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Circuit Protection
Electrical distribution systems are often quite complicated. They
cannot be absolutely fail-safe. Circuits are subject to destructive
overcurrents. Harsh environments, general deterioration, acci-
dental damage, damage from natural causes, excessive expan-
sion, and/or overloading of the electrical distribution system are
factors which contribute to the occurrence of such overcurrents.
Reliable protective devices prevent or minimize costly damage to
transformers, conductors, motors, and the other many compo-
nents and loads that make up the complete distribution system.
Reliable circuit protection is essential to avoid the severe mone-
tary losses which can result from power blackouts and prolonged
downtime of facilities. It is the need for reliable protection, safety,
and freedom from fire hazards that has made the fuse a widely
used protective device.
Overcurrents
An overcurrent is either an overload current or a short-circuit cur-rent. The overload current is an excessive current relative to nor-
mal operating current, but one which is confined to the normal
conductive paths provided by the conductors and other compo-
nents and loads of the distribution system. As the name implies,
a short-circuit current is one which flows outside the normal con-
ducting paths.
Overloads
Overloads are most often between one and six times the normal
current level. Usually, they are caused by harmless temporary
surge currents that occur when motors are started-up or trans-
formers are energized. Such overload currents, or transients, are
normal occurrences. Since they are of brief duration, any tem-perature rise is trivial and has no harmful effect on the circuit
components. (It is important that protective devices do not react
to them.)
Continuous overloads can result from defective motors (such as
worn motor bearings), overloaded equipment, or too many loads
on one circuit. Such sustained overloads are destructive and
must be cut off by protective devices before they damage the
distribution system or system loads. However, since they are of
relatively low magnitude compared to short-circuit currents,
removal of the overload current within minutes will generally pre-
vent equipment damage. A sustained overload current results in
overheating of conductors and other components and will cause
deterioration of insulation, which may eventually result in severedamage and short-circuits if not interrupted.
Short-Circuits
Whereas overload currents occur at rather modest levels, the
short-circuit or fault current can be many hundred times larger
than the normal operating current. A high level fault may be
50,000 amperes (or larger). If not cut off within a matter of a few
thousandths of a second, damage and destruction can become
rampant—there can be severe insulation damage, melting of
conductors, vaporization of metal, ionization of gases, arcing,
and fires. Simultaneously, high level short-circuit currents can
develop huge magnetic-field stresses. The magnetic forces
between bus bars and other conductors can be many hundreds
of pounds per linear foot; even heavy bracing may not be ade-
quate to keep them from being warped or distorted beyond
repair.
Fuses
The fuse is a reliable overcurrent protective device. A “fusible” link
or links encapsulated in a tube and connected to contact termi-
nals comprise the fundamental elements of the basic fuse.
Electrical resistance of the link is so low that it simply acts as a
conductor. However, when destructive currents occur, the link
very quickly melts and opens the circuit to protect conductors
and other circuit components and loads. Fuse characteristics are
stable. Fuses do not require periodic maintenance or testing.Fuses have three unique performance characteristics:
1. Modern fuses have an extremely “high interrupting
rating”—can withstand very high fault currents without
rupturing.
2. Properly applied, fuses prevent “blackouts.” Only the
fuse nearest a fault opens without upstream fuses
(feeders or mains) being affected—fuses thus provide
“selective coordination.” (These terms are precisely
defined in subsequent pages.)
3. Fuses provide optimum component protection by
keeping fault currents to a low value…They are said to
be “current limiting.”
Voltage Rating
The voltage rating of a fuse must be at least equal to or greater
than the circuit voltage. It can be higher but never lower. For
instance, a 600 volt fuse can be used in a 208 volt circuit.
The voltage rating of a fuse is a function of its capability to
open a circuit under an overcurrent condition. Specifically,
the voltage rating determines the ability of the fuse to suppress
the internal arcing that occurs after a fuse link melts and an arc
is produced. If a fuse is used with a voltage rating lower than the
circuit voltage, arc suppression will be impaired and, under some
fault current conditions, the fuse may not clear the overcurrent
safely. Special consideration is necessary for semiconductor fuseand medium voltage fuse applications, where a fuse of a certain
voltage rating is used on a lower voltage circuit.
Ampere Rating
Every fuse has a specific ampere rating. In selecting the ampere
rating of a fuse, consideration must be given to the type of load
and code requirements. The ampere rating of a fuse normally
should not exceed the current carrying capacity of the circuit. For
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instance, if a conductor is rated to carry 20 amperes, a 20
ampere fuse is the largest that should be used. However, there
are some specific circumstances in which the ampere rating is
permitted to be greater than the current carrying capacity of the
circuit. A typical example is the motor circuit; dual-element fuses
generally are permitted to be sized up to 175% and non-time-
delay fuses up to 300% of the motor full-load amperes. As a rule,
the ampere rating of a fuse and switch combination should be
selected at 125% of the continuous load current (this usually
corresponds to the circuit capacity, which is also selected at
125% of the load current). There are exceptions, such as when
the fuse-switch combination is approved for continuous opera-
tion at 100% of its rating.
Interrupting Rating
A protective device must be able to withstand the destructive
energy of short-circuit currents. If a fault current exceeds the
capability of the protective device, the device may actually rup-ture, causing additional damage. Thus, it is important when
applying a fuse or circuit breaker to use one which can sustain
the largest potential short-circuit currents. The rating which
defines the capacity of a protective device to maintain its integ-
rity when reacting to fault currents is termed its “interrupting
rating”. The interrupting rating of most branch-circuit, molded
case, circuit breakers typically used in residential service entrance
panels is 10,000 amperes. (Please note that a molded case
circuit breaker’s interrupting capacity will typically be lower than
its interrupting rating.) Larger, more expensive circuit breakers
may have interrupting ratings of 14,000 amperes or higher. In
contrast, most modern, current-limiting fuses have an interrupt-
ing rating of 200,000 or 300,000 amperes and are commonly
used to protect the lower rated circuit breakers. The National
Electrical Code, Section 110-9, requires equipment intended to
break current at fault levels to have an interrupting rating sufficient
for the current that must be interrupted.
Selective Coordination – Prevention of Blackouts
The coordination of protective devices prevents system power
outages or blackouts caused by overcurrent conditions. When
only the protective device nearest a faulted circuit opens and
larger upstream fuses remain closed, the protective devices are
“selectively” coordinated (they discriminate). The word “selective”
is used to denote total coordination…isolation of a faulted circuit
by the opening of only the localized protective device.
This diagram shows the minimum ratios of ampere ratings of LOW-PEAK YELLOW fuses that are required to provide “selective coordination”(discrimination) of upstream and downstream fuses.
Unlike electro-mechanical inertial devices (circuit breakers), it is a
simple matter to selectively coordinate fuses of modern design.
By maintaining a minimum ratio of fuse-ampere ratings between
an upstream and downstream fuse, selective coordination is
assured.
Current Limitation – Component Protection
A non-current-limiting protective device, by permitting a short-circuit current to build up to its full value, can let an immense amount ofdestructive short-circuit heat energy through before opening the circuit.
A current-limiting fuse has such a high speed of response that it cuts off ashort-circuit long before it can build up to its full peak value.
