Aviation analyst, Scott Hamilton, is predicting a 4 to 6 month delay in delivering the 787 to customers. He is saying that the cause of the fire is being narrowed down and that it could be an instance of FOD (foreign object damage) that started the fire in the P100 power panel. The fires was not related to any testing activity
Still the panel and the electrical system would need to be redesigned but Boeing has a good handle on the scope of the work to be done. Additionally, Boeing is working with the FAA in order to resume flight testing while using a work around the panel issue and at the same time undertake the redesign of the the panel.
Scott Hamilton: Our 787 forecast: 4 - 6 month delay
FOD does seem (at this point) logical for the following reason: during the two plus years that the 787 first flight was delayed, Boeing and Hamilton Sundstrand had thoroughly tested the electrical system including the P100 panel in the Boeing systems lab in Seattle. There was no known occurrence of fire during those tests. As such because of the delays, many of the 787 systems have been thoroughly tested and are considered mature systems. Any issues that were uncovered during that time would have been corrected by now.