tie breaker and White subsequently confirmed that that was his expectation as well.
39. Some time later Wegner returned to the 11 kV switchroom with the trolley. He found Brock working at the front of the switchboard and Dyson working at the rear. The job at the rear of the switchboards was to remove the covers on the back and to check the bus system in the back for heat marks and cleanout. Wegner informed Ms Brock of the presence of the trolley and asked her "if she needed anything, she declined and told [Wegner] to leave it there." Wegner left the switch room to perform other duties elsewhere at the processing plant.
40. Brock started servicing the HV circuit breakers commencing with the No. 2 Incomer circuit breaker which had been placed on the floor after removal. The maintenance activities included resistance testing, general condition inspections and cleaning of the circuit breaker and also wiping out the cubicle in which the breaker was placed and in behind the shutters at the back thereof and wiping the busbars, or bushings, inside.
41. After the trolley arrived Brock went to the cubicle at the furthest right and pulled the circuit breaker onto the trolley to service it. Before servicing the circuit breakers, Ms Brock tested for dead with Mr White. Ms Brock's live line tester kept going off, so Mr White went and got his and then Ms Brock and Mr White tested for dead together. Brock then put the circuit breaker back and moved on to the next one. From the circuit breaker test reports filled in by Brock, this appears to have been the Hunter Drift and Tunnel Conveyor circuit breaker.
42. At around 11.15 am Dyson returned to the switchroom and spoke with Brock and Suszek. Dyson said that both Brock and Suszek told him that
"everything was going good" and that they could not see any problems. Dyson received a call from the crew in the 66 kV switchyard requesting gear, so he sent Suszek to deliver the required equipment.
43. Two employees of another contractor to the defendant, were working in the 415V switchroom next door to the 11kV switchroom in which Dyson, Suszek and Brock were working. One of the other contractors came into the 11kV switchroom to tell Dyson that they were testing cables through to the 11 kV switchboard and that all persons should be kept away from the rear of the 11 kV switchboard while the testing took place. Dyson then started to set up his computer for testing the protection relays on the 11 kV switchboard. He was positioned at the front of the No. 2 Power Factor Unit cubicle.
44. When Suszek returned from the switchyard, Dyson advised him of the testing by the other contractor and asked him to assist Brock with circuit breaker maintenance until he received confirmation from the other contractor that it was all clear. At this stage Brock had arrived at the bus tie breaker with the trolley after she carried out maintenance of the cubicles on the right-hand side of the bus tie cubicle. Dyson said that he explained to Brock and Suszek that "their job would be from the right hand side of the barrier tape". Suszek helped Brock remove the bus tie breaker from the cubicle out on to the trolley. Mr Dyson said that this was against his instructions to Brock and Suszek.
45. Brock then removed the panel from the front of the bus tie breaker for servicing of the breaker switch mechanism. The panel with danger tags attached was placed on the floor near the bus tie cubicle.
46. While Brock was servicing the bus tie circuit breaker Suszek began wiping out the now empty bus tie cubicle. Mr Dyson said that the bus tie cubicle was excluded from the work scope. He said that it was part of the isolation having the barrier tape against the door. He said further that he had informed Ms Brock and Mr Suszek that everything that had barrier tape across it was not part of their job scope as this was considered live.
47. There was another call from the crew in the 66kV switchyard requesting more test equipment and Suszek again went to deliver items to that location.
48. Brock turned her attention to the bus tie cubicle to finish removing dust. She lifted the lower bus bar cover in the rear of the cubicle and wiped down the 11 kV bushings in the lower bus bar behind that cover, which were connected to the de-energised (right) side of the board. Brock said "my mind wasn't completely on the job. I lifted the shutters to clean them out. I cleaned the bottom one out and then I went to clean the top one out and that's when I got the electric shock. I knew the breaker had been tagged and I just… I knew the breaker couldn't go back in but I wasn't thinking about the busbar."
49. At about 12.15 pm Brock then lifted the upper busbar shutter and when she began to wipe the bushings behind the cover, she received an electric shock from the energised (left) side of the board.
50. Brock said that "everything sort of went black" and she experienced immense pain through her upper body and went numb from the waist up, having no feeling in her arms. She suffered burns to her right index finger and left thumb.
51. Ms Brock received initial treatment and assistance at the site from personnel of both the defendant and Ampcontrol. Mr White phoned for transport by ambulance to Muswellbrook Hospital as part of the defendant's emergency response. The ambulance officers provided initial treatment and further treatment was provided by a medical practitioner at the hospital. Brock returned to work in a limited capacity about four days later.