If a protective device cuts off a short-circuit current in less than
one-quarter cycle, before it reaches its total available (and highly
destructive) value, the device is a “current-limiting” device. Most
modern fuses are current-limiting. They restrict fault currents to
such low values that a high degree of protection is given to circuit
components against even very high short-circuit currents. They
permit breakers with lower interrupting ratings to be used. They
can reduce bracing of bus structures. They minimize the need of
other components to have high short-circuit current “withstand”
ratings. If not limited, short-circuit currents can reach levels of
30,000 or 40,000 amperes or higher in the first half cycle (.008
seconds, 60 hz) after the start of a short-circuit. The heat that
can be produced in circuit components by the immense energy
of short-circuit currents can cause severe insulation damage or
even explosion. At the same time, huge magnetic forces
developed between conductors can crack insulators and distort
and destroy bracing structures. Thus, it is important that
a protective device limit fault currents before they reach their
full potential level.
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KRP-C1200SP
2:1 (or more)
LPS-RK 600SP
LPS-RK 200SP
2:1 (or more)
Normalload current
Initiation ofshort-circuitcurrent
Circuit breaker tripsand opens short-circuitin about 1 cycle
Areas within waveformloops represent destructiveenergy impressed uponcircuit components
Fuse opens and clearsshort-circuit in lessthan cycle
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Operating Principles of Bussmann® Fuses
The principles of operation of the modern, current-limiting Buss
fuses are covered in the following paragraphs.
Non-Time-Delay Fuses The basic component of a fuse is the link. Depending upon the
ampere rating of the fuse, the single-element fuse may have one
or more links. They are electrically connected to the end blades (or
ferrules) (see Figure 1) and enclosed in a tube or cartridge sur-
rounded by an arc quenching filler material. BUSS® LIMITRON®
and T-TRON® fuses are both single-element fuses.
Under normal operation, when the fuse is operating at or near its
ampere rating, it simply functions as a conductor. However, as
illustrated in Figure 2, if an overload current occurs and persists for
more than a short interval of time, the temperature of the link even-
tually reaches a level which causes a restricted segment of the link
to melt. As a result, a gap is formed and an electric arc estab-
lished. However, as the arc causes the link metal to burn back, the
gap becomes progressively larger. Electrical resistance of the arc
eventually reaches such a high level that the arc cannot be sus-
tained and is extinguished. The fuse will have then completely cut
off all current flow in the circuit. Suppression or quenching of the
arc is accelerated by the filler material. (See Figure 3.)
Single-element fuses of present day design have a very high
speed of response to overcurrents. They provide excellent short-
circuit component protection. However, temporary, harmless
overloads or surge currents may cause nuisance openings unless
these fuses are oversized. They are best used, therefore, in cir-
cuits not subject to heavy transient surge currents and the tem-
porary over-load of circuits with inductive loads such as motors,transformers, solenoids, etc. Because single-element, fast-acting
fuses such as LIMITRON and T-TRON fuses have a high speed of
response to short-circuit currents, they are particularly suited for
the protection of circuit breakers with low interrupting ratings.
Whereas an overload current normally falls between one and
six times normal current, short-circuit currents are quite high.
The fuse may be subjected to short-circuit currents of 30,000
or 40,000 amperes or higher. Response of current limiting fuses
to such currents is extremely fast. The restricted sections of the
fuse link will simultaneously melt (within a matter of two or three-
thousandths of a second in the event of a high-level fault current).
The high total resistance of the multiple arcs, together with thequenching effects of the filler particles, results in rapid arc sup-
pression and clearing of the circuit. (Refer to Figures 4 & 5) Short-
circuit current is cut off in less than a half-cycle, long before the
short-circuit current can reach its full value (fuse operating in its
current limiting range).
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Figure 2. Under sustained overload, a section of the link melts and an
arc is established.
Figure 3. The “open” single-element fuse after opening a circuit
overload.
Figure 4. When subjected to a short-circuit current, several
sections of the fuse link melt almost instantly.
Figure 5. The “open” single-element fuse after opening a short circuit.
Figure 1. Cutaway view of typical single-element fuse.
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Dual-Element, Time-Delay Fuses as Manufactured
by Bussmann
Unlike single-element fuses, the dual-element, time-delay fuse
can be applied in circuits subject to temporary motor overloads
and surge currents to provide both high performance short-
circuit and overload protection. Oversizing in order to prevent
nuisance openings is not necessary. The dual-element, time-
delay fuse contains two distinctly separate types of elements
(Figure 6). Electrically, the two elements are series connected.
The fuse links similar to those used in the non-time-delay fuse
perform the short-circuit protection function; the overload ele-
ment provides protection against low-level overcurrents or over-
loads and will hold an overload which is five times greater than
the ampere rating of the fuse for a minimum time of 10 seconds.
As shown in Figure 6, the overload section consists of a copper
heat absorber and a spring operated trigger assembly. The heat
absorber bar is permanently connected to the heat absorberextension (left end of illustration) and to the short-circuit link on
the opposite end of the fuse by the “S”-shaped connector of the
trigger assembly. The connector electrically joins the short-circuit
link to the heat absorber in the overload section of the fuse.
These elements are joined by a “calibrated” fusing alloy. As
depicted in Figure 7, an overload current causes heating of the
short-circuit link connected to the trigger assembly. Transfer of
heat from the short-circuit link to the heat absorbing bar in the
mid-section of the fuse begins to raise the temperature of the
heat absorber. If the overload is sustained, the temperature of the
heat absorber eventually reaches a level which permits the trig-
ger spring to “fracture” the calibrated fusing alloy and pull the
connector free of the short-circuit link and the heat absorber. As
a result, the short-circuit link is electrically disconnected from the
heat absorber, the conducting path through the fuse is opened,
and overload current is interrupted (See Figure 8.). A critical
aspect of the fusing alloy is that it retains its original characteris-
tic after repeated temporary overloads without degradation.
When subjected to a short circuit current, the restricted sections
of the short-circuit link will simultaneously melt (within a matter of
two or three-thousandths of a second in the event of a high-level
fault current). The high total resistance of the multiple arcs,
together with the quenching effects of the filler particles, results in
rapid arc suppression and clearing of the circuit. (Refer to Figures
9 & 10.)BUSS dual-element fuses, typically LOW-PEAK YELLOW™ and
FUSETRON® fuses, utilize the spring-loaded design in the over-
load element.
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Trigger Assembly
Spring
Overload
Element
Short-CircuitElement
Heat Absorber
Short-CircuitLink
Calibrated Fusing Alloy and “S” Connector
Figure 7. Under sustained overload conditions, the trigger spring fracturesthe calibrated fusing alloy and releases the “connector”.
Figure 8. The “open” dual-element fuse after opening under an overloadcondition.
Figure 10. The “open” dual-element fuse after opening under a short-circuit condition.
Figure 9. Like the single element fuse, a short-circuit current causes the
restricted portions of the short-circuit elements to melt. Arcing to burnback the resulting gaps occurs until the arcs are suppressed by the arc
quenching material and the increased arc resistance.
Figure 6. The true dual-element fuse has distinct and separate overload
and short-circuit elements.
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Fuse Time-Current Curves
When a low level overcurrent occurs, a long interval of time will
be required for a fuse to open (melt) and clear the fault. On the
other hand, if the overcurrent is large, the fuse will open very
quickly. The opening time is a function of the magnitude of the
level of overcurrent. Overcurrent levels and the corresponding
intervals of opening times are logarithmically plotted in graph
form as shown to the right. Levels of overcurrent are scaled on
the horizontal axis; time intervals on the vertical axis. The curve is
thus called a “time-current” curve.
