Mitsubishi NF50-HP, NF30-SP, NF50-HRP, NF60-HP, NF100-SP Technical Notes
...
MOULDED CASE CIRCUIT BREAKERS
TECHNICAL NOTES
ADVANCED AND EVER ADVANCING
00
A
We have the pleasure of providing all our customers with the technical information for Mitsubishi
moulded case circuit breakers. This indicates the fundamental data of our circuit breakers
regarding the applicable standards, constructional principles, and operational performances.
Please refer to the catalogue of our circuit breakers for details of specifications.
Also please stand in need of the handling and maintenance manual for maintaning the circuit
breakers in service continuously.
We do hope they are available for all our customers to built more efficient systems.
CONTENTS
1. INTRODUCTION ...............................................2
2. FEATURES .......................................................3
2.1 Arc-Extinguishing Device – ISTAC.................. 3
2.2 Digital ETR ......................................................... 4
3. CONSTRUCTION AND OPERATION............... 6
4. CHARACTERISTICS AND
PERFORMANCE............................................. 11
4.1 Overcurrent-Trip Characteristics ................... 11
4.2 Short-Circuit Trip Characteristics.................. 11
4.3 Effects of Mounting Attitudes ........................ 12
4.4 DC Tripping Characteristics of AC-Rated
MCCBs.............................................................. 12
4.5 Frequency Characteristics ............................. 12
4.6 Switching Characteristics............................... 13
4.7 Dielectric Strength........................................... 13
5. CIRCUIT BREAKERS SELECTION ............... 14
5.1 Circuit Breakers Selection Table ................... 14
6. PROTECTIVE CO-ORDINATION ................... 39
6.1 General ............................................................. 39
6.2 Interrupting Capacity Consideration ............. 40
6.3 Selective-Interruption...................................... 41
6.4 Cascade Back-up Protection.......................... 46
2
t Let-Through Characteristics and Current
6.5 I
Limiting Characteristics.................................. 48
6.6 Protective Coordination with Wiring ............. 49
6.7 Protective Coordination with
Motor Starters .................................................. 52
6.8 Coordination with Devices on the
High-Voltage Circuit ........................................ 54
7. SELECTION .................................................... 57
7.1 For Motor Branch Circuits .............................. 57
7.2 For Lighting and Heating Branch Circuits .... 57
7.3 For Main Circuit ............................................... 58
7.4 For Welding Circuits ....................................... 58
7.5 For Transformer-Primary Use ........................ 60
7.6 For Capacitor Circuits..................................... 61
7.7 For Thyristor Circuits...................................... 62
7.8 Selection of MCCBs in inverter circuit .......... 68
8. ENVIRONMENTAL CHARACTERISTICS ...... 70
8.1 Atmospheric Environment.............................. 70
8.2 Vibration-Withstand Characteristics ............. 71
8.3 Shock-Withstand Characteristics .................. 72
9. SHORT-CIRCUIT CURRENT
CALCULATIONS ............................................ 73
9.1 Purpose ............................................................ 73
9.2 Definitions ........................................................ 73
9.3 Impedances and Equivalent Circuits of
Circuit Components ........................................ 73
9.4 Classification of Short-Circuit Current.......... 76
9.5 Calculation Procedures .................................. 77
1
1. INTRODUCTION
Mitsubishi Advancing Technology
Mitsubishi, the leading manufacturer of circuit breakers, has been providing customers with a wide range
of highly reliable and safe moulded case circuit breakers (MCCB) and earth-leakage circuit breakers
(ELCB), corresponding to the needs of the age.
Since production began in 1933 many millions of
Mitsubishi ACBs, MCCBs and MCBs have been sold
throughout many countries.
In 1985 a new design concept for controlling arc energies within MCCBs – vapour jet control (VJC) – was
introduced and significantly improved performance. It
is provided the technological advance for a new ‘super series’ range of MCCBs and is used in all present
ratings from 3 to 1600 amps.
In 1995 Mitsubishi offers the new PSS (Progressive
Super Series) breakers having ratings from 3 to 250
amps that concentrate the most advanced technologies into a compact body. Their four major features
are:
• New circuit-breaking technology ISTAC for a higher
current-limiting performance, upgrading the circuitbreaking capability.
• Electronic circuit breakers with the Digital ETR protecting the circuit accurately.
• One-frame, one-size design allowing efficient panel
design.
• Cassette-type internal accessories that allow installation by the user.
Progressive Super Series, an integration of technology and know-how from this comprehensive electronic
product manufacturer, will create its own fields of application with its excellent performance.
A Brief Chronology
1933 Moulded case circuit breaker production
begins.
1952 Miniature circuit breaker production be-
gins.
1968 Manufacture commences of short-time-
delayed breakers.
1969 Production and sale of first residual cur-
rent circuit breakers.
1970 170kA breaking level ‘permanent power
fuse’ integrated MCCBs is introduced.
1973 Introduction of first short-time delay and
current-limiting selectable breakers go on
sale.
1974 First MELNIC solid-state electronic trip
unit MCCBs are introduced.
1975 ELCBs with solid-state integrated circuit
sensing devices are introduced.
1977-1979 Four new ranges of MCCBs are intro-
duced – economy, standard, current limiting, ultra current limiting and motor rated
designs – a comprehensive coverage of
most application requirements.
1982 Compact ACBs with solid-state trip de-
vices and internally mounted accessories
introduced.
1985-1989 Super series MCCBs with VJC and ETR
are developed and launched – awarded
the prestigious Japanese MInister of Construction Prize.
1990 New 200kA level U-series MCCBs super
current limiting breakers are introduced.
1991 Super-NV ELCBs and Super-AE ACBs
are introduced.
1995 Progressive Super Series 30~250 amps
are introduced.
1997 Progressive Super Series 400~800 amps
are introduced.
2
2. FEATURES – Advanced MCCB Design Technol-
ogy & Performance
2.1 Arc-Extinguishing Device – ISTAC
Mitsubishi has developed an epoch-making ISTAC
technology to realize an improved current-limiting and
breaking performance within a smaller breaking space.
