Michael;

That's right...lighters were not fused...your experience is what's called learning a lesson the hard way...I'm glad the damage was limited and is repairable...I call it excellent advise to add an in-line fuse if one is going to use the ancient cigarette lighter for modern conveniences...I have no need to use it for its intended purpose (and on all of my cars, its position has been replaced with an Emergency Blinker) but having a place for on-board power is sure convenient...better yet, replace it with a new 12V power outlet...those crunchy sounds the old lighters make when you push in the element never inspired me with much confidence anyway...and I too have seen them fail, although not quite as spectacularly.

I would say a 3A fuse would be adequate for most modern electronic loads like a GPS or phone or computer, but check the load rating to be sure.

Cheers from Connecticut!