This particular plot reflects the characteristics of a 200 ampere,
250 volt, LOW-PEAK YELLOW dual-element fuse. Note that at
the 1,000 ampere overload level, the time interval which is
required for the fuse to open is 10 seconds. Yet, at approximate-
ly the 2,200 ampere overcurrent level, the opening (melt) time of
a fuse is only 0.01 seconds. It is apparent that the time intervals
become shorter as the overcurrent levels become larger. Thisrelationship is termed an inverse time-to-current characteristic.
Time-current curves are published or are available on most com-
monly used fuses showing “minimum melt,” “average melt”
and/or “total clear” characteristics. Although upstream and
downstream fuses are easily coordinated by adhering to simple
ampere ratios, these time-current curves permit close or critical
analysis of coordination.
Better Motor Protection in Elevated Ambients
The derating of dual-element fuses based on increased ambient
temperatures closely parallels the derating curve of motors in ele-
vated ambient. This unique feature allows for optimum protection
of motors, even in high temperatures.
Affect of ambient temperature on operating characteristics of FUSETRONand LOW-PEAK YELLOW Dual-Element Fuses.
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400
300
200
10080
60
40
30
20
108
6
4
3
2
1.8
.6
.4
.3
.2
.1.08
.06
.04
.03
.02
.01
1 0
0
2 0
0
3 0
0
4 0
0
6 0
0
8 0
0
1 , 0 0
0
2 , 0 0
0
3 , 0 0
0
4 , 0 0
0
6 , 0 0
0
8 , 0 0
0
1 0 , 0 0
0
T I M E I N S E C O N D S
CURRENT IN AMPERES
LOW-PEAK YELLOWLPN-RK200 SP (RK1)
150
140
130
120
110
100
90
80
70
60
50
40
30
AMBIENT
P E R C E N T O F R A T I N G O R
O P E N I N G T I M E
Affect on CarryingCapacity Rating
Affect onOpening Time
–76°F( –60°C)
–40°F( –40°C)
–4°F( –20°C)
–32°F(0°C)
68°F(20°C)
104°F(40°C)
140°F(60°C)
176°F(80°C)
212°F(100°C)
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In the above illustration, a grooved ring in one ferrule provides the
rejection feature of the Class R fuse in contrast to the lower
interrupting rating, non-rejection type.
Branch-Circuit Listed Fuses
Branch-circuit listed fuses are designed to prevent the installationof fuses that cannot provide a comparable level of protection to
equipment.
The characteristics of Branch-circuit fuses are:
1. They must have a minimum interrupting rating of 10,000
amps.
2. They must have a minimum voltage rating of 125 volts.
3. They must be size rejecting such that a fuse of a lower
voltage rating cannot be installed in the circuit.
4. They must be size rejecting such that a fuse with a current
rating higher than the fuseholder rating cannot be installed.
Better Protection Against Motor Single Phasing
When secondary single-phasing occurs, the current in the remain-
ing phases increases to approximately 200% rated full load
current. (Theoretically 173%, but change in efficiency and power
factor make it about 200%.) When primary single-phasing
occurs, unbalanced voltages occur on the motor circuit causing
currents to rise to 115%, and 230% of normal running currents
in delta-wye systems.
Dual-element fuses sized for motor running overload protection
will help to protect motors against the possible damages of
single-phasing.
Classes of Fuses
Safety is the industry mandate. However, proper selection, overall
functional performance and reliability of a product are factors
which are not within the basic scope of listing agency activities.
In order to develop its safety test procedures, listing agencies
develop basic performance and physical specifications or stan-
dards for a product. In the case of fuses, these standards have
culminated in the establishment of distinct classes of low-voltage
(600 volts or less) fuses; classes RK1, RK5, G, L, T, J, H and CC
being the more important.
The fact that a particular type of fuse has, for instance, a classifi-
cation of RK1, does not signify that it has the identical function or
performance characteristics as other RK1 fuses. In fact, the LIM-
ITRON® non-time-delay fuse and the LOW-PEAK YELLOW™
dual-element, time-delay fuse are both classified as RK1.
Substantial differences in these two RK1 fuses usually requires
considerable difference in sizing. Dimensional specifications of
each class of fuse does serve as a uniform standard.Class R Fuses
Class R (“R” for rejection) fuses are high performance, ⁄Ω¡º to 600
ampere units, 250 volt and 600 volt, having a high degree of cur-
rent limitation and a short-circuit interrupting rating of up to
300,000 amperes (rms symmetrical). BUSS Class R's include
Classes RK1 LOW-PEAK YELLOW™ and LIMITRON® fuses, and
RK5 FUSETRON® fuses. They have replaced BUSS K1 LOW-
PEAK and LIMITRON fuses and K5 FUSETRON fuses. These
fuses are identical, with the exception of a modification in the
mounting configuration called a “rejection feature”. This feature
permits Class R fuses to be mounted in rejection type fuseclips.
“R” type fuseclips prevent older type Class H, ONE-TIME and
RENEWABLE fuses from being installed. The use of Class R fuse-
holders is thus an important safeguard. The application of Class R
fuses in such equipment as disconnect switches permits the
equipment to have a high interrupting rating. NEC Articles 110-9
and 230-65 require that protective devices have adequate capac-
ity to interrupt short-circuit currents. Article 240-60(b) requires
fuseholders for current-limiting fuses to reject non-current-limiting
type fuses.
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Bussmann®
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Fuse Diagnostic Chart
E l e c t r i c
H e a t
( N . E . C . 4 2 4 )
E l e c t r i c S p a c e H e a t i n g
E l e c t r i c B o i l e r s w i t h
R e s i s t a n c e T y p e I m m e r s i o n
H e a t i n g E l e m
e n t s i n a n A S M E
R a t e d a n d S t a m p e d V e s s e l .
I n d o o r
O u t d o o r
B a l l a s t s
O n l o a d s i d
e o f
m o t o r r u n n
i n g
o v e r c u r r e n t d e v i c e
C a p a c i t o r s
( N . E . C . 4 6 0 )
P r o t e c t e d b y
T i m e - D
e l a y
F u s e s
P r o t e c t e d b y
N o n - T i m e D e l a y
F u s e s
1 5 0 % t o
1 7 5 %
o f f u l l l o a d c u r r e n t
2 5 0 % t o
3 0 0 %
o f f u l l l o a d c u r r e n t
0 - 2 5 0 V L P N - R K_
S P ,
F R N - R
2 5 1 - 6 0 0 V L P S - R K_
S P ,
F R S - R
0 - 6 0 0 V F N Q - R ,
L P J_
S P ,
L P - C
C
0 - 2 5 0 V K T N - R ,
N O N
0 - 3 0 0 V J J N
2 5 1 - 6 0 0 V K T S - R ,
N O S
0 - 6 0 0 V J K S ,
K T K - R
3 0 1 - 6 0 0 V J J S
P r o t e c t i o n r e c o m m e n d e d
a s s h o w n b e l o w ,
b u t n o t
r e q u i r e d
M e r c u r y ,
S o d i u m ,
e t c .
A l l O t h e r
( M e r c u r y ,
S o d i u m ,
e t c . )
F l u o r e s c e n t
C o n s u l t f i x t u r e m a n u f a c t u r e r f o r s i z e a n d t y p e .
C o n s u l t f i x t u r e m a n u f a c t u r e r f o r s i z e a n d t y p e .
C o n s u l t f i x t u r e m a n u f a c t u r e r f o r s i z e a n d t y p e .