Introduction of ISTAC technology upgrades the cur-
rent-limiting, selective-breaking, and cascade-breaking performance. The maximum peak let-through cur-
rent Ip decreases to about 80% (compared with
Mitsubishi’s 100AF). The passing energy I2t decreases to about 65% (compared with Mitsubishi’s
100AF). The smaller breaking space has led to an
improved function, a smaller size, and a standardization of the breakers.
Triple forces accelerating
The triple forces generated by a newly designed current pass and the Vapor Jet Control (VJC) insulating materials which makes up a slot-type breaking
construction accelerate the movable conductor, and
separate the contacts faster than ever before in shortbreaking.
Electromagnetic attractive force which works between
a current of the movable conductor and a current of
the fixed upper conductor.
Electromagnetic repulsive force which works between
a current of the movable conductor and a current of
the fixed lower conductor.
Pressure which works on the movable conductor by
gas generated in the slot.
The VJC suppresses the emergence of carbide products in breaking a current and contribute to the recovery of insulation immediately thereafter.
The VJCs on the fixed and movable contacts work
together to forcefully reduce the arc spot and rapidly
contract the total arc being extinguished.
Movable contact
Upper,
fixed-contact
conductor
Lower,
fixed-contact
conductor
Pressure
Arc
3
Movable
contact VJC
Fixed contact
VJC
Vapor jet control (VJC)
Vapor Jet Controllers made of insulating material are
arranged around the contacts where they control the
arc as follows:
1. The arc spot is forcibly reduced by the arrangement of the insulating material.
2. The arc column is contracted.
3. Adiabatic expansion cools the arc.
4. The arc is transferred at the optimum moment to
the arc-extinguishing chamber by the arrangement
of the Vapor Jet Controllers.
Repulsive
force
Movable
contact
2
1
Attractive
force
Current A
Current B
Current C
Current
Upper,
fixed-contact
conductor
Lower,
fixed-contact
conductor
Arc control by slot-breaking
The VJC of the fixed contact incorporates newly developed insulation made of ceramic fiber and metal
hydroxide. The substantially improves the VJC effect.
The arc-extinguishing gas energies to improve the
capability of extinguishing the arc.
3
2.2 Digital ETR (Electronic Trip Relay)
Sampling and A/D
conversion
Calculating
the digitally
effective value
Processing
the long time-delay
pre-alarm
characteristics
Mitsubishi’s electronic MCCBs are equipped with a
digital ETR to enable fine protection.
The digital ETR contains Mitsubishi’s original double
IC (8 bit microcomputer and custom-IC).
Digital detection of the effective value
Electronic devices such as an inverter distort the current waveform. Mitsubishi’s PSS electronic breakers
are designed to detect digitally the effective value of
the current to minimize over-current tripping errors.
This enables fine protection for the system.
I : Instantaneous
Power-source side terminal
Breaking mechanism
CT
CT
CT
CT
Load-side
terminal
Load-current indication LED (70%)
PSS
Rectifying circuit
WDT
Test input
Trip coil
Custom IC
Microcomputer
I
CV
A/D
convertor
CPU
Characteristics
setting part
SSW
LSW
PSW
Input and
output
circuit
CV : Constant
voltage
circuit
Phaseselection
sampling
circuit
Short
time-delay
soft ware
Trigger circuit
Over-current
indication LED
Pre-alarm
indication LED
Pre-alarm
output
LSW : Long
time-delay
soft ware
PSW : Pre-alarm
soft ware
WDT : Watch-dog
timer
circuit
Processing of the digital ETR
Standard equipped pre-alarm system
Mitsubishi’s PSS electronic breakers have a pre-alarm
system as a standard. When the load current exceeds
the set pre-alarm current, the breaker lights up an LED
and outputs a pre-alarm signal.
4
1×10
3
1×10
I
P
2
1×10
Pre-alarm
10
current
Time (s)
0.1
0.01
1
Load current
4
I
r
10
Current setting
T
L
I
s
T
s
Current (A)
High-voltage fuseAllowable short-time
characteristics
Long time-delay
operating time
Short time-delay
tripping current
Short time-delay
operating time
Instantaneous
tripping current
I
i
2
10
Current-Converted value
on the high-voltage side
Switch
with fuse
High
voltage
Low
voltage
Transformer
MCCB
(electronic)
3
10
M
Load
2.3 Equipment of High Technology
Series
NF-S
NF-C
NF-U
Type
NF30-SP
NF50-HP
NF50-HRP
NF60-HP
NF100-SP
NF100-HP
NF100-SEP
NF100-HEP
NF160-SP
NF160-HP
NF250-SP
NF250-HP
NF250-SEP
NF250-HEP
NF400-SP
NF400-SEP
NF400-HEP
NF400-REP
NF630-SP
NF630-SEP
NF630-HEP
NF630-REP
NF800-SEP
NF800-HEP
NF800-REP
NF1000-SS
NF1250-SS
NF1600-SS
NF50-CP
NF60-CP
NF100-CP
NF250-CP
NF400-CP
NF630-CP
NF800-CEP
NF100-RP
NF100-UP
NF225-RP
NF225-UP
NF400-UEP
NF630-UEP
NF800-UEP
NF1250-UR
ISTAC
●
●
●
●
●
●
●
●
●
●
●
●
Advanced Technology
VJC
Digital-ETR
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
Analog-ETR
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
5
3. CONSTRUCTION AND OPERATION
3.1 General
The primary components are: a switching mechanism,
an automatic tripping device (and manual trip button),
contacts, an arc-extinguishing device, terminals and
a molded case.
Arc-Extinguishing Device
Mitsubishi MCCBs feature excellent arc-extinguishing performance by virtue of the optimum
combination of grid gap, shape,
and material.
Magnetic flux
Grid
Magnetic
force
Arc extinction
Switching Mechanism
The contacts open and close rapidly, regardless of the moving
speed of the handle, minimizing
contact wear and ensuring safety.
Rapid
movement
Arc
Contact
Link-mechanism
operation
Molded case
(Base)
Terminal
Molded case
(Cover)
Automatic tripping device
Handle
1. Trip indication
The automatically tripped condition is indicated by the handle in
the center position between ON
and OFF, the yellow (or white)
line cannot be seen in this position.
