(Miniature Circuit Breaker)

Features :
l Uniform 10KA breaking capacity for ‘B’ and ‘C’ Curve
l Low power consumption, thus cost effective & energy saving
l Suitable for DC and for a wide frequency range of 50Hz - 400Hz application
l “Finger Safe” terminals - IP 20 degree of protection
l Dual Termination facility
l 15 Plate Arc Chute for effective arc quenching
l Silver Graphite contacts for enhanced life
l Accessories - Auxiliary Switch
- Shunt Trip
Miniature Circuit Breaker

CONSTRUCTION

Miniature Circuit Breakers have precision formed moulded case & cover of flame retardant high strength thermo plastic material having high
melting point, low water absorption, high dielectric strength and temperature with stand.
The Switching mechanism is independent, manual, and is trip free, i.e., the breaker trips internally even if the operating knob is held in ON
position.
The Contact mechanism comprises of fixed and moving contacts made of silver graphite for reliability, long life and anti-weld properties.
The Arc Extinguishing Device comprises of 15 plates arc chute. The arc under the influence of the magnetic field and arc guide is moved into
the arc chute where it is rapidly split and quenched.
The tripping mechanism is Thermal Magnetic type.
Thermal Operation
The thermal operation provides protection from moderate overloads. Under overload condition a thermo-metal element (bimetallic strip) deflects
until it operates a latching mechanism allowing the main contacts to open.
Magnetic operation
In magnetic operation, large overloads or short circuit current actuates a solenoid causing a plunger to strike the latching mechanism rapidly
opening the main contacts.

INTERNAL VIEW

Outgoing Terminal
Bimetal Carrier

Bimetal Strip
Latch

Arc-chutes Holder
Solenoid
Arc-chutes
Knob / Dolly
Arc-runner

Moving Contact Arm

Plunger
Fixed Contact

Incoming Terminal
(Dual Termination)
 Miniature Circuit Breaker

TECHNICAL INFORMATION

MCB ISOLATOR

Standard Conformity IS: 8828: 96 & IEC: 60898: 2002 IS: 13947-3: 93 & IEC: 60947-3: 2001
Type/Series B C D#
Rated Current (In) A 6 - 63* 0.5 - 63* 0.5 - 63* 40 - 63
Rated Voltage (ac) (Ue) V 240/415 240/415 240/415 240/415
Rated Frequency (f) Hz 50 50 50 50
Nos. of Poles (Execution) 1P, 1P+N, 2P, 3P, 3P+N, 4P** 1P, 2P, 3P, 4P**
Rated Short Circuit Breaking Capacity kA 10 10 4.5
Utilization Category AC 22A
Magnetic Release Setting (3-5)In (5-10)In (10-20)In -
Rated Insulation Voltage (Ui) V 660 660 660 660
Rated Impulse Voltage (Uimp) kV 4 4 4 4
Electrical / Mechanical Endurance
(no. of operations)
Less than 32A 20,000 20,000 20,000
More than 32A 10,000 10,000 10,000 10,000
Ambient Temperature (oC) -5 to +55 -5 to +55 -5 to +55 -5 to +55
Terminal Capacity (max) sq.mm 25 25 25 25
Vibration g 3 3 3 5
Shock 40mm free fall 40mm free fall 40mm free fall 40mm free fall
Protection Class IP-20
Installation Position Vertical / Horizontal
Mounting Clip on DIN Rail (35mm x 7.5mm)
Case & Cover Moulded, flame retardant thermoplastic material.

* Current Ratings - 0.5, 1, 2, 3, 4, 5, 6, 8, 10, 13, 16, 20, 25, 32, 40, 50, 63 ** 1P Single Pole
# ‘D’ Curve MCBs are available on request 1P+N Single Pole Neutral
2P Double Pole
3P Three Pole
3P+N Three Pole Neutral
4P Four Pole
Miniature Circuit Breaker

ACCESSORIES

AUXILIARY CONTACT

Attachment used for signalling, indication, Annunciation and interlocking

Standard Conformity : IS: 13947 - 1: 93

Rated Current (In) A : 6
Rated Voltage (Ue) V ac : 240
Conact Configuration : 1 NO + 1 NC / 2 NO + 2 NC
Utilization Category : AC 11
Rated Impulse Voltage (Uimp) kV : 6
Electrical Endurance (nos. of operations) : 10000
Terminal Capacity (max) mm2 : 10
Protection Class : IP - 20 as per IEC-60529 / IS-2147
Mounting : Left side of MCB
(Factory assembled)

SHUNT TRIP

Attachment used for remote tripping.