S i z e a t 1 2 5 % o
r n e x t s i z e l a r g e r b u t i n n o c a s e l a r g e r t h a n 1 5 0 a m p e r e s f o r e a c h s u b d i v i d e d
l o a d .
S i z e a t 1 2 5 % o
r n e x t s i z e l a r g e r b u t i n n o c a s e l a r g e r t h a n 6 0 a m p e r e s f o r e a c h s u b d i v i d e d l o
a d .
0 - 2 5 0 V L P N - R K_
S P ,
F R N - R ,
N O N
0 - 3 0 0 V J J N
0 - 4 8 0 V S C
2 5 1 - 6 0 0 V L P S - R K_
S P ,
F R S - R ,
N O S
3 0 1 - 6 0 0 V J J S
0 - 6 0 0 V L P J_
S P ,
L P - C
C , F N
Q - R ,
J K S ,
K T K - R
F u s e
G L R
G M F
G R F
B A F
B A N
K T K
F N M
F N Q
F N W
B A F
B A N
K T K
F N M
F N Q
F N W
H o l d e r
H L R
H P F
H P S
H E B
H E X
H P C - D
F u s e
G L Q
G M Q
K T K - R
F N Q - R
L P - C
C
K T Q
B B S
K T K - R
F N Q - R
L P - C
C
H o l d e r
H L Q
H P S - R R
H P F - R R
H P S - L
H P F - L
H E Y
F u s e
S C - 0 - 1 5
S C 2 0
S C 2 5 - 3 0
H o l d e r
H P F - E E
H P S - E E
H P F - J J
H P S - J J
H P F - F F
H P S - F F
B a s e d o n
1 9 9 6 N . E . C . ®
F u s e
F u s e
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Bussmann®
200
KRP-C, Class L Fuses
Time-Current & Current Limitation Curves
300
100
10
1
.1
.01
1 , 0 0 0
1 0 , 0 0 0
1 0 0 , 0 0 0
2 0 0 , 0 0 0
CURRENT IN AMPERES
T I M E I N
S E C O N D S
8 0 0 A
1 2 0 0
A
1 6 0 0
A
2 0 0 0
A
2 5 0 0
A
3 0 0 0
A
4 0 0 0
A
5 0 0 0
A
6 0 0 0
A
AMPERE
RATING400,000
10,000
1,000
1 0 ,
0 0 0
2 0 0 ,
0 0 0
I N S T A N T A N E O U S P E
A K L E T - T H R U
C U R R E N T I N A M P S
1 0 0 ,
0 0 0
100,000
A M P E R E
R A T I N G
6,0005,0004,0003,0002,5002,0001,6001,200
800
601
A
B
1 ,
0 0 0
KRP-C Time-Current Characteristic Curves—
Average Melt
KRP-C Current Limitation Curves
PROSPECTIVE SHORT-CIRCUIT CURRENTSYMMETRICAL RMS AMPERES
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201
LPN-RK (250V) Class RK1 Fuses
LPN-RK_SP (250V)
300
100
10
1
.1
.01
2 0
1 0 0
1 , 0
0 0
1 0
, 0 0 0
RMS SYMMETRICAL CURRENT IN AMPERES
T I M E I N
S E C O N D S
2 0 A
6 0 A
1 0 0 A
2 0 0 A
3 0 A
4 0 0 A
6 0 0 A
1 5 A AMPERE
RATING
LPN-RK_SP (250V)
1 / 1 0
2 / 1 0
1 5 / 1 0 0
3 / 1 0
4 / 1 0
6 / 1 0
1 / 2
8 / 1 0
1
1 - 1 / 4
1 - 6 / 1 0
2
2 - 1 / 2
3 - 2 / 1 0 4
5
6 - 1 / 4
8
1 0
1 2
AMPERERATING
300
10
1
.1
.01
T I M E I N
S E C O N D S
. 1 1 1 0
1 0 0
1 , 0
0 0
CURRENT IN AMPERES
Time-Current Characteristic Curves— Average Melt Time-Current Characteristic Curves— Average Melt
Time-Current & Current Limitation Curves
Current Limitation Curves
A
B
600
400
200
100
A M P E R E
R A T I N G
400,000
100,000
10,000
1,000
1 , 0
0 0
1 0 , 0
0 0
1 0 0 , 0
0 0
2 0 0 , 0
0 0
RMS SYMMETRICAL CURRENTS IN AMPERES
A–B=ASYMMETRICAL AVAILABLE PEAK (2.3 X SYMM RMS AMPS)
I N S T A N T A N E O U S P E A K
L E T - T
H R U
C U R R E N T I N A M P S
60
30
LPN-RK_SP (250V)
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202
Time-Current & Current Limitation Curves
LPS-RK (600V) Class RK1 Fuses
2 0 A
6 0 A
1 0 0
A
2 0 0
A
3 0 A
4 0 0
A
AMPERERATING 6 0 0
A
LPS-RK(600V)
3 0
1 0 0
1 , 0
0 0
1 0 , 0
0 0
2 0 , 0
0 0
300
100
10
1
.1
.01
CURRENT IN AMPERES
T I M E I N
S E C O N D S
. 1 . 2
. 1 5
. 3 . 4 . 6
. 5
. 8 1
1 . 2
5
1 . 6 2
2 . 5
3 . 2 4 5
6 . 2
5
8 1 0
1 2 AMPERE RATING
300
100
10
1
.1
.01 . 1 1
1 0
1 0 0
1
, 0 0 0
T I M E I N
S E
C O N D S
RMS SYMMETRICAL CURRENT IN AMPERES
Time-Current Characteristic Curves— Average Melt Time-Current Characteristic Curves— Average Melt
60
30
A
B
600
400
200
A M P E R E
R A T I N G
400,000
100,000
10,000
1,000
1 , 0
0 0
1 0 , 0
0 0
1 0 0 , 0
0 0
2 0 0 , 0
0 0
I N S T A N T A N E O U S P E A K L
E T - T H R U
C U R R E N T I N A M P S
100
Current Limitation Curves
LPS-RK(600V)
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Bussmann®
203
FRN-R (250V) Class RK5 Fuses
Time-Current & Current Limitation Curves
2 0
1 0 0
1 , 0
0 0
1 0
, 0 0 0
2 0
, 0 0 0
10
1
.1
.01
T I M E I N
S E C O N D S
CURRENT IN AMPERES
FRN-R(250V)
6 0 A
1 0 0 A
2 0 0 A
3 0 A
4 0 0 A
AMPERERATING 6
0 0 A
1 5 A
300
100FRN-R (250V)
1 / 1 0
2 / 1 0
1 5 / 1 0 0
3 / 1 0
4 / 1 0
6 / 1 0
1 / 2
8 / 1 0
1
1 - 1
/ 4
1 - 6
/ 1 0
2
2 - 1
/ 2
3 - 2
/ 1 0 4
5
6 - 1
/ 4
8
1 0
1 2
AMPERERATING
300
100
10
1
.1
.01
T I M E I N
S E C O N
D S
. 1 1 1 0
1 0 0
1 , 0
0 0
CURRENT IN AMPERES
Time-Current Characteristic Curves— Average Melt Time-Current Characteristic Curves— Average Melt
Current Limitation Curves
I N S T A N T A N E O U S P E A K L E
T - T H R U C U R R E N T A M P E R E S
PROSPECTIVE SHORT CIRCUIT CURRENTSYMMETRICAL RMS AMPERES
400,000
100,000
10,000
1,000
1 , 0
0 0
1 0 , 0
0 0
1 0 0 , 0
0 0
2 0 0 , 0
0 0
60
600
100
A M P E R E
R A T I N G
400
200
B
A
30
FRN-R (250V)
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Bussmann®
