| Case Name |
Overhead wires were damaged by a boom of a truck-mounted crane. |
| Pictograph |
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| Date |
July 29, 2002 |
| Place |
Ogawa Town, Shimomashiki District, Kumamoto Prefecture. |
| Location |
A stockyard out of the site in a piping work of water pipe. |
| Overview |
A operator went alone to take some ductile pipes in a stockyard 200m away from the site. The overhead wires which crossed over were cut off by boom of a truck-mounted crane, when he loaded the cargo to the 4t truck-mounted crane and reversed it to come out of the stockyard. Because of this, high-voltage lines next to the overhead wires were damaged, and power cut was caused by earthing. |
| Incident |
When the operator loaded the ductile pipes to the truck-mounted crane and he came out of the stockyard, he forgot to put away the boom of the truck-mounted crane. And since in this condition he reversed and went out of the stockyard, the overhead wires were cut off. |
| Sequence |
* After the work started in the afternoon, the operator went alone to take the ductile pipes in the stockyard 200m away from the site, as instructed by the foreman.
* The operator drove into the stockyard, and he extended the boom of the truck-mounted crane, and loaded the requested ductile cast-iron pipes.
* After the loading end, the operator put away outrigger of the truck-mounted crane.(He felt sure that he put away the boom at the time.)
* The operator returned to the driver's seat, and put the car into reverse gear, and started moving backwards.
* When the truck-mounted cranes moved to 3 - 4m, he cut off the wired circuit within the overhead wires which crossed over.
* The cut wired circuit twined round the high voltage lines of an electric power company next to the wired circuit as a rebound phenomenon.
* It was the opinion of restoration of the wired circuit and power cut investigation of an electric power company that the power cut resulted in the wired circuit twinning round the high-voltage lines.
* It turned out that there was the damage in the high-voltage lines near the place where the
circuit was cut off. |
| Cause |
* The operator felt sure that he put away the boom, when he put away the outrigger.
* The work in the stockyard had been carried out many times with the induction man, but on that day the work was carried out alone.
* Because of high temperature and humidity, the operator's attention declined.
* The operator only knew that he cut off the wired circuit, but he didn't know that the high-voltage lines earthed.
* There was no high-voltage lines protection, protection above, or attention sign for the overhead wires.
* Since the stockyard was narrow, 4t truck-mounted crane couldn't rotate.
* Safety indication in the site was carried out, but safety indication and safety control in the stockyard were not carried out thoroughly.
* Consultation and request about high-voltage lines protection with an electric power company was not made at the commencement of the work.
* The attention and indication matter about the on-the-spot obstacles such as the overhead wires was specified in the crane operational procedure book. |
| Countermeasures |
* Consulting with an electric power company, protective pipe is installed in overhead wires.
* In the case that a stockyard is narrow and a truck-mounted crane bigger than 4t can't rotate in the stockyard, the induction man is stationed.
* Since material delivery vendors also come and go in a stockyard, the contact system is established, and the necessary indication is done every time.
* The safety education for subcontract partner companies and vendors of material delivery are carried out.
* The site round of sites and stockyards by the staff member is carried out. |
| Knowledge Comment |
* No one has eyes in the back of his or her head, so anyone can't see back.
* People shouldn't work alone.
* Preparing countermeasures beforehand is important when dealing with dangerous situations.
* There is a case in which people concerned don't see earthing. |
| Background |
* Since the stockyard was narrow, in the case that the crane function of the truck-mounted crane was used, it had to advance in the yard, and after end of the work, it had to reverse to the road. |
| Reason for Adding to DB |
Since the same mistake is not repeated. |
| Scenario |
| Primary Scenario
|
Insufficient Analysis or Research, Insufficient Environment Study, Poor Value Perception, Poor Safety Awareness, Misjudgment, Misperception, Usage, Operation/Use, Regular Movement, Careless Movement, Bad Event, Electrical Failure, Damage to Society, Social Systems Failure, Possible Damage, Potential Hazard
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| Number of Deaths |
0 |
| Number of Injuries |
0 |
| Physical Damage |
The power cut. |
| Field |
Civil Engineering
|
| Author |
KITAJIMA, Munekazu (TEKKEN CORPORATION)
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