Standard Conformity : IS: 13947 - 1: 93

Coil Consumption VA : 6
Rated Voltage (ac) (Ue) V : 240
(dc) (Ue) V : 48, 24, 12
Frequency Hz : 50
Operating Voltage range : 70% - 110% of rated voltage
Rated Impulse Voltage (Uimp) kV : 6
Electrical Endurance (nos. of ops) : 10000
Terminal Capacity (max) mm2 : 25
Protection Class : IP - 20 as per IEC-529 / IS-2147
Mounting : Right side of MCB
(Factory assembled)

Shunt Trip Connection Shunt Trip Coil

Diagram 1. To trip the Circuit Breaker through Shunt Trip Coil, 70% to 110% of the rated
Outgoing Coil Terminal voltage is to be applied across D1 & D2

2. The Shunt Trip coil is short time rated and trip the breaker instantaneously
(i.e., continuous duty not required)

Incoming

Incoming Connection
 Miniature Circuit Breaker

CHARACTERISTICS CURVES

Thermal Tripping Magnetic Tripping

As per No tripping Tripping Time Hold Trip Time
IS:8828:96 current current Limits current current Limits
I1 I2 t I4 I5 t

B Curve 1.13 x IN >1h 3xIN >0.1s

1.45 x IN <1h 5 x IN <0.1s

C Curve 1.13 x IN >1h 5xIN >0.1s

1.45 x IN <1h 10 x IN <0.1s
B Curve
C Curve D Curve 1.13 x IN >1h 10xIN >0.1s
D Curve
1.45 x IN <1h 20 x IN <0.1s

l3 = 2.55 x lN 1 s < t < 60s for lN < 32A

1 s < t < 120s for lN > 32A

, ,

TRIPPING CHARACTERISTICS

Based on the Tripping Characteristics, MCBs are available in ‘B’, ‘C’ and ‘D’ curve to suit different types of applications.
‘B’ Curve: for protection of electrical circuits with equipment that does not cause surge current (lighting and distribution circuits)
Short circuit release is set to (3 - 5) In
‘C’ Curve: for protection of electrical circuits with equipment that causes surge current (inductive loads and motor circuits)
Short circuit release is set to (5 - 10) In
‘D’ Curve: for protection of electrical circuits which causes high inrush current, typically 12-15 times the thermal rated current (transformers,
X-ray machines etc.) Short circuit release is set to (10 - 20) In

CURRENT LIMITING DESIGN

In a current limiting breaker, the tripping mechanism & arc control is so designed
that under short circuit conditions, the contacts are physically separated and
the electrodynamic forces set up by fault current assist the extinction in less
than half cycle.
The figure shows the current limiting effect of a circuit breakers.
Fault Traces for Voltage & Current
0 = Point of fault initiation
tx = Contact opening time (i.e., creation of arc)
t1 = Current / Voltage peak (i.e., current limitation)
t2 = Time to total extinction of arc
(i.e., complete shutdown of fault current)
Miniature Circuit Breaker

HAMMER TRIP MECHANISM

Current Limiting design in itself may not fulfill the requirement of quick
breaking (instantaneous action) mainly due to inertia of the Latch
mechanism and interconnected sequence of operations.
A Hammer directly connected to the plunger strikes the moving contact
arm with a force proportional to the peak current there by forcibly
separating the moving contact from the fixed contact much before the
latch mechanism operates. This further reduces the opening time of the
circuit breaker.

Plunger
Hammer

AMBIENT TEMPERATURE COMPENSATION / DIVERSITY FACTOR CHART

Maximum Permissible Rated Current Diversity Factor

(K1 Factor) (K2 Factor)
K1 K2

Graph 1 Graph 2

Calculation In / switch = K1 x K2 x In
Example 4 MCBs with In = 10A, and the amb. temp. is 50oC kept with no gap in between
Solution K1 =0.89 (from graph 1)
K2 =0.78 (from graph 2)
In / pole = 0.89 x 0.78 x 10 = 6.94 A

EFFECT OF FREQUENCY VARIATION

MCBs are designed to operate at AC frequency 50 / 60 Hz. However MCBs specially suitable for DC applications and for frequencies upto
400 A can be supplied on request.
These can be used on different frequencies in supply from 16 2/3 - 60 Hz without any deration.
For higher frequencies, normal MCBs can be used with a multiplication factor which shall only affect its magnetic trip current.

