2. Miniature Circuit Breakers (MCBs) : Type 5SX4
General
Betagard 5SX4 range of MCBs
have rated breaking capacity of
10kA. They comply to the latest
national and international
standards, with current ratings
from 0.5A to 63A.
For applications in industry and
in system and plant
engineering, add-on
accessories are available, such
as auxiliary contacts (AC), fault-
signal contacts (FC) and shunt
trips (ST).
Short circuit operation
At high values of overcurrent
(i.e. short circuit current) a
plunger in the solenoid is
moved with sufficient force to
physically separate the is between 3 to 5 milliseconds. Standards • Finger Touch Proof
contacts. The greater the short The energy let through (I²t) of Terminals, provide
According to IS 8828 (1996),
circuit current, the greater the the device is kept to a installation safety.
IEC 60898 (1995), VDE 0641/
force with which the plunger is minimum thus offering a very 6.78. • Totally safe and dependable
moved and faster the circuit is high degree of protection. - computer calibrated
disconnected. A secondary Features at a glance testing.
action will ensure that the Current limiting class 3 • Recessed ON – OFF lever
• Current limiting class 3 type
circuit breaker mechanism is 5SX4 type MCBs significantly ensuring no accidental
breakers.
limit the let-through current operation.
• “C” / “D” tripping
(when a fault occurs) due to
characteristics. • Combined terminals allow
the ultra – fast contact
• Service life : Average 20,000 busbar and feeder cable to
separation and the quick
operations at rated load. be simultaneously
quenching of the emergency
connected.
arc in the chamber. Thus, • Suitable for AC and DC
generally, they fall below the circuits. • ON-OFF Lever sealable in
permissible limiting I²t values ON and OFF position.
• Wide range of Add on
of the energy limiting class 3, accessories. • Can be mounted in any
specified in DIN VDE 0641 Part position.
• Trip Free mechanism.
II by 50%. This guarantees
excellent discrimination with • Better selectivity.
the upstream protective devices
and reduces the thermal stress Current Limiting Class
on the downstream connected Rated Current
according to EN 60898
tripped and prevents the equipments.
contacts from reclosing. It is 1 2 3
Chart indicates the let through
the rapid speed with which the
energy values of 10kA, 16A
contacts are forced apart 16 A Permissible let-through I²t (A²S)
MCB according to EN 60898.
coupled with other features of
MCBs, which provides the This MCB (16Amps) will allow No limit 2,90,000 84,000
Current limiting capability and only 50% of 84,000 (A²S) let-
safe interruption up to 10,000A. through energy thereby
The rapid speed at which the reducing thermal stress to bare
contacts are parted prevents minimum value on the
the fault current from reaching downstream equipment.
its prospective value. The arc As these MCBs meet the
drawn between the contacts is requirements of current
moved by magnetic forces into limiting class 3, according to
the multiple plate arc chamber EN 60898 without difficulty,
where the arc is split, rapidly they are therefore marked with
cooled and extinguished. The symbol 10000
total operating time of the MCB 3
2
3. Rated Breaking Capacity :
As per IEC
60898 / IS 8828 As per IEC 60947-2 As per UL 489
Rated 1P, 2P, 3P, 4P 1P 2P, 3P, 4P 1P, 2P, 3P, 4P 1P, 2P, 3P, 4P
Current In (A) 230V AC, 415V 230V AC 230V AC, 415 AC, 415 AC,
Icn (kA) Icn (kA) Icn (kA) Icn (kA) Icn (kA)
5SX4 0.5 - 6 10 50 50 50 50
10 - 20 10 25 30 25 50
25 - 32 10 20 25 20 50
40 - 63 10 10 15 10 –
‘C’ Characteristics capacitive loads including most up to 5 times In, (rated current) operating limits (for short-
‘C’ characteristics MCBs are motor and fluorescent lighting and can hence be used to best circuit operations) are between
used for protection of electrical loads. advantage for handling higher 5 and 10 times the rated
circuits in general and are most This characteristic allows inrush currents e.g. lamps, current (In) of MCB. For
widely used because of its applying loads having high motors, etc. Under ‘C’ example the instantaneous
suitability for practically all peak currents without requiring characteristics, the magnetic mechanism of a 10A MCB will
electrical circuits, cable and the MCB to be oversized. In
line protection. They are fact, thanks to this Number 1 2 ... 3 4 ... 6 >7
capable of supplying the characteristic, it is possible to
apply loads with peak currents Correction factor K 1.00 0.90 0.88 0.85
majority of inductive and
Tripping Characteristics : C Tripping Characteristics : D
3
4. operate between 50A and Frequency Variation ensure correct sizing of the current, which should, where
100A in an overcurrent MCBs may be used up to their device wherein high inrush possible, provide selectivity.
