Assuming mains neutral fault and not lightning strike.
Why just digiboxes bursting into flames , not TVs , cell phone chargers etc

http://www.sunderlandecho.com/news/S...-in.3844143.jp

http://www.thisislondon.co.uk/news/a...yhem+as+neighb
ours'+digiboxes+all+burst+into+flames+at+once+due+ to+power+surge/article.do

Mayhem as neighbours' digiboxes all burst into flames at once due to power
surge
Last updated at 07:37am on 06.03.08

A massive power surge triggered a number of TV digiboxes to burst into
flames on one street as firefighters dashed from house to house.

The set-top boxes began spitting sparks and residents living on the street
described the road as being "lit up like Blackpool Pier".

Firefighters had to go from house to house asking people to unplug their
electrical items as panicked home-owners ran into the street.


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