2. Resetting
Resetting after tripping is performed by first moving the handle to the OFF position to engage the mechanism, then returning the handle to ON to reclose the circuit.
3. Trip-Free
Even if the handle is held at
ON, the breaker will trip if an
overcurrent flows.
Trip Button (Push to Trip)
Enables tripping mechanically
from outside, for confirming the
operation of the accessory switches and the manual resetting function.
6
Fig. 3.1 Type NF100-SP Construction
ON
ON OFF Trip
4. Contact On Mechanism
Even in the worst case in which
welding occurs owing to an
overcurrent, the breaker will trip
and the handle will maintain to
ON, indicating the energizing
state.
OFF
Handle indication
OFF
ON
3.2 Switching Mechanism
Spring tension line
Toggle link
Cradle
Bracket
Spring
a) On
b) Off
c) Tripped
ON to OFF dead-point line
OFF to ON dead-point line
Handle centered; indicates
tripped condition
The ON, OFF and TRIPPED conditions are shown in
Fig. 3.2. In passing from ON to OFF, the handle tension spring passes through alignment with the toggle
link (“dead point” condition). In so doing, a positive,
rapid contact-opening action is produced; the OFF to
ON contact closing acts in a similar way (“quick make”
and “quick break” actions). In both cases the action of
the contacts is always rapid and positive, and independent of the human element – i.e., the force or
speed of the handle.
In auto tripping a rotation of the bracket releases
the cradle and operates the toggle link to produce the
contact-opening action described above. In the tripped
condition the handle assumes the center position between on and off, providing a visual indication of the
tripped condition. Also, auto trip is “trip free,” so that
the handle cannot be used to hold the breaker in the
ON condition. The protective contact-opening function cannot be defeated.
In multipole breakers the poles are separated by
integral barriers in the molded case. The moving contacts of the poles are attached to the central toggle
link by a common-trip bar, however, so that tripping,
opening and closing of all poles is always simultaneous. This is the “common trip” feature, by which
single phasing and similar unbalance malfunctions are
effectively prevented.
Fig. 3.2 Switching Mechanism Action
3.3 Automatic Tripping Device
There are three types of device, the thermal-magnetic
type, the hydraulic-magnetic type and the electronic
trip relay type.
7
■Automatic Tripping Devices
●Thermal-Magnetic Type (100~630A Frame)
Bimetal
Heater
●Thermal-Magnetic Type (1000~4000A Frame)
Latch
Bimetal
Armature
Heater
Trip bar
Latch
Trip bar
Armature
Stationary core
1. Time-Delay Operation
An overcurrent heats and warps the bimetal to actuate the trip bar.
2. Instantaneous Operation
If the overcurrent is excessive, the
amature is attracted and the trip bar actuated.
Fig. 3.3
1. Time-Delay Operation
An overcurrent heats and warps the bimetal to actuate the trip bar.
2. Instantaneous Operation
If the overcurrent is excessive, magnetization of the stationary core is strong
enough to attract the armature and actuate the trip bar.
Fig. 3.4
●Hydraulic-Magnetic Type (30~60A Frame)
Armature
Trip bar
Pipe
Pole piece
Damping spring
Coil
Silicon oil
Moving core
Fig. 3.5
●Principle of Electronic Trip Relay (ETR) Operation
(100~800A Frame)
Power-source side terminal
Breaking mechanism
Custom IC
CT
CT
CT
Load-side
terminal
CT
CV
PSS
Rectifying circuit
WDT
Test input
Load-current indication LED (70%)
Trip coil
Microcomputer
I
A/D
convertor
CPU
Characteristics
setting part
SSW
LSW
PSW
Input and
output
Trigger circuit
Over-current
indication LED
Pre-alarm
indication LED
Pre-alarm
output
(1000~1600A Frame)
Power-supply side terminal
Switching mechanism
Trip coil
Special IC
Peak
conversion
Rectifier circuit
Test
terminals
and
largest-phase
selection
Effective value
conversion
and
largest-phase
selection
Test-signal
generator
circuit
Overcurrent display
LED
Fig. 3.6
CT
Load-side
terminal
CT
CT
Instantaneous
circuit
Shortdelay
circuit
Longdelay
circuit
1. Time-Delay Operation
At an overcurrent flow, the magnetic
force of the coil overcomes the spring,
the core closes to the pole piece, attracts
the armature, and actuates the trip bar.
The delay is obtained by the viscosity of
silicon oil.
2. Instantaneous Operation
If the overcurrent is excessive, the armature is instantly attracted, without the
influence of the moving core.
1. The current flowing in each phase is
monitored by a current transformer (CT).
2. Each phase of the transformed current
undergoes full-phase rectification in the
rectifier circuit.
3. After rectification, each of the currents
are converted by a peak-conversion and
an effective-value conversion circuit.
4. The largest phase is selected from the
Trigger circuit
converted currents.
5. Each time-delay circuit generates a time
delay corresponding to the largest
phase.
6. The trigger circuit outputs a trigger signal.
7. The trip coil is excited, operating the
switching mechanism.
8
Table 3.1 Comparison of Thermal-Magnetic, Hydraulic-Magnetic and Electronic Types
Item
Operating current is affected by ambient
temperature (bimetal responds to absolute
temperature not temperature rise).
Ambient
temperature
Thermal-magnetic type
Low temperature
Standard temperature
Hydraulic-magnetic type
Affected only to the extent that the damping-oil viscosity is affected.
Low temperature
Negligible effect
Electronic type
Frequency
Distorted
wave
Operating time
High temperature
Current
Negligible effect up to several hundred Hz;
above that the instantaneous trip is affected due to increased iron losses.
Low frequency
High frequency
Operating time
Current
Negligible effect up to 630A;
Above that operating current decreases
due to increase of a fever.
Above 700A
Operating time
Current
Negligible effect.
Operating time
High temperature
Current
Trip current increases with frequency, due
to increased iron losses.
High frequency
Low frequency
Operating time
Current
IF distortion is big, minimum operating current increases.
Small current width
Current width
Operating time
Current
Mounting attitude changes the effective
weight of the magnetic core.
Operating time
Current
Tripping current of some types decrease
due to CT or condition of operating circuit
with high frequency, and others increase.
Operating time
Current
For peak value detection, operating current
drops.