Supply AC DC
Frequency 100Hz 200Hz 400Hz
Multiplication Factor 1.1 1.2 1.5 1.5
 Miniature Circuit Breaker

LET THROUGH ENERGY I 2T

MAXIMUM BACKUP PROTECTION

At site, no. of MCB are used for outgoing connection. To protect the MCBs under short circuit (higher capacity), we need to put fuses in the
incoming side. The current rating of fuses should not be more than the values given in the table below.
MCB Backup
Current Rating Fuse Rating
1 25
2 35
4 50
6 80
10-63 100

COLD RESISTANCE & POWER LOSS DETAILS

The power loss value declared are at rated current.

Rated Current Cold Resistance Power Loss per Pole

IN (A) RI (m33. ) Pv (W)
1 1178 1.3
2 281 1.5
4 92 2.2
6 16.55 0.7
10 11.68 1.4
13 10.1 1.7
16 8.0 2.2
20 5.25 2.5
25 3.78 3.1
32 2.57 3.4
40 1.94 3.9
63 1.40 7.3
Miniature Circuit Breaker

DC APPLICATION

Eurobreaker for DC application are specially designed to meet tough arc quenching
conditions. While selecting circuit breaker for DC applications following parameters
have to be taken into consideration.

Normal Circuit Currents

The rating and normal running temperature of the MCB are unaffected by DC. The
MCB can be selected using the thermal section of the standard time / current curves .

Magnetic tripping on DC is different from the equivalent AC by a peak factor of 1.4

ie., for ‘B’ curve AC MCB, magnetic range = (3-5) ln
for DC MCB, magnetic range = 1.4(3-5)ln = (4-7)ln
for ‘C’ curve AC MCB, magnetic range = (5-10)ln
for DC MCB, magnetic range =1.4(5-10)ln =(7-14)ln

Short Circuit Currents

The maximum short circuit current possible on a DC system is determined by the voltage of the battery and the total internal resistance of the
cells. It is given by Ohm’s law :

Isc = Vb
Rb

where, Isc is the Short Circuit Current

Vb is the voltage of the battery (with the battery 100% charged)
Rb is the internal resistance of the battery cells
(this is usually stated by the manufacturer)

Circuit Time Constant

L
The time constant is given by :
R
where L is the inductance of the circuit
R is the resistance of the circuit
The time constant is usually given in milliseconds (ms.). ideally, DC circuits would be mainly resistive (ie. a low number), as inductive circuits
produce a back emf when the current suddenly falls. This in turn tends to prolong arcing during switching operations, and so reduce contact life.

Circuit Voltage
The voltage of the circuit is dependent upon the power supply. The lower the voltage the easier switching operations will be, but the voltage makes
no difference to the running of the MCB’s

Contact life can be significantly increased by reducing the voltage drop accross each pole. This can be acheived by wiring poles in series.

Eurobreaker MCB’s have been successfully tested on DC and can be used under the following conditions :
L/R 15ms max
Voltage 12-130V
Short circuit breaking capacity 1 KA
Magnetic release Setting 4-7 ln
 Miniature Circuit Breaker

DISCRIMINATION DATA

MCBs MCB Upstream C Curves

downstream
C curve 10A 13A 16A 20A 25A 32A 40A 50A 63A
0.5 to 5A 50 65 80 100 125 160 200 250 315
6A 65 80 100 125 160 200 250 315
10A 100 125 160 200 250 315
13A 125 160 200 250 315
16A 160 200 250 315
20A 200 250 315
25A 250 315
32A 315
40A
50A

MCBs MCB Upstream B Curves

downstream
B curve 6A 10A 13A 16A 20A 25A 32A 40A 50A 63A
0.5 to 5A 30 39 48 60 75 96 120 150 189
6A 30 39 48 60 75 96 120 150 189
10A 48 60 75 96 120 150 189
13A 60 75 96 120 150 189
16A 75 96 120 150 189
20A 96 120 150 189
25A 120 150 189
32A 189
40A
50A

