As a firefighter I feel the need to comment here, as I have in the past, and defend firefighters.
The cause being determined as "Electrical" does not necessarily mean premise wiring. Appliances, extension cords, baseboard heaters etc. are all in the electrical category. Just because the paper states the cause as "Electrical" doesn't mean that the investigators report says that, it usually is more accurately described as to the origin and not just "Electrical". Don't take what is written in the paper as gospel.
Another issue I have with what may be written in the paper or on the news is the source of the information. Most times the reporter asks some firefighter on scene who shouldn't be (isn't qualified to) comment on origin and he states "Electrical". This is a discipline problem with in the fire department and spreads false information, because, as we all know, give the media one tid bit of info and they run with it. The only one who should ever comment on cause and origin is the fire investigator, everyone else should be giving the canned response that they beat into our brains at the academy "The cause of this fire is still under investigation and I am not able to comment at this time".
The morale of my story is, don't believe everything you read in the paper or hear on the news - firefighters aren't really as dumb as everyone thinks.