With the mild winter we've had in 2017, I took my car over to Buffalo at the end of February to get gas and groceries.  While in the Wegman's parking lot, upon turning off the engine and turning my key to the accessory position to listen to the radio after my wife closed her door, everything went dead.  I've had similar issues in the past with the bad battery terminal connection so I checked my connections and all were tight.  I then spun the glass battery fuse in its connectors and the lights came back on.  After starting the car, I got as far as the stop sign in the parking lot where it happened again.  This time, I loosened and re-tightened my battery terminals and the lights came back on again.  After driving back along the Thruway, I got as far as the Duty Free Americas by US Customs at the Peace Bridge before the car once again died.  Nothing I did previously worked this time so I admitted defeat and called CAA for a tow.  While waiting, I discovered that my seemingly good 30 amp glass fuse was defective (bad solder between the fuse and end cap?) since I could get the lights to come back on if I touched the fuse's connectors together.  Unfortunately, my spare 30 amp fuses were not with me and I did not have any way to bypass the fuse for the trip home.

Because my old AGC fuse holder had frayed wires and because blade fuses are more common now, I decided to replace this AGC fuse with a regular ATC/ATO blade-style fuse.  'ATC' fuse elements are completely closed to atmosphere inside of their plastic housings.  'ATO' fuse elements are open to atmosphere and can potentially fail from corrosion.  ATC fuses would likely present less risk of sparks and shocks.  I have not found a definitive guide for ATO vs ATC usage and the ATC/ATO description is used interchangeably (and misleadingly IMHO).  Presumably, ATO fuses are cheaper than ATC fuses because ATO fuses seem to be more prevalent than ATC fuses.  Also, ATO fuses appear to be the standard product offering from Littelfuse while ATC appears to be a Bussman standard product.

 

Blade Fuse

 

I tried a 20 amp ATC fuse (salvaged from a wreck during an earlier quest for parts) but, after a long cold-weather cranking session, it blew shortly after my car started while I was warming up the engine.  I replaced it with a 30 amp ATO fuse and I've had no fuse issues so far.  The photo below shows the difference between a blown 20A ATC fuse (left) with a new 30A ATO fuse (right).

 

ATC vs ATO Fuses