204
FRS-R (600V) Class RK5 Fuses
Time-Current & Current Limitation Curves
CURRENT IN AMPERES
2 0
1 0 0
1 , 0
0 0
1 0 , 0
0 0
3 0 , 0
0 0
300
100
10
1
.1
.01
T I M E I N
S E C O N D S
6 0 A
1 0 0 A
2 0 0 A
3 0 A
4 0 0 A
AMPERERATING 6
0 0 A
1 5 A
FRS-R600V
1 / 1 0
2 / 1 0
1 5 / 1 0 0
3 / 1 0
4 / 1 0
6 / 1 0
1 / 2
8 / 1 0
1
1 - 1
/ 4
1 - 6
/ 1 0 2
2 - 1
/ 2 3 - 2
/ 1 0
4 5
6 - 1
/ 4
8
1 0
1 2 AMPERE
RATING
FRS-R(600V)
300
100
10
1
.1
T I M E I N
S E C O
N D S
.01 . 1 1
1 0
1 0 0
1
, 0 0 0
CURRENT IN AMPERES
Time-Current Characteristic Curves— Average Melt Time-Current Characteristic Curves— Average Melt
Current Limitation Curves
600
100
A M P E R E
R A T I N G
400
200
30
60
I N S T A N T A N E O U S P E A K
L E T T H R U
C U R R E N T A M P E R E S
PROSPECTIVE SHORT CIRCUIT CURRENTSYMMETRICAL RMS AMPERES
B
A
400,000
100,000
10,000
1,000
1 , 0
0 0
1 0
, 0 0 0
1 0 0
, 0 0 0
2 0 0
, 0 0 0
FRS-R (600V)
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Bussmann®
205
KTN-R (250V) Class RK1 Fuses
Time-Current & Current Limitation Curves
RMS SYMMETRICAL CURRENT IN AMPERES
T I M E I N
S E C O N D S
300
100
10
1
.1
.01
4 0
1 0 0
1 , 0
0 0
1 0
, 0 0 0
3 0 A
6 0 A
1 0 0
A
2 0 0
A
4 0 0
A
6 0 0
A
AMPERERATING
600
100
60
A M P E R E
R A T I N G
30
400
200
I N S T A N T A N E O U S
P E A K L E T - T
H R U
C U R R E N T I N A M P S
400,000
100,000
10,000
1,000
1 , 0
0 0
1 0
, 0 0 0
1 0 0
, 0 0 0
2 0 0
, 0 0 0
RMS SYMMETRICAL CURRENTS IN AMPERESA–B=ASYMMETRICAL AVAILABLE PEAK (2.3 X SYMM RMS AMPS)
A
B
Time-Current Characteristic Curves— Average Melt Current Limitation Curves
KTN-R(250V)
KTN-R(250V)
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Bussmann®
206
KTS-R (600V) Class RK1 Fuses
Time-Current & Current Limitation Curves
RMS SYMMETRICAL CURRENT IN AMPERES
T I M E I N
S E C O N D S
300
100
10
1
.1
.01
4 0
1 0 0
1 , 0
0 0
1 0 , 0
0 0
3 0 A
6 0 A
1 0 0
A
2 0 0
A
4 0 0
A
6 0 0
A
AMPERERATING
600
100
60
A M P E R E
R A T I N G
30
400
200
2 0 0 , 0
0 0
1 0 0 , 0
0 0
1 0 , 0
0 0
1 , 0
0 0
1,000
I N S T A N T A N E
O U S P E A K L E T - T H R U
C U R R E N T I N A M P S400,000
100,000
10,000
RMS SYMMETRICAL CURRENTS IN AMPERESA–B=ASYMMETRICAL AVAILABLE PEAK (2.3 X SYMM RMS AMPS)
B
A
Time-Current Characteristic Curves— Average Melt Current Limitation Curves
KTS-R(600V)
KTS-R(600V)
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Bussmann®
207
LPJ (600V), Class J Fuses
Time-Current & Current Limitation Curves
AMPERERATING 1 A
3 A
5 A
1 0 A
1 5 A
2 0 A
3 0 A
4 0 A
5 0 A
6 0 A
300
100
10
1
.1
.01
T I M E I N
S E C O N D S
1 0
, 0 0 0
1 , 0
0 0
1 0 0
1 0 1
RMS SYMMETRICAL CURRENT IN AMPERES
1 0 0
A
1 2 5
A
2 0 0
A
2 2 5
A
4 0 0
A
6 0 0
A
I N S T A N T A N E O U S P E A K L E T - T H R U
C U R R E N T I N A M P S100,000
10,000
1,000
100
B
A
PROSPECTIVE SHORT-CIRCUIT CURRENTSYMMETRICAL RMS AMPS
1 0 0
1 , 0
0 0
1 0 , 0
0 0
1 0 0 , 0
0 0
2 0 0 , 0
0 0
600A400A
200A
100A60A50A40A30A20A15A
A M P E R E
R A T I N G
Time-Current Characteristic Curves—
Average Melt
Current Limitation Curves
LPJLPJ
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Bussmann®
208
JJN & JJS, Class T Fuses
Time-Current & Current Limitation Curves
Time-Current Characteristic Curves— Average Melt Time-Current Characteristic Curves— Average Melt
Current Limitation Curves Current Limitation Curves
600
400200
100
60
3015
A M P E R E
R A T I N G
8001200
I N S T A N T A N E O U S P E A K L E T - T H R U
C U R R E N T I N A M P S
RMS SYMMETRICAL CURRENTS IN AMPERESA-B = ASYMMETRICAL AVAILABLE PEAK (2.3 x SYMM RMS AMPS)
100,000
10,000
1,000
200
1 0 0
1 , 0
0 0
1 0
, 0 0 0
1 0 0
, 0 0 0
2 0 0
, 0 0 0
400,000B
A
600
400
200
10060
30
A M P E R E
R A T I N G
8001200
I N S T A N T A N E O U S P E A K L E T - T H R U
C U R R E N T I N A M P S
100,000
10,000
1,000
200
1 0 0
1 , 0
0 0
1 0
, 0 0 0
1 0 0
, 0 0 0
2 0 0
, 0 0 0
400,000B
A
RMS SYMMETRICAL CURRENTS IN AMPERESA–B=ASYMMETRICAL AVAILABLE PEAK (2.3 X SYMM RMS AMPS)
RMS SYMMETRICAL CURRENT IN AMPERES
T I M E I N
S E C O N D S
2 0
1 0 0
1 , 0
0 0
1 0
, 0 0 0
300
100
10
1
.1
.01
6 0 A
1 0 0 A
2 0 0 A
3 0 A
4 0 0 A AMPERE
RATING 6 0 0 A
1 5 A
JJN
1 A
3 A
5 A
1 0 A
3 0 A
1 5 A
6 0 A
2 0 0 A
4 0 0 A
5 0 0 A
1 0 0 A
8 0 0 A
AMPERERATING
1 0
, 0 0 0
1 , 0
0 0
1 0 0
1 0 1
300
100
10
1
.1
.01
CURRENT IN AMPERES
T I M E I N
S E C O N D S
(300V)
JJS(600V)
JJS(600V)
JJN(300V)
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Bussmann®
209
LP-CC & FNQ-R Class CC Fuses
Time-Current & Current Limitation Curves
200
100
10
T I M E I N S E C O N D S
1
.1
.01
⁄ Ω ™ fl Ω ¡ º ° Ω ¡ º 1 1 ⁄ Ω ¢
3 3 ⁄ Ω ™
4 4 ⁄ Ω ™
6 8 1 0 1 2 1 5 2 0 2 5 3 0
AMPERE
RATING
. 4 1 1 0 1 0 0
1 0 0 0
CURRENT IN AMPERES
.
