UFC 3 -520-01
June 10, 2002
9-5.3
The voltage rating of a fuse is the nominal system voltage application.
Associated with the voltage rating is the maximum design voltage, marked on the
nameplate, which is the highest system voltage for which the fuse is designed to
operate. Apply the fuse for the proper phase-to -phase circuit voltage.
9-5.4
Table 9 -1 shows the various UL fuse classes. Each UL class defines certain
required operating characteristics; however, a certain fuse classification does not mean
that its operati ng characteristics are identical to those of the same class provided by
other manufacturers. Class RK and Class L fuses are preferred over Class K and Class
H because of their greater interrupting capacity. Ensure low voltage fuses comply with
the appropriate UL standard.
Table 9-1. Low Voltage Fuse Classifications
Rating
Interrupting
UL
Typical Application--Comments
Rating
AC
Class
Amperes
(Amperes)
Volts
L
600
6016,000
200,000
Transformers, mains
J
600
1 600
200,000
Motors, mains, load centers,
panelboards--current limiting, high
interrupting capacity
RK1
250,
0.1 600
200,000
Motors, mains, load centers,
600
panelboards-- current limiting
RK5
250,
0.1 600
200,000
Transformers, motors--current
600
limiting
CC
600
0.1 30
200,000
Transfo rmer control circuit--current
limiting, high interrupting capacity
G
480
1 60
100,000
Current limiting, high interrupting
capacity
T
300,
1 1,200
200,000
Current limiting, high interrupting
600
capacity
K5
250,
1 600
50,000
Motor, branch circuit-- non current
600
limiting labeled although they might
have current limiting features
H
250,
1 600
10,000
Residential use
600
9-13
Previous Page