Peak value
detection
Operating time
Current
Negligible effect
Mounting
attitude
Flexibility
of operating
characteristics
Flexibility of
rated current
Operating time
Current
Bimetal must provide adequate deflection
force and desired temperature characteristic. Operating time range is limited.
Operating time
Current
Units for small rated currents are physically
impractical.
Horizontal
ON OFF
Current
OFF
ON
Ceiling
Operating time
Oil viscosity, cylinder, core and spring design, etc., allow a wide choice of operating
times.
Operating time
Current
Coil winding can easily be designed to suit
any ampere rating.
Operating time
Current
Operating time can be easily shortened.
To lengthen operating time is not.
Operating time
Current
Within the range of 50(60)~100% of rated
current, any ampere rating are practical.
Also, to lower the value of short-time delay
or instantaneous trip can be easily done
comparatively.
9
3.4 Contacts
A pair of contacts comprises a moving contact and a
fixed contact. The instants of opening and closing
impose the most severe duty. Contact materials must
be selected with consideration to three major criteria:
1. Minimum contact resistance
2. Maximum resistance to wear
3. Maximum resistance to welding
Silver or silver-alloy contacts are low in resistance,
but wear rather easily. Tungsten, or majority-tungsten
alloys are strong against wear due to arcing, but rather
high in contact resistance. Where feasible, 60%+ silver alloy (with tungsten carbide) is used for contacts
primarily intended for current carrying, and 60%+ tungsten alloy (with silver) is used for contacts primarily
intended for arc interruption. Large-capacity MCCBs
employ this arrangement, having multicontact pairs,
with the current-carrying and arc-interruption duties
separated.
3.5 Arc-Extinguishing Device
Arcing, an inevitable aspect of current interruption,
must be extinguished rapidly and effectively, in normal switching as well as protective tripping, to minimize deterioration of contacts and adjacent insulating materials. In Mitsubishi MCCBs a simple, reliable,
and highly effective “de-ion arc extinguisher,” consisting of shaped magnetic plates (grids) spaced apart in
an insulating supporting frame, is used (Fig. 3.7). The
arc (ionized-path current) induces a flux in the grids
that attracts the arc, which tends to “lie down” on the
grids, breaking up into a series of smaller arcs, and
also being cooled by the grid heat conduction. The
arc (being effectively longer) thus requires far more
voltage to sustain it, and (being cooler) tends to lose
ionization and extinguish. If these two effects do not
extinguish the arc, as in a very large fault, the elevated
temperature of the insulating frame will cause gassing-out of the frame material, to de-ionize the arc.
Ac arcs are generally faster extinguishing due to the
zero-voltage point at each half cycle.
3.8 Trip Button
This is a pushbutton for external, mechanical tripping
of the MCCB locally, without operating the externalaccessory shunt trip or undervoltage trip, etc. It enables easy checking of breaker resetting, control-circuit devices associated with alarm contacts, etc., and
resetting by external handle.
Supporting
frame
Grids
Fig. 3.7 The De-Ion Arc Extinguisher
Induced flux
Grid
Attraction force
Fig. 3.8 The Induced-Flux Effect
Arc
3.6 Molded Case
The integral molded cases used in Mitsubishi MCCBs
are constructed of the polyester resin containing glass
fibers, the phenolic resin or glass reinforced nylon.
They are designed to be suitably arc-, heat- and gasresistant, and to provide the necessary insulating
spacings and barriers, as well as the physical strength
required for the purpose.
3.7 Terminals
These are constructed to assure electrical efficiency
and reliability, with minimized possibility of localized
heating. A wide variety of types are available for ease
of mounting and connection. Compression-bonded
types and bar types are most commonly used.
10
Rated current
(A)
30 or less
31~63
64~100
101~250
251~400
401~630
631~800
801~1000
1001~1250
1251~1600
1601~2000
2001~4000
Tripping time
(minutes, max.)
200%
8.5
4
8.5
8
10
12
14
16
18
20
22
24
130%
60
60
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
60
60
120
105%
Non-Tripping time
(minutes, max.)
4. CHARACTERISTICS AND PERFORMANCE
4.1 Overcurrent-Trip Characteristics (Delay
Tripping)
Tripping times for overcurrents of 130 and 200% of
rated current are given in Table 4.1, assuming ambient temperatures of 40°C, a typical condition inside
of panelboards. The figures reflect all poles tested together for 130% tripping, and 105% non-tripping.
Within the range of the long-delay-element (thermal
or hydraulic) operation, tripping times are substantially linear, in inverse relationship to overcurrent magnitude.
The tripping times are established to prevent excessive conductor-temperature rise; although times
may vary among MCCBs of different makers, the lower
limit is restricted by the demands of typical loads: tungsten-lamp inrush, starting motor, mercury-arc lamps,
etc. The tripping characteristics of Mitsubishi MCCBs
are established to best ensure protection against abnormal currents, while avoiding nuisance tripping.
4.1.1 Ambient Temperature and Thermal Tripping
Fig. 4.1 is a typical ambient compensation curve
(curves differ according to types and ratings), showing that an MCCB rated for 40°C ambient use must
be derated to 90% if used in a 50°C environment. In
an overcurrent condition, for the specified tripping time,
tripping would occur at 180% rated current, not 200%.
At 25°C, for the same tripping time, tripping would
occur at 216%, not 200%.
4.1.2 Hot-State Tripping
The tripping characteristics described above reflect
“cold-state tripping” – i.e., overloads increased from
zero – and the MCCB stabilized at rated ambient. This
is a practical parameter for most uses, but in intermittent operations, such as resistance welding, motor
pulsing, etc., the “hot state” tripping characteristic must
be specified, since over-loads are most likely to occur with the MCCB in a heated state, while a certain
load current is already flowing.
Where the MCCB is assumed to be at 50% of rating when the overload occurs, the parameter is called
the 50% hot-state characteristic; if no percentage is
specified, 100% is assumed. Hot-state ratings of 50%
and 75% are common.