Discrimination with Fuses

HRC Fuse upstream type Gg

MCBs HRC Fuse Link Upstream

downstream 20A 25A 32A 40A 50A 63A 80A 100A 125A 160A
0.5 to 6A 700 850 960 1200 1350 1750 2800 4500 5200 6000
10A 700 960 1200 1350 1750 2800 4500 5200 6000
13A 850 1200 1200 1750 2800 4500 5200 6000
16A 960 1100 1500 2500 3200 5200 6000
20A 1100 1500 2500 3200 4500 5200
25A 960 1350 2000 3200 4500 5200
32A 1200 1750 2800 4500 5200
40A 1750 2800 4500 5200
50A 2500 3200 4500
63A 3200 4500
Miniature Circuit Breaker

SELECTION CHART

Rating of MCBs for specified No. of Fittings

For Household Applications (“B” Series MCBs)

Appliances Capacity / Current Rating Type of MCB Lamp Number of Lamps Rating (A)
watt (Load) of MCB (Watt)
(230VAC 1ph) 20W 8 1
Air Conditioner 1.0 tonnes 10.0A “C” series 12 1.5
1.5 tonnes 16.0A “C” series 40W 2 0.5
2.0 tonnes 20.0A “C” series 10 2
Refrigerator 165 litres 3.0A “C” series 12 2.5
350 litres 4.0A “C” series 60W 1 0.5
Oven cum Griller 4500W 25.0A “B” series 4 1.5
1750W 10.0A “B” series 8 3
12 4
Oven only 750W 6.0A “B” series
Hot plate only 2000W 10.0A “B” series 80W 1 0.5
Room Heater 1000W 6.0A “B” series 2 1
2000W 10.0A “B” series 5 2
8 4
Washing Machine 300W 2.0A “C” series
12 5
Washing Machine
(with heater) 1300W 8A “C” series 100W 1 1
2 1.5
Water Heater
4 2.5
(storage/instant) 1000W 6.0A “B” series
2000W 10.0A “B” series
3000W 16.0A “B” series
6000W 32.0A “B” series
Electric iron 750W 6.0A “B” series
1250W 8A “B” series
Auto toaster
(2 slices) 1200W 6.0A “B” series
Electric Kettle 1500W 10.0A “B” series “B” series MCB is used for all lighting Applications

For Motor Applicatons (Three Phase)

Calculation Formulae :
Motor kW MCB Ratings
HP Star Delta DOL
Incomer Current Rating, For Single Phase : Total Load in Watts
1.0 0.75 - 2A 220 V
1.5 1.10 - 3A
2.0 1.50 - 4A Incomer Current Rating, For Three Phase : Total Load in Watts
3 x 220V
3.0 2.25 - 6A
5.0 3.75 10A 10A
6.0 4.50 10A 10A
7.5 5.50 16A 16A
10.0 7.50 16A 16A
12.5 9.30 20A 20A
15.0 11.00 25A 25A
17.5 13.00 25A 32A
20.0 15.00 32A 40A
25.0 18.50 40A 50A
30.0 22.50 50A 50A
35.0 26.00 63A 63A

Note : One lighting circuit can have upto 800W or upto 10 lighting points
“C” series MCB is used for all Motor Applications One power circuit can have upto 2000W or 1 power points
 Miniature Circuit Breaker

SINGLE POLE
Current ‘B’ Curve ‘C’ Curve ‘DC’ MCB.* ‘DC’ Rly Appl.#
rating (A) Cat No. Cat No. Cat No. Cat No.
0.5 MCCSP0.5 MCDSP0.5 MCRSP0.5
1 MCCSP001 MCDSP001 MCRSP001
2 MCCSP002 MCDSP002 MCRSP002
3 MCCSP003 MCDSP003 MCRSP003
4 MCCSP004 MCDSP004 MCRSP004
5 MCCSP005 MCDSP005 MCRSP005
6 MCBSP006 MCCSP006 MCDSP006 MCRSP006
10 MCBSP010 MCCSP010 MCDSP010 MCRSP010
16 MCBSP016 MCCSP016 MCDSP016 MCRSP016
20 MCBSP020 MCCSP020 MCDSP020 MCRSP020
32 MCBSP032 MCCSP032 MCDSP032 MCRSP032
35 MCDSP035 MCRSP035
40 MCBSP040 MCCSP040 MCDSP040 MCRSP040
50 MCBSP050 MCCSP050 MCDSP050 MCRSP050
63 MCBSP063 MCCSP063 MCDSP063 MCRSP063
SINGLE POLE - N

