2-13
Following the style designation is a number that is the current rating of the fuse (1). This could be a
whole number, a fraction, a whole number and a fraction, a decimal, or a whole number and a decimal.
Following the current rating is the voltage rating; which, in turn, is followed by the letter "V," which
stands for volts or less (250V).
NEW COMMERCIAL DESIGNATION
Figure 2-10, view B, shows the new commercial designation for fuses. It is the same as the old
commercial designation except for the style portion of the coding. In the old commercial system, the style
was a combination of letters and numbers. In the new commercial system, only letters are used. In the
example shown, 3AG in the old system becomes AGC in the new system. Since "C" is the third letter of
the alphabet, it is used instead of the "3" used in the old system. Once again, the only way to find out the
time delay rating is to look up this coding in the manufacturer’s catalog or to use a cross-reference listing.
The remainder of the new commercial designation is exactly the same as the old commercial designation.
Q16. What are the voltage, current, and time delay ratings for a fuse with the designation
Q17. What are the voltage and current ratings for a fuse designated
Q18. What is the new military designation for a fuse with the old military designation F05A20ROB?
FUSEHOLDERS
For a fuse to be useful, it must be connected to the circuit it will protect. Some fuses are "wired in"
or soldered to the wiring of circuits, but most circuits make use of FUSEHOLDERS. A fuseholder is a
device that is wired into the circuit and allows easy replacement of the fuse.
Fuseholders are made in many shapes and sizes, but most fuseholders are basically either clip-type or
post-type. Figure 2-11 shows a typical clip-type and post-type fuseholder.