4.2 Short-Circuit Trip Characteristics (In-
stantaneous Tripping)
For Mitsubishi MCCBs with thermal-magnetic trip units
the instantaneous-trip current can be specified independently of the delay characteristic, and in many
cases this parameter is adjustable offering considerable advantage in coordination with other protection
and control devices. For example, in coordination with
motor starters, it is important to set the MCCB instantaneous-trip element at a lower value than the fusing
(destruction) current of the thermal overload relay
(OLR) of the starter.
For selective tripping, it must be remembered that
even though the branch-MCCB tripping time may be
shorter than the total tripping time of the main MCCB,
in a fault condition the latter may also be tripped because its latching curve overlaps the tripping curve of
the former. The necessary data for establishing the
required compatibility is provided in the Mitsubishi
MCCB sales catalogues.
The total clearing time for the “instantaneous” tripping feature is shown in Fig. 4.3; actual values differ
for each MCCB type.
Table 4.1 Overcurrent Tripping Times
120
110
108
100
20 25
% rating compensation
Fig. 4.1 Typical Temperature-Compensation Curve
Hot state
Operating time
Fig. 4.2 Hot-State-Tripping Curve
40
30
90
80
Ambient temperature (:)
Cold state
Current
50 60
11
Total
clearing
time
Fig. 4.3 Instantaneous Tripping Sequence
Latching
(relay)
time
Electromagnet
oparating
time
Floor-mounted
Mechanical
delay
time
Time for
contacts to
open
Arcing
time
Arcextinguishing
time
4.3 Effects of Mounting Attitudes
Instantaneous tripping is negligibly affected by mounting attitude, for all types of MCCB. Delay tripping is
also negligibly affected in the thermal types, but in
the hydraulic-magnetic types the core-weight effect
becomes a factor. Fig. 4.4 shows the effect, for vertical-surface mounting and for two styles of horizontalsurface mounting.
(vertical plane)
100%
Wall-mounted
(horiz. or vert. attitude)
Ceiling-mounted
Tripping time
Overcurrent
Fig. 4.4 Effect of Mounting Attitude on the Hydraulic-
Magnetic MCCB Tripping Curves
Fig. 4.5 Effects of Nonvertical-Plane Mounting on Current
4.4 DC Tripping Characteristics of AC-Rated MCCBs
Table 4.2 DC Tripping Characteristics
Trip unit
Thermal
magnetic
Hydraulic
magnetic
Long delay
No effect below 630A
frame. Above this, AC
types cannot be used
for DC.
DC minimum-trip
values are 110~140%
of AC values.
Instantaneous
DC inst.-trip current is
approx. 130% of AC
value.
107%
107%
Rating
ON
ON
ON
ON
ON
ON
100%
93%
ON
ON
93%
Tripping curve
AC
Tripping time
Tripping time
DC
Overcurrent
AC
DC
Overcurrent
90%110%
4.5 Frequency Characteristics
At commercial frequencies the characteristics of
Mitsubishi MCCBs of below 630A frame size are virtually constant at both 50Hz and 60Hz (except for the
E Line models, the characteristics of MCCBs of 2000A
frame and above vary due to the CT used with the
delay element).
At high frequencies (e.g., 400Hz), both the current
capacity and delay tripping curves will be reduced by
skin effect and increased iron losses.
Performance reduction will differ for different types;
at 400Hz it will become 80% of the rating in breakers
of maximum rated current for the frame size, and 90%
12
of the rating in breakers of half of the maximum rating
for the frame size.
The instantaneous trip current will gradually increase with frequency, due to reverse excitation by
eddy currents. The rise rate is not consistent, but
around 400Hz it becomes about twice the value at
60Hz. Mitsubishi makes available MCCBs especially
designed for 400Hz use. Apart from operating characteristics they are identical to standard MCCBs (S
Line).
4.6 Switching Characteristics
Frame size
100 or less
225
400, 630
800
1000~2000
2500, 3000
3200, 4000
Operations per hour
120
120
60
20
20
10
10
Number of operations
Without current
8500
7000
4000
2500
2500
1500
1500
With current
1500
1000
1000
500
500
500
500
Total
10000
8000
5000
3000
3000
2000
2000
The MCCB, specifically designed for protective interruption rather than switching, and requiring high-contact pressure and efficient arc-extinguishing capability, is expected to demonstrate inferior capability to
that of a magnetic switch in terms of the number of
operations per minute and operation life span. The
specifications given in Table 4.3 are applicable where
the MCCB is used as a switch for making and break-
Table 4.3 MCCB Switching Endurance
ing rated current.
Electrical tripping endurance in MCCBs with shunt
or undervoltage tripping devices is specified as 10%
of the mechanical-endurance number of operations
quoted in IEC standards.
Shunt tripping or undervoltage tripping devices are
intended as an emergency trip provision and should
not be used for normal circuit-interruption purposes.
4.7 Dielectric Strength
In addition to the requirements of the various international standards, Mitsubishi MCCBs also have the
impulse-voltage withstand capabilities given below
(Table 4.4). The impulse voltage is defined as sub-
Table 4.4 MCCB Impulse Withstand Voltage (Uimp)
Type
NF
Line
MB
MB30-CS
MB30-SP MB50-CP MB50-SP
MB100-SP MB225-SP
NF30-SP NF50-HP NF60-HP
NF50-HRP NF100-SP NF100-HP NF100-SEP NF100-HEP
NF160-SP NF160-HP NF250-SP NF250-HP NF250-SEP NF250-HEP
S
NF400-SP NF400-SEP NF400-HEP NF400-REP NF630-SP NF630-SEP
NF630-HEP NF630-REP NF800-SEP NF800-HEP NF800-REP
NF800-REP NF1000-SS NF1250-SS NF1600-SS
NF30-CS
NF50-CP NF60-CP NF100-CP NF250-CP
C
NF400-CP NF630-CP NF800-CEP
NF100-RP NF100-UP NF225-RP NF225-UP
U
NF400-UEP NF630-UEP NF800-UEP
stantially square-wave, with a crest length of
0.5~1.5µsec and a tail-length of 32~48µsec. The voltage is applied between line and load terminals (MCCB
off), and between live parts and ground (MCCB on).
Impulse-voltage (kA)
4
6
6
8
4
6
8
6
8
13
5. CIRCUIT BREAKER SELECTION
5.1 Circuit Breaker Selection Table
Following Table shows various characteristics of each breaker to consider selection and coordination with
upstream devices or loads.