4 1
1
0
1 0
0
2 0
0
RMS SYMMETRICAL CURRENT IN AMPERES
100
10
1
.1
.01
T I M E I N
S E C O N D S
1 / 2
1 3 5 7 - 1
/ 2
AMPERERATING
Time-Current Characteristic Curves— Average Melt Time-Current Characteristic Curves— Average Melt
LP-CC FNQ-R
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Bussmann®
210
KTK-R, Class CC Fuses
Time-Current & Current Limitation Curves
RMS SYMMETRICAL CURRENT IN AMPERES
T I M E I N
S E C O N D S
1 0
1 0 0
4 0 0 1
1 0
A
2 0
A
3 A
AMPERERATING 2 A 1 A 5 A 8 A 1 5
A
3 0
A
300
100
10
1
.1
.01
Time-Current Characteristic Curves— Average Melt
KTK-R
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Ampere
The measurement of intensity of rate of flow of
electrons in an electric circuit. An ampere is
the amount of current that will flow through a
resistance of one ohm under a pressure of onevolt.
Ampere Rating
The current-carrying capacity of a fuse. When
a fuse is subjected to a current above its
ampere rating, it will open the circuit after a
predetermined period of time.
Ampere Squared Seconds, l2t
The measure of heat energy developed within
a circuit during the fuse’s clearing. It can be
expressed as “melting l2t”, “arcing l2t” or the
sum of them as “Clearing l2t”. “l” stands for
effective let-through current (RMS), which is
squared, and “t” stands for time of opening, in
seconds.
Arcing Time
The amount of time from the instant the fuselink has melted until the overcurrent is inter-
rupted, or cleared.
Breaking Capacity
(See Interrupting Rating)
Cartridge Fuse
A fuse consisting of a current responsive ele-
ment inside a fuse tube with terminals on both
ends.
Class CC Fuses
600V, 200,000 ampere interrupting rating,
branch circuit fuses with overall dimensions of
⁄‹Ω£™∑ ≈ 1⁄Ω™∑ . Their design incorporates a rejec-
tion feature that allows them to be inserted
into rejection fuse holders and fuse blocks
that reject all lower voltage, lower interruptingrating ⁄‹Ω£™∑ ≈ 1⁄Ω™∑ fuses. They are available
from ⁄Ω¡º amp through 30 amps.
Class G Fuses
480V, 100,000 ampere interrupting rating
branch circuit fuses that are size rejecting to
eliminate overfusing. The fuse diameter is
⁄‹Ω£™∑ while the length varies from 1fiΩ¡§∑ to 2⁄Ω¢∑ .
These are available in ratings from 1 amp
through 60 amps.
Class H Fuses
250V and 600V, 10,000 ampere interrupting
rating branch circuit fuses that may be renew-
able or non-renewable. These are available in
ampere ratings of 1 amp through 600 amps.
Class J Fuses
These fuses are rated to interrupt a minimumof 200,000 amperes AC. They are labelled
as “Current-Limiting”, are rated for 600 volts
AC, and are not interchangeable with other
classes.
Class K Fuses
These are fuses listed as K-1, K-5, or K-9
fuses. Each subclass has designated I2t and lpmaximums. These are dimensionally the same
as Class H fuses, and they can have interrupt-ing ratings of 50,000, 100,000, or 200,000
amps. These fuses are current-limiting.
However, they are not marked “current-limit-
ing” on their label since they do not have a
rejection feature.
Class L Fuses
These fuses are rated for 601 through 6000
amperes, and are rated to interrupt a minimum
of 200,000 amperes AC. They are labelled
“Current-Limiting” and are rated for 600 volts
AC. They are intended to be bolted into their
mountings and are not normally used in clips.
Some Class L fuses have designed in time-delay
features for all purpose use.
Class R Fuses
These are high performance fuses rated ⁄Ω¡º-600 amps in 250 volt and 600 volt ratings. All
are marked “Current Limiting” on their label
and all have a minimum of 200,000 amp inter-
rupting rating. They have identical outline
dimensions with the Class H fuses but have a
rejection feature which prevents the user from
mounting a fuse of lesser capabilities (lower
interrupting capacity) when used with special
Class R Clips. Class R fuses will fit into either
rejection or non-rejection clips.
Class T Fuses
An industry class of fuses in 300 volt and 600
volt ratings from 1 amp through 1200 amps.
They are physically very small and can be
applied where space is at a premium. They are
fast acting and time-lag fuses, with an inter-rupting rating of 200,000 amps RMS.
Classes of Fuses
The industry has developed basic physical
specifications and electrical performance
requirements for fuses with voltage ratings of
600 volts or less. These are known as stan-
dards. If a type of fuse meets the requirements
of a standard, it can fall into that class. Typical
classes are K, RK1, RK5, G, L, H, T, CC, and J.
Clearing Time
The total time between the beginning of the
overcurrent and the final opening of the circuit
at rated voltage by an overcurrent protective
device. Clearing time is the total of the melt-
ing time and the arcing time.
Current Limitation
A fuse operation relating to short circuits only.
When a fuse operates in its current-limiting
range, it will clear a short circuit in less than ⁄Ω™
cycle. Also, it will limit the instantaneous peak
let-through current to a value substantially
less than that obtainable in the same circuit if
that fuse were replaced with a solid conduc-
tor of equal impedance.
Dual Element Fuse
Fuse with a special design that utilizes two
individual elements in series inside the fuse
tube. One element, the spring actuated trig-
ger assembly, operates on overloads up to5-6 times the fuse current rating. The other
element, the short circuit section, operates on
short circuits up to their interrupting rating.
Electrical Load
That part of the electrical system which actu-
ally uses the energy or does the work
required.
Fast Acting Fuse
A fuse which opens on overload and short
circuits very quickly. This type of fuse is not
designed to withstand temporary overload
currents associated with some electrical
loads.
Fuse
An overcurrent protective device with a fusible
link that operates and opens the circuit on anovercurrent condition.
High Speed Fuses
Fuses with no intentional time-delay in the
overload range and designed to open as
quickly as possible in the short-circuit range.
These fuses are often used to protect solid-
state devices.
Inductive Load
An electrical load which pulls a large amount
of current—an inrush current—when first
energized. After a few cycles or seconds the
current “settles down” to the full-load running
current.
Interrupting Capacity
See Interrupting RatingInterrupting Rating
(Breaking Capacity)
The rating which defines a fuse’s ability to
s afely interrupt and clear short circuits. This
rating is much greater than the ampere rating
of a fuse. The NEC® defines Interrupting
Rating as “The highest current at rated volt-
age that an overcurrent protective device is
intended to interrupt under standard test
conditions.”
Melting Time
The amount of time required to melt the fuse
link during a specified overcurrent. (See
Arcing Time and Clearing Time.)
“NEC” Dimensions
These are dimensions once referenced in theNational Electrical Code. They are common to
Class H and K fuses and provide inter-
changeability between manufacturers for
fuses and fusible equipment of given ampere
and voltage ratings.
