A commission under the Consumer Affairs Agency has found that numerous fires and other serious accidents involving home-use solar power systems have been caused by factors such as old equipment and faulty cable connections.
The Consumer Safety Investigation Commission looked at 72 of the 127 cases registered with the agency’s accident information databank between March 2008 and November 2017, except for cases including those still being investigated by the National Institute of Technology and Evaluation.
All of the cases studied by the commission involved systems with solar panels made by Japanese companies.
The commission took an in-depth look at 13 cases in which roofs and other parts of houses caught fire because of problems with the panels or connection cables.
Fires linked to solar panels occurred in products that had been in use seven years or longer. Age caused problems in electric resistance inside the equipment, resulting in abnormal flows of electricity and eventually leading to accidents, according to the commission.
In some cases of fire, cables had been connected incorrectly when the solar power systems were installed or suffered short circuits due to animals chewing them.
In seven of the 13 cases in which the damage was particularly serious, there was no fire-resistant material between the solar panels and the roof.
The commission called for accident prevention measures to be taken, such as urgent inspections by producers and switching to systems with fire-resistant material.