Characteristics
Standard : Standard characteristics MCCBs
Low-inst : Low-inst. MCCBs for Discrimination
When a power fuse (PF) is used as a high-voltage protector, it must be coordinated
with an MCCBs on the secondary side.
PF short-time tolerancs
capacity
Pf.
MCCB
operating
characteristic
curve
Tr.
MCCB1
MCCB2
Generator: Generator-Protection MCCBs
These MCCBs have long-time-delay operation shorter than standard type and low
instantaneous operation.
Mag-Only : Magnetic trip only MCCBs
These are standard MCCBs minus the thermal tripping device. They have no timedelay tripping characteristic, providing protection only against large-magnitude shortcircuit faults.
Low-inst.MCCBs
Time
Current
14
CIRCUIT BREAKER SELECTION TABLE
Frame (A)
Type
Rated current In (A)
Rated insulation voltage Ui (V) AC
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
Standard
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
690V
500V
440V
400V
230V
Hydraulic-magnetic
Fixed ampere rating and
instantaneous
NF30-CS
3, 5, 10, 15, 20, 30
500
–
–
1.5/1.5 (415V)
1.5/1.5 (380V)
2.5/2 (240V)
23
339± 17
566± 28
10 132 ± 57
15 198 ± 86
20 265 ± 115
30 397 ± 172
30
NF30-SP
3, 5, 10, 15, 20, 30
600
–
2.5/1
2.5/1
5/2
5/2
23
Hydraulic-magnetic
Fixed ampere rating and
instantaneous
333± 10
555± 17
10 110 ± 35
15 165 ± 52
20 220 ± 70
30 330 ± 105
50
NF50-CP
10, 15, 20, 30, 40, 50
600
–
2.5/1
2.5/1
5/2
5/2
23
Hydraulic-magnetic
Fixed ampere rating and
instantaneous
10 110 ± 35
15 165 ± 52
20 220 ± 70
30 330 ± 105
40 440 ± 140
50 550 ± 175
Low-inst
Generator
Mag-Only
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
–
–
–
–
–
–
–
Magnetic
–
–
Fixed ampere rating
instantaneous
330± 6
550± 10
10 100 ± 20
15 150 ± 30
20 200 ± 40
30 300 ± 60
–
–
–
–
–
–
23
Magnetic
Fixed ampere rating
instantaneous
10 100 ± 20
15 150 ± 30
20 200 ± 40
30 300 ± 60
40 400 ± 80
50 500 ± 100
–
–
–
–
–
–
23
15
Frame (A)
Type
Rated current In (A)
Rated insulation voltage Ui (V) AC
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
Standard
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
690V
500V
440V
400V
230V
50
NF50-HP
10, 15, 20, 30, 40, 50
600
–
7.5/4
10/5
10/5
25/13
234
Hydraulic-magnetic
Fixed ampere rating and
instantaneous
10 110 ± 35
15 165 ± 52
20 220 ± 70
30 330 ± 105
40 440 ± 140
50 550 ± 175
60
NF60-CP
10, 15, 20, 30, 40, 50, 60
600
–
2.5/1
2.5/1
5/2
5/2
23
Hydraulic-magnetic
Fixed ampere rating and
instantaneous
10 110 ± 35
15 165 ± 52
20 220 ± 70
30 330 ± 105
40 440 ± 140
50 550 ± 175
60 660 ± 210
Low-inst
Generator
Mag-Only
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
–
–
–
–
–
–
234
Magnetic
Fixed ampere rating and
instantaneous
10 100 ± 20
15 150 ± 30
20 200 ± 40
30 300 ± 60
40 400 ± 80
50 500 ± 100
–
–
–
–
–
–
23
Magnetic
Fixed ampere rating and
instantaneous
10 100 ± 20
15 150 ± 30
20 200 ± 40
30 300 ± 60
40 400 ± 80
50 500 ± 100
60 600 ± 120
16
Frame (A)
Type
Rated current In (A)
Rated insulation voltage Ui (V) AC
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
Standard
Low-inst
Generator
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
690V
500V
440V
400V
230V
Hydraulic-magnetic
Fixed ampere rating and
instantaneous
60
NF60-HP
10, 15, 20, 30, 40, 50, 60
600
–
7.5/4
10/5
10/5
25/13
234
10 110 ± 35
15 165 ± 52
20 220 ± 70
30 330 ± 105
40 440 ± 140
50 550 ± 175
60 660 ± 210
–
–
–
–
–
100
NF100-CP NF100-SP
50, 60, 75, 100
600
–
7.5/4
10/5
10/5
25/13
23
Thermal, magnetic
Fixed ampere rating and
instantaneous
50 750 ± 150
60 900 ± 180
75 1125 ± 225
100 1500 ± 300
23
Thermal, magnetic
Fixed ampere rating and
instantaneous
50 300 ± 60
60 360 ± 72
75 450 ± 90
100 600 ± 120
–
–
15, 20, 30, 40, 50, 60, 75, 100
Thermal, magnetic
Fixed ampere rating and
instantaneous
100 1500 ± 300
Thermal, magnetic
Fixed ampere rating and
instantaneous
100 600 ± 120
690
–
15/8
25/13
30/15
50/25
234
15 225 ± 45
20 300 ± 60
30 450 ± 90
40 600 ± 120
50 750 ± 150
60 900 ± 180
75 1125 ± 225
234
15 90 ± 18
20 120 ± 24
30 180 ± 36
40 240 ± 48
50 300 ± 60
60 360 ± 72
75 450 ± 90
–
–
Mag-Only
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
–
234 2 3
Magnetic
Fixed ampere rating and
instantaneous
10 100 ± 20
15 150 ± 30
20 200 ± 40
30 300 ± 60
40 400 ± 80
50 500 ± 100
60 600 ± 120
Magnetic
Fixed ampere rating and
instantaneous
100 1000 ± 200
–
50 500 ± 100
60 600 ± 120
75 750 ± 150
–
234
Magnetic
Fixed ampere rating and
instantaneous
15 150 ± 30
20 200 ± 40
30 300 ± 60
40 400 ± 80
50 500 ± 100
60 600 ± 120
75 750 ± 150
100 1000 ± 200
17
Frame (A) 100
Type
Rated current In (A)
Rated insulation voltage Ui (V) AC
