Fuses? How Do They Differ?
#1
Team Owner
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Fuses? How Do They Differ?
This is not necessarily C2-related but it does have automotive relevance. In looking through the Owner's Manual for my latest old Corvette I had a peek at the fuse and breaker data. To my eye they all look very much the same: glass and cylindrical. But the descriptions differ. Here are examples:
-headlamp circuit, circuit breaker (seems straight-forward)
-backup lamps & turn signal, AGC fuse (20 amp)
-heater-A/C, 3AG fuse (25 amp)
-tail lamps, SFE fuse (20 amp)
What is the difference between AGC, 3AG, and SFE?
*Edit*-This pic shows the whole story. The year is 1974.
-headlamp circuit, circuit breaker (seems straight-forward)
-backup lamps & turn signal, AGC fuse (20 amp)
-heater-A/C, 3AG fuse (25 amp)
-tail lamps, SFE fuse (20 amp)
What is the difference between AGC, 3AG, and SFE?
*Edit*-This pic shows the whole story. The year is 1974.
Last edited by Paul L; 04-28-2008 at 09:58 AM.
#2
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C2 of Year Finalist (track prepared) 2019
This is not necessarily C2-related but it does have automotive relevance. In looking through the Owner's Manual for my latest old Corvette I had a peek at the fuse and breaker data. To my eye they all look very much the same: glass and cylindrical. But the descriptions differ. Here are examples:
-headlamp circuit, circuit breaker (seems straight-forward)
-backup lamps & turn signal, AGC fuse (20 amp)
-heater-A/C, 3AG fuse (25 amp)
-tail lamps, SFE fuse (20 amp)
What is the difference between AGC, 3AG, and SFE?
-headlamp circuit, circuit breaker (seems straight-forward)
-backup lamps & turn signal, AGC fuse (20 amp)
-heater-A/C, 3AG fuse (25 amp)
-tail lamps, SFE fuse (20 amp)
What is the difference between AGC, 3AG, and SFE?
AGC vs 3AG, I couldn't say.
Jim
#3
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AGC glass fuses are all the same length (1-1/4"), regardless of rating, from 1 amp to 30 amps. SFE (Society of Fuse Engineers) glass fuses are the same diameter as AGC fuses (1/4"), but are six different lengths depending on their amp rating (from 5/8" long for 1-amp to 1-7/16" long for 30-amp).
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Brain spasm with my posting yesterday.
The SFE fuse designation is NOT a slow acting fuse. I believe the original automotive designation for a slow acting fuse, as is needed for brake lights, was SAE.
In any event slow acting fuses are available in the Bussman brand, the MDL series:
http://host1.publiquik.com/bussmann_...?familyUid=695
Jim
The SFE fuse designation is NOT a slow acting fuse. I believe the original automotive designation for a slow acting fuse, as is needed for brake lights, was SAE.
In any event slow acting fuses are available in the Bussman brand, the MDL series:
http://host1.publiquik.com/bussmann_...?familyUid=695
Jim
#7
Melting Slicks
Don't stress over this, just use the correct amp rated fuse!
The "slo blow" refers to the time it takes to blow when the fuse is in a severe overload condition.
The "slo blow" refers to the time it takes to blow when the fuse is in a severe overload condition.
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#9
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The 3AG fuse is "fast" acting. Typical times at percent of rated current are: 4 hours at 110%, 1 hour at 135%, 5 seconds at 200% - all at 32 volts.
ACG fuses have about the same time@load ratings, but are rated at 110volts.
Which is specified should depend on several factors: whether ambient temperature of the device will effect the current draw, start up draw interaction if multiple devices are on the same fuse, and of course the preference of the designer.
Last edited by magicv8; 04-30-2008 at 11:01 AM.