Current ‘B’ Curve ‘C’ Curve

rating (A) Cat. No. Cat. No.
0.5 MCCSN0.5
1 MCCSN001
2 MCCSN002
3 MCCSN003
4 MCCSN004
5 MCCSN005
6 MCBSN006 MCCSN006
10 MCBSN010 MCCSN010
16 MCBSN016 MCCSN016
20 MCBSN020 MCCSN020
32 MCBSN032 MCCSN032
40 MCBSN040 MCCSN040
50 MCBSN050 MCCSN050
63 MCBSN063 MCCSN063

DOUBLE POLE

Current ‘B’ Curve ‘C’ Curve ‘DC’ Appl.

rating (A) Cat No. Cat No. Cat No.
0.5 MCCDP0.5 MCDDP0.5
1 MCCDP001 MCDDP001
2 MCCDP002 MCDDP002
3 MCCDP003 MCDDP003
4 MCCDP004 MCDDP004
5 MCCDP005 MCDDP005
6 MCBDP006 MCCDP006 MCDDP006
10 MCBDP010 MCCDP010 MCDDP010
16 MCBDP016 MCCDP016 MCDDP016
20 MCBDP020 MCCDP020 MCDDP020
32 MCBDP032 MCCDP032 MCDDP032
40 MCBDP040 MCCDP040 MCDDP040
50 MCBDP050 MCCDP050 MCDDP050
63 MCBDP063 MCCDP063 MCDDP063

* MCB suitable for DC application. # MCB specially designed for Railway application fitted with extended terminals and mounting brackets.
Miniature Circuit Breaker

THREE POLE

Current ‘B’ Curve ‘C’ Curve

rating (A) Cat. No. Cat. No.
0.5 MCCTP0.5
1 MCCTP001
2 MCCTP002
3 MCCTP003
4 MCCTP004
5 MCCTP005
6 MCBTP006 MCCTP006
10 MCBTP010 MCCTP010
16 MCBTP016 MCCTP016
20 MCBTP020 MCCTP020
32 MCBTP032 MCCTP032
40 MCBTP040 MCCTP040
50 MCBTP050 MCCTP050
63 MCBTP063 MCCTP063

THREE POLE - N

Current ‘B’ Curve ‘C’ Curve

rating (A) Cat. No. Cat. No.
0.5 MCCTN0.5
1 MCCTN001
2 MCCTN002
3 MCCTN003
4 MCCTN004
5 MCCTN005
6 MCBTN006 MCCTN006
10 MCBTN010 MCCTN010
16 MCBTN016 MCCTN016
20 MCBTN020 MCCTN020
32 MCBTN032 MCCTN032
40 MCBTN040 MCCTN040
50 MCBTN050 MCCTN050
63 MCBTN063 MCCTN063

FOUR POLE

Current ‘B’ Curve ‘C’ Curve

rating (A) Cat. No. Cat. No.
0.5 MCCFP0.5
1 MCCFP001
2 MCCFP002
3 MCCFP003
4 MCCFP004
5 MCCFP005
6 MCBFP006 MCCFP006
10 MCBFP010 MCCFP010
16 MCBFP016 MCCFP016
20 MCBFP020 MCCFP020
32 MCBFP032 MCCFP032
40 MCBFP040 MCCFP040
50 MCBFP050 MCCFP050
63 MCBFP063 MCCFP063
 Miniature Circuit Breaker

ACCESSORIES

SHUNT TRIP
Description Cat. No.
12 VDC MCDST012
24 VDC MCDST024
48 VDC MCDST048
240 VAC MCAST240

AUXILIARY CONTACT
Contact Configuration Current Cat. No.
1NO + 1NC 6 Amp. MCBAC116
2NO + 2NC 6 Amp. MCBAC226
 Isolators

SINGLE POLE
20
Current Rating (A) Cat. No.
40 MI0SP040
63 MI0SP063

DOUBLE POLE

Current Rating (A) Cat. No.

40 MI0DP040
63 MI0DP063

THREE POLE

Current Rating (A) Cat. No.

40 MI0TP040
63 MI0TP063
 Isolators

FOUR POLE
21
Current Rating (A) Cat. No.
40 MI0FP040
63 MI0FP063

DIMENSIONS ( IN MM)

A
SP SPN DP TP TPN FP
MCBs 17.8 35.6 35.6 53.4 71.2 71.2
Isolators 17.8 35.6 53.4 71.2
Auxiliary contact 9
Shunt Trip 17.8