Ohm
The unit of measure for electric resistance. An
ohm is the amount of resistance that will allow
one ampere to flow under a pressure of one
volt.
Bussmann®
211
Glossary of Terms
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Threshold Current
The symmetrical RMS available current at the
threshold of the current-limiting range, where
the fuse becomes current-limiting when test-
ed to the industry standard. This value can beread off of a peak let-through chart where the
fuse curve intersects the A-B line. A threshold
ratio is the relationship of the threshold cur-
rent to the fuse’s continuous current rating.
Time-Delay Fuse
A fuse with a built-in delay that allows tempo-
rary and harmless inrush currents to pass
without opening, but is so designed to open
on sustained overloads and short circuits.
Voltage Rating
The maximum open circuit voltage in which a
fuse can be used, yet safely interrupt an over-
current. Exceeding the voltage rating of a fuse
impairs its ability to clear an overload or short
circuit safely.
Withstand Rating The maximum current that an unprotected
electrical component can sustain for a speci-
fied period of time without the occurrence of
extensive damage.
R.M.S. Current
The R.M.S. (root-mean-square) value of any
periodic current is equal to the value of the
direct current which, flowing through a resis-
tance, produces the same heating effect inthe resistance as the periodic current does.
Semiconductor Fuses
Fuses used to protect solid-state devices.
See “High Speed Fuses”.
Short Circuit
Can be classified as an overcurrent which
exceeds the normal full load current of a cir-
cuit by a factor many times (tens, hundreds or
thousands greater). Also characteristic of this
type of overcurrent is that it leaves the normal
current carrying path of the circuit—it takes a
“short cut” around the load and back to the
source.
Short-Circuit Rating
The maximum short-circuit current an electri-
cal component can sustain without the occur-rence of excessive damage when protected
with an overcurrent protective device.
Short-Circuit Withstand Rating
Same definition as short-circuit rating.
Single Phasing
That condition which occurs when one phase
of a three phase system opens, either in a low
voltage (secondary) or high voltage (primary)
distribution system. Primary or secondary sin-
gle phasing can be caused by any number of
events. This condition results in unbalanced
currents in polyphase motors and unless pro-
tective measures are taken, causes overheat-
ing and failure.
Ohm’s Law
The relationship between voltage, current,
and resistance, expressed by the equation E
= IR, where E is the voltage in volts, I is the
current in amperes, and R is the resistance inohms.
One Time Fuses
Generic term used to describe a Class H
nonrenewable cartridge fuse, with a single
element.
Overcurrent
A condition which exists on an electrical
circuit when the normal load current is
exceeded. Overcurrents take on two separate
characteristics—overloads and short circuits.
Overload
Can be classified as an overcurrent which
exceeds the normal full load current of a circuit.
Also characteristic of this type of overcurrent is
that it does not leave the normal current car-
rying path of the circuit—that is, it flows fromthe source, through the conductors, through
the load, back through the conductors, to the
source again.
Peak Let-Through Current, lp
The instantaneous value of peak current let-
through by a current-limiting fuse, when it
operates in its current-limiting range.
Renewable Fuse (600V & below)
A fuse in which the element, typically a zinc
link, may be replaced after the fuse has
opened, and then reused. Renewable fuses
are made to Class H standards.
Resistive Load
An electrical load which is characteristic of
not having any significant inrush current.When a resistive load is energized, the current
rises instantly to its steady-state value, with-
out first rising to a higher value.
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Glossary of Terms
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CatalogSymbol Page
AAO 176
ABC 32
ABCNA 156
ABFNA 156
ABGNA 156
ABWNA 156
AC 177
AD 177
ADLSJ 155
ADOSJ 155
AGA 30
AGC 32
AGU 34
AGW 30
AGX 30
AMWNA 156
ANL 36
ANN 36
ATC 38
ATM 38
B22 43
BAF 22
BAN 22
BAO 176
BBS 21
BC 73, 177
BCCM 79
BC6031 79
BC6032 79
BC6033 79
BD 177
BDAUX 57
BDH 46, 47, 49, 54, 56, 59
BDNF 52, 56
BDS 47, 50, 56
BDST 47BDTA 48, 50
BDTL 48, 50, 57
BDTS 57
BDZX 57
BG 79
BG3011 79
BG3012 79
BG3013 79
BG3021 79
BG3022 79
BG3023 79
BG3031 79
BG3032 79
BG3033 79
BH-0_ _ _ 88, 122, 139
BH-1_ _ _ 88, 122, 139
BH-2_ _ _ 88, 122, 139
BH-3_ _ _ 88, 122, 139
BM 79
BM6031 79
BM6032 79
BM6033 79
BNQ21 107
BP/AGX 189
BP/GLH 189
BP/MAS 189
BP/XMAS 189
BQQ41 107
C515 27
CatalogSymbol Page
C517 27
C518 27
C519 27
C520 27
C5268 122, 142
CAV 156
CAVH 156
CD 177
CDAUX 48
CDBY 54
CDH 45, 47, 53, 55, 59
CDHX 46, 47, 54, 56
CDHXB 49, 59
CDHXY 49, 59
CDHZX 55
CDMC 54
CDN 170
CDNF 51, 53, 55
CDS 45, 46, 53, 54, 170
CDSWM 54
CEO 176
CFC 48
CFD 44, 45, 47
CFTS 48
CFZ 48
CGL 171
CH 80
CIF06 172
CIF21 172
CIH 174
CIK 174
CIL 174
CJ 173
CM_ _CF 174
CS/XMAS 189
CT 141C_ _F 179