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
Standard
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
690V
500V
440V
400V
230V
Thermal, magnetic
Adjustable ampere rating
and fixed instantaneous
NF100-CP T/A
15 ~ 20, 20 ~ 25, 25 ~ 40
40 ~ 63, 63 ~ 80, 80 ~ 100
600
–
7.5/4
10/5
10/5
25/13
23
15 ~ 20 225 ± 45
20 ~ 25 300 ± 60
25 ~ 40 375 ± 75
40 ~ 63 600 ± 120
63 ~ 80 945 ± 189
80 ~ 100 1200 ± 240
50
NF50-HRP
15, 20, 30, 40, 50
690
2.5/1
20/10
30/15
30/15
85/43
23
Thermal, magnetic
Fixed ampere rating and
instantaneous
15 225 ± 45
20 300 ± 60
30 450 ± 90
40 600 ± 120
50 750 ± 150
100
NF100-SP T/A
15 ~ 20, 20 ~ 25, 25 ~ 40
40 ~ 63, 63 ~ 80, 80 ~ 100
690
–
15/8
25/13
30/15
50/25
234
Thermal, magnetic
Adjustable ampere rating
and fixed instantaneous
15 ~ 20 225 ± 45
20 ~ 25 300 ± 60
25 ~ 40 375 ± 75
40 ~ 63 600 ± 120
63 ~ 80 945 ± 189
80 ~ 100 1200 ± 240
Low-inst
Generator
Mag-Only
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
–
–
–
–
–
–
–
–
–
Magnetic
Fixed ampere rating and
instantaneous
15 150 ± 30
20 200 ± 40
30 300 ± 60
40 400 ± 80
50 500 ± 100
–
–
–
–
–
–
23
–
–
–
–
–
–
–
–
–
18
Frame (A)
Type
Rated current In (A)
15, 20, 30, 40, 50, 60, 75, 100
100
NF100-HP T/ANF100-HP
15 ~ 20, 20 ~ 25, 25 ~ 40
40 ~ 63, 63 ~ 80, 80 ~ 100
NF100-RP
15, 20, 30, 40, 50, 60, 75, 100
Rated insulation voltage Ui (V) AC
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
Standard
Low-inst
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
690V
500V
440V
400V
230V
690
5/3
30/15
50/25
50/25
100/50
234
Thermal, magnetic
Fixed ampere rating and
instantaneous
15 225 ± 45
20 300 ± 60
30 450 ± 90
40 600 ± 120
50 750 ± 150
60 900 ± 180
75 1125 ± 225
100 1500 ± 300
–
–
690
5/3
30/15
50/25
50/25
100/50
234
Thermal, magnetic
Adjustable ampere rating
and fixed instantaneous
15 ~ 20 225 ± 45
20 ~ 25 300 ± 60
25 ~ 40 375 ± 75
40 ~ 63 600 ± 120
63 ~ 80 945 ± 189
80 ~ 100 1200 ± 240
–
–
690
–
42/42
125/125
125/125
125/125
23
Thermal, magnetic
Fixed ampere rating and
instantaneous
15 225 ± 45
20 300 ± 60
30 450 ± 90
40 600 ± 120
50 750 ± 150
60 900 ± 180
75 1125 ± 225
100 1500 ± 300
–
–
Generator
Mag-Only
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
–
–
–
–
234
Magnetic
Fixed ampere rating and
instantaneous
15 150 ± 30
20 200 ± 40
30 300 ± 60
40 400 ± 80
50 500 ± 100
60 600 ± 120
75 750 ± 150
100 1000 ± 200
–
–
–
–
–
–
–
–
–
–
–
–
–
–
19
Frame (A)
Type
Rated current In (A)
Rated insulation voltage Ui (V) AC
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
Standard
Low-inst
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
690V
500V
440V
400V
230V
Thermal, magnetic
Fixed ampere rating and
instantaneous
NF100-UP NF100-SEP
15, 20, 30, 40, 50, 60, 75, 100
690
10/5
200/200
200/200
200/200
200/200
234
15 225 ± 45
20 300 ± 60
30 450 ± 90
40 600 ± 120
50 750 ± 150
60 900 ± 180
75 1125 ± 225
100 1500 ± 300
–
–
15 ~ 20, 30 ~ 50, 60 ~ 100
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up, and instantaneous
Short time delay pick up current
Variation is within ±15% of
setting current
15 30-37.5-45-52.5-60-7520 40-50-60-70-80-100-12030 60-75-90-105-120-15040 80-100-120-140-16050 100-125-150-175-20060 120-150-180-210-24075 150-187.5-225-262.5-300-
100 200-250-300-350-400-
Instantaneous pick up current
Variation is within ±15% of
setting current
30 ~ 50 200 ~ 800
60 ~ 100 400 ~ 1600
100
690
–
15/8
25/13
30/15
50/25
34
2 to 10 Ir
90-105-120-150
140-160-200
180-210-240-300
200-240-280-320-400
250-300-350-400-500
300-360-420-480-600
375-450-525-600-750
500-600-700-800-1000
4 In ~ 16 In
–
–
NF100-HEP
15 ~ 20, 30 ~ 50, 60 ~ 100
690
5/3
30/15
50/25
50/25
100/50
34
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up, and instantaneous
Short time delay pick up current
Variation is within ±15% of
setting current
2 to 10 Ir
15 30-37.5-45-52.5-60-75-
90-105-120-150
20 40-50-60-70-80-100-120-
140-160-200
30 60-75-90-105-120-150-
180-210-240-300
40 80-100-120-140-160-
200-240-280-320-400
50 100-125-150-175-200-
250-300-350-400-500
60 120-150-180-210-240-
300-360-420-480-600
75 150-187.5-225-262.5-300-
375-450-525-600-750
100 200-250-300-350-400-
500-600-700-800-1000
Instantaneous pick up current
Variation is within ±15% of
setting current
4 In ~ 16 In
30 ~ 50 200 ~ 800
60 ~ 100 400 ~ 1600
–
–
Generator
Mag-Only
20
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
–
–
Electronic trip relay
–
–
–
–
–
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up, and instantaneous
Rating: 15 ~ 20A, 30 ~ 50A,
Inst. : Operating characteristics
–
3
60 ~ 100A
must be adjusted as
follows.