situation. The thermal normal voltage rating on currents are prevailing. Selectivity means, that in the
operating limits (for overload 400Hz supplies; however the This characteristics allows to event of a fault, only the
operation) are between 1.13 magnetic tripping characteristic use in a high in rush current protective device in the vicinity
and 1.45 of the rated current must be increased by 30% (e.g. circuits without requiring the of the fault trips. Thus, parallel
(In) of the MCB. Type ‘C’ MCB with magnetic MCB to be over sized. current paths can continue to
characteristics between 5 and D characteristics MCB shall provide the necessary power.
Effect of Higher Operating
10 times the rated current take the in rush current with For MCBs with upstream fuses,
Voltages would become between 6.5 peak up to 10 times In, (Rated the selectivity limit essentially
Betagard MCB is designed to and 13 times rated current. current) and can be used best depends on the current limits
operate at 240/415V, 50Hz. advantage for handling much and tripping characteristics of
However the device can Effect of temperature on higher in rush circuits the MCB as well as on the pre-
operate at 480V, 50Hz with a tripping characteristics : eg: Switching solenoids/ arcing I²t value of the fuse.
reduction in breaking capacity Betagard MCBs are designed to capacitor banks/transformers Therefore, MCBs with different
of 50%. meet the requirements of IS etc. characteristics and rated
8828 / IEC 60898 for tripping Under D characteristics, the breaking capacities also have
DC Operation different selectivity limits. The
performance at ambient magnetic operating limits (for
Single pole MCBs can be used temperature 30°C. At other subsequent tables show the
short circuit operations) are
up to 60V DC and double pole operating temperature the currents up to which selectivity
between 10 to 20 times the
up to 110V DC. overload tripping band is is provided between MCBs and
rated current of MCB.
However, they should not be modified by approximately 5% upstream fuses according to
For example the instantaneous DIN VDE 0636 Part 21. The
used below 18V DC. Though per 10° kelvin temperature
mechanism of 10A MCB will values specified in kA are limit
the thermal operation is difference, which increases for
operate between 100A and values which have been
delayed but this is negligible. lower and decreases for higher
200A in an over current determined under unfavourable
The instantaneous tripping temperatures than 30°C.
situation. test conditions. In practice,
characteristic must be
increased by 40% (e.g. a Type “D” Characteristics better values can be obtained,
Selectivity of miniature
‘C’ MCB has a magnetic tripping D characteristics MCBs are depending on the type of the
circuit-breakers/fuses upstream fuse.
characteristic between 5 and used for protection of electrical
10 times the rated current. This circuits involving significant Generally, distribution networks In the event of a short circuit,
magnetic tripping characteristic inrush currents like solenoid are configured as radial when using the 5SX4, MCBs
would therefore become valves, capacitor banks, networks. An overcurrent device and fuses according to DIN VDE
between 7 and 14 times the transformers, etc. must be provided at each 0636 Part 21, Selectivity is
rated current. reduction of the conductor cross provided up to the indicated
The main use of D section. This results in a cascade
characteristics MCBs is to values in kA.
graded according to the rated
Limit values of the MCBs / Fuses selectivity in kA
Downstream Upstream fuses
MCBs In[A] 16 A 20 A 25 A 35 A 50 A 63 A 80 A 100 A 125 A
Characteristic C ≤2 0.3 0.5 1.5 2.0 9.0 • • • •
4 0.3 0.4 0.9 1.4 3.5 5.0 9.0 • •
6 – 0.4 0.8 1.4 2.7 4.5 6.0 • •
10 – – 0.5 1.2 2.0 3.0 4.2 7.0 •
16 – – – 1.0 1.5 2.2 3.0 6.0 •
20 – – – – 1.3 2.2 3.0 6.0 •
25 – – – – – 2.2 2.9 5.0 9.0
32 – – – – – – 2.4 4.0 7.0
40 – – – – – – 2.0 3.5 4.0
50 – – – – – – – 3.0 4.0
63 – – – – – – – 3.0 3