DD 177
DEO 176
DIN 124-130
DLN-R 12
DLS-R 12
DRA 196
ED 177
EDA 25
EET 135, 142
EF 177
EFC 58, 59, 60, 61
EFJ 58, 59, 60, 61
EFL 58, 59, 60, 61
EFS 177
EK 172
ENA 25
ENF 62, 63, 64, 65
ERK-28 187
ESD 176
ET 141, 142
FD 44, 49
FDM 190
FE 141, 142
FEE 141, 142
FF 177
FG 177
FL11H _ _ 159
FL11K _ _ 159
CatalogSymbol Page
FL11T _ _ 159
FM 141, 142
FMM 141, 142
FNA 35
FNM 23
FNQ 23
FNQ-R 20
FP 183
FR-1000 186
FRN-R 10, 186
FRS-R 10, 186
FT 183
FWA 116, 143
FWC 145
FWH 31, 118, 144
FWJ 121, 146
FWK 147
FWL 148
FWP 120, 145-146
FWS 148
FWX 117, 144
G 79
GBA 35
GBB 33
GDA 28
GDB 28
GDC 28
GF 177
GG 177
GH 177
GLD 35
GLQ 37
GLR 37
GMA 29
GMC 29
GMD 29GMF 37
GMQ 37
GMT 167
GRF 37
H25 _ _ _ 66
H60 _ _ _ 68
HBH 84
HBV 84
HBW 84
HEB 94
HEC 94
HEG 94
HEH 94
HEJ 94
HET 94
HEX 94
HEY 94
HFA 93
HFB 92
HHB 92
HHC 95
HHD 95
HHF 95
HHG 95
HHL 95
HHM 95
HHT 93
HHX 95
HJL 91
CatalogSymbol Page
HK 91
HKL 91
HKP 86
HKR 91
HKT 91
HKU 91
HKX 91
HLD 91
HLQ 37
HLR 37
HLS 167
HLT 167
HM 93
HME 93
HMF 93
HMG 93
HMH 93
HMI 93
HMJ 93
HO7C 175
HPC-D 90
HPD 89
HPF 18, 89
HPG 89
HPM 90
HPS 89
HR 93
HRC 175, 179
HRE 93
HRF 93
HRG 93
HRH 93
HRI 93
HRJ 93
HRK 92
HTB 87-88HTC-140M 99
HTC-150M 99
HTC-15M 99
HTC-200M 99
HTC-210M 99
HTC-30M 85
HTC-35M 85
HTC-40M 85
HTC-45M 83
HTC-50M 83
HTC-55M 85
HTC-60M 83
HTC-65M 83
HTC-70M 85
HVA 157
HVB 157
HVJ 157
HVL 157
HVR 157
HVT 157
HVU 157
HVW 157
HVX 157
J-_ _ 184
J60030 70
J60060 70
J60100 70
J60200 70
J60400 70
CatalogSymbol Page
J60600 70
JCD 152
JCE 152
JCI 152
JCK 149
JCL 149
JCQ 152
JCT 152
JCU 154
JCW 152
JCX 153
JCY 153
JCZ 154
JDZ 154
JJN 17
JJS 17
JKS 16
JP60030 71
JT(N)60030 72-73
JT(N)60060 72-73
K 26
KAC 119
KAZ 36
KBC 119
KCA 26
KCB 26
KCC 26
KCD 26
KCE 26
KCF 26
KCH 26
KCJ 26
KCM 26
KCR 26
KCS 26
KCY 26KCZ 26
KDA 26
KDB 26
KDC 26
KDD 26
KDE 26
KDF 26
KDH 26
KDJ 26
KDM 26
KDP 26
KDR 26
KDT 26
KDY 26
KEW 26
KEX 26
KFH-A 26
KFM 26
KFT 26
KFZ 26
KIG 26
KLM 22
KLU 6
K07C 175
KPF 26
KQO 26
KQT 26
KQV 26
KRP-C 4-5
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Index by Part Number
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CatalogSymbol Page
KT3 106
KT4 106
KTK 22
KTK-R 20
KTN-R 13
KTQ 21
KTS-R 13
KTU 6
L09C 175
L14C 175
LBS 181
LCT 140
LET 140, 142
LMMT 140, 142
LMT 140, 142
LP-CC 19
LPJ_SP 15
LPN-RK_SP 7-9
LPRK-28 187
LPS-RK_SP 7-9
M09C 175
M14C 175
MAX 38
MDA 34
MDL 33
MDQ 34
MIC 35
MIN 35
MIS 36
MMT 141
MT 141
MV055 151
MV155 151
N512 105
NC3 105
NDN 103NDN1 104
NDN111 104
NDN3 103
NDN63 103
NDNA 48, 104
NDNAS 104
NDNF1 108
NDNLFD1 108
NDNV4 103
NFT2 105
NFT3 105
NFTA 104
NH_G 180
NH_M 180
NH_G-690 180
NITD 176
NNB 184
NNB-R 184
NNC 184
NO. 1 185
NO. 140 188
NO. 15 186
NO. 2 185
NO. 200 189
NO. 201 189
NO. 205 189
NO. 213 184
NO. 216 184
NO. 220 184
CatalogSymbol Page
NO. 226 184
NO. 242 184
NO. 2621 184
NO. 263 184
NO. 2641 184
NO. 2642 184
NO. 2661 184
NO. 2662 184
NO. 2664 184
NO. 270 188
NO. 2880 189
NO. 3 185
NO. 36 187
NO. 4 185
NO. 5 185
NO. 6 185
NO. 626 184
NO. 7 185
NO. 8 185
NON 14
NOS 14
NRA 104
NSD 176
NSE3 105
NSS3 105
NTN-R 184
NTQ23 107
NTS-R 184
NZ_ _ _ 178
OEFMA 158
OEGMA 158
OHFMA 158
OHGMA 158
OLGMA 158
OPM-1038 39-40
OPM-CC 41OPM-SW 41
OPMRH 54
OSD 176
P09C 175
P11C 175
PCT 167
PFD-948 186
PLK3 106
PLU1 106
PLU3 106
PMP 113
PON 170
PS 113
PSU1 106
R11C 175
R25030 66-67
R25060 66-67
R25100 66-67
R25200 66-67
R25400 66-67
R25600 66-67
R60030 68-69
R60060 68-69
R60100 68-69
R60200 68-69
R60400 68-69
R60600 68-69
S 24
S-8000 96
CatalogSymbol Page
SA 25
SAMI 42
SB 181
SC 18
SCY 82
SDLSJ 155
SDMSJ 155
SDQSJ 155
SFC 183
SFLSJ 155
SFMSJ 155
SFQSJ 155
SKA 82
SKLSJ 155
SKMSJ 155
SL 24
SOA72 104
SOU 82
SOW 82
SOX 82
SOY 82
SOY-B 82
SRU 82
SRW 82
SRX 82
SRY 82
SSD 176
SSU 82
SSW 82
SSX 82
SSY 82
SSY-RL 82
SSY-L 82
STD 176
STY 82
T 24 TB 181
T30030 74-75
T30060 74-75
T30100 74-75
T30200 74-75
T60030 76-77
T60060 76-77
T60100 76-77
T60200 76-77
T60400 76-77
T60600 76-77
TDC10 32
TDC11 33
TDC180 31
TDC600 31
TL 24
TP15900-4 161
TP15914 160
TPA 161
TPA-B 161
TPL 164
TPN 165
TPS 162
TPSFH 183
TYPE D (_D_ _ ) 178
UB 108
VFNHA 150
VKNHA 150
VLB 181
CatalogSymbol Page
W 24
WDFHO 150
WDLSJ 150, 155
WDO 124
WDOH6 150
WDOSJ 155
WER 168
WFOH6 150
WFFHO 150
WFLSJ 150, 155
WFMSJ 150
WFNHO 150
WFOSJ 155
WJON6 150
WKFHO 150
WKLSJ 155
WKMSJ 150, 155
WKNHO 150
2499 96
4574 96
11 TYPE 168
11239 78
11240 78
11241 78
11242 78
11675 109
11725 109
14002 109
14004 109
15087 166
15100 163
15149 112
15200 163
15800 162
160_ _ _ 110
162_ _ _ 110163_ _ _ 110-111
165_ _ _ 110
170H_ _ _ _ 138
170M_ _ _ _ 125-137
1A1119 100
1A1120 100
1A1907 100
1A3398 100
1A3399 99
1A3400 101
1A4533 100
1A4534 100
1A5018 99
1A5600 101
1A5601 99
1A5602 99
24 TYPE 168
2NZ01 178
2601 78
2602 78
2604 78
2605 78
2607 78
2608 78
2610 78
2611 78
2960 157
3723 98
3742 98
CatalogSymbol Page
3743 98
3828 97
3835 98
4NZ01 178
4393 97
4421 98
4515 98
4520 97
4528 157
4529 157
4530 157
5591 102
5592 102
5672 102
5674 102
5681 102
5682 102
5956 102
5960 102
5TPH 183
6NZ01 178
64000 26
64200 26
64300 26
64400 26
64600 26
68000 26
68150 26
68200 26
68300 26
68400 26
68600 26
7 TYPE 168
70 SERIES 166
74 TYPE 169
75 TYPE 16976 TYPE 169
8000 96
80 TYPE 169
81 TYPE 168
Bussmann®
Index by Part Number