At around 10:48am, on September 20th, 2007, a cooperating company worker found 
a small fire from an electrical cable of a temporary air-conditioner located on 
the roof of the unit 1 reactor combination building at the Kashiwazaki-Kariwa 
Nuclear Power Station. The worker initiated a fire fighting action immediately 
by using a fire extinguisher, and at 10:51am, the event was reported to the local 
fire department. The fire department confirmed that the fire was extinguished at 
11:26am. (Announced on September 20th, 2007.)

We made investigations on the temporary air-conditioner in question to find out 
the cause of the fire. However, the connector unit of the power cable considered 
as the origin of fire was too heavily damaged to find out the direct cause of the 
fire.
The temporary air-conditioner in question had been rented and used as an alternative 
to the existing air-conditioner being repaired. Investigations were also made on 
the 3 other temporary air-conditioners of the same model which were rented and 
installed in the same area. As a result, it was confirmed that there was a trail 
of overheat in the connector unit of the power cable connected to one of the 3 
temporary air-conditioners, and that the area around the soldered part of the 
connector unit in question was molten. As for the 2 other air-conditioners, it 
was confirmed that there were defectively soldered parts in the connector units 
of the power cables.
From these findings, we estimated that the fire in the temporary air-conditioner 
in question was caused by overheating of the defectively soldered part in the 
connector unit of the power cable.

As measures taken against the recurrence of such a fire, we will use temporary 
connector-type power cables only after having confirmed the soundness of its 
connector unit by disassembling and checking it, and also will appropriately 
monitor the connector unit by periodically checking it during the period of use.