STD q 3 (Is setting)
LTD : minimum setting
L = 12sec setting)
(T
–
–
–
–
3
Electronic trip relay
Adjustable ampere rating
Adjustable long time delay
operating time, short time delay
pick up, and instantaneous
Rating: 15 ~ 20A, 30 ~ 50A,
60 ~ 100A
Inst. : Operating characteristics
must be adjusted as
follows.
STD q 3 (Is setting)
LTD : minimum setting
L = 12sec setting)
(T
–
–
–
Frame (A)
Type
Rated current In (A)
Rated insulation voltage Ui (V) AC
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
Standard
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
690V
500V
440V
400V
230V
Thermal, magnetic
Fixed ampere rating and
instantaneous
NF160-SP
125, 150, 160
690
–
15/8
25/13
30/15
50/25
234
125 1750 ± 350
150 2100 ± 420
160 2240 ± 448
160
NF160-SP T/A
100 ~ 125, 125 ~ 160
690
–
15/8
25/13
30/15
50/25
234
Thermal, magnetic
Adjustable ampere rating and
fixed instantaneous
100 ~125 1400 ± 280
125 ~ 160 1400 ± 280
NF160-HP
125, 150, 160
690
5/3
30/8
50/13
50/13
100/25
234
Thermal, magnetic
Fixed ampere rating and
instantaneous
125 1750 ± 350
150 2100 ± 420
160 2240 ± 448
Low-inst
Generator
Mag-Only
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
–
–
–
–
–
–
234 234
Magnetic
Fixed ampere rating and
instantaneous
125 1250 ± 250
160 1600 ± 320
–
–
–
–
–
–
–
–
Magnetic
Fixed ampere rating and
instantaneous
125 1250 ± 250
160 1600 ± 320
–
–
–
–
–
–
–
21
Frame (A)
Type
Rated current In (A)
160
NF160-HP T/A
125, 150, 175, 200, 225, 250100 ~ 125, 125 ~ 160
NF250-CP
250
NF250-CP T/A
100 ~ 125, 125 ~ 160
150 ~ 200, 200 ~ 250
Rated insulation voltage Ui (V) AC
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
Standard
Low-inst
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
690V
500V
440V
400V
230V
Thermal, magnetic
Adjustable ampere rating
and fixed instantaneous
690
5/3
30/8
50/13
50/13
100/25
234
100 ~ 125 1400 ± 280
125 ~ 160 1400 ± 280
–
–
–
600
–
10/5
15/8
18/9
30/15
23
Thermal, magnetic
Fixed ampere rating and
instantaneous
125 1750 ± 350
150 2100 ± 420
175 2450 ± 490
200 2800 ± 560
225 3150 ± 630
250 2500 ± 500
23
Thermal, magnetic
Fixed ampere rating and
instantaneous
6 In 4 In
125 750 ± 150 500 ± 100
150 900 ± 180 600 ± 120
175 1050 ± 210 700 ± 140
200 1200 ± 240 800 ± 160
225 1350 ± 270 900 ± 180
250 1500 ± 300 1000 ± 200
600
–
10/5
15/8
18/9
30/15
23
Thermal, magnetic
Adjustable ampere rating
and fixed instantaneous
100 ~ 125 1400 ± 280
125 ~160 1400 ± 280
150 ~200 2100 ± 420
200 ~250 2500 ± 500
–
–
–
Generator
Mag-Only
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
–
–
–
–
Magnetic
–
–
Fixed ampere rating and
instantaneous
125 1250 ± 250
150 1500 ± 300
175 1750 ± 350
200 2000 ± 400
225 2250 ± 450
250 2250 ± 450
–
–
–
23
–
–
–
–
–
–
22
Frame (A)
Type
Rated current In (A)
Rated insulation voltage Ui (V) AC
AC Breaking
capacity (kA rms)
IEC60947-2
Icu/Ics
Standard
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
690V
500V
440V
400V
230V
Thermal, magnetic
Fixed ampere rating and
instantaneous
NF250-SP
125, 150, 175, 200, 225, 250
690
–
15/8
25/13
30/15
50/25
234
125 1750 ± 350
150 2100 ± 420
175 2450 ± 490
200 2800 ± 560
225 3150 ± 630
250 2500 ± 500
250
NF250-SP T/A
100 ~ 125, 125 ~ 160
150 ~ 200, 200 ~ 250
690
–
–
25/20
30/22
50/42
234
Thermal, magnetic
Adjustable ampere rating
and fixed instantaneous
100 ~125 1400 ± 280
125 ~ 160 1400 ± 280
150 ~200 2100 ± 420
200 ~250 2500 ± 500
NF250-HP
125, 150, 175, 200, 225, 250
690
5/3
30/8
50/13
50/13
100/25
234
Thermal, magnetic
Fixed ampere rating and
instantaneous
125 1750 ± 350
150 2100 ± 420
175 2450 ± 490
200 2800 ± 560
225 3150 ± 630
250 2500 ± 500
Low-inst
Generator
Mag-Only
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
Number of poles
Automatic tripping
device
Rating (A) and
Inst. (A)
234
Thermal, magnetic
Fixed ampere rating and
instantaneous
6 In4 In
125 750 ± 150 500 ± 100
150 900 ± 180 600 ± 120
175 1050 ± 210 700 ± 140
200 1200 ± 240 800 ± 160
225 1350 ± 270 900 ± 180
250 1500 ± 300 1000 ± 200
–
–
–
234
Magnetic
Fixed ampere rating and
instantaneous
125 1250 ± 250
150 1500 ± 300
175 1750 ± 350
200 2000 ± 400
225 2250 ± 450
250 2250 ± 450
–
–
–
–
–
–
–
Magnetic
–
–
Fixed ampere rating and
instantaneous
125 1250 ± 250
150 1500 ± 300
175 1750 ± 350
200 2000 ± 400
225 2250 ± 450
250 2250 ± 450
–
–
–
–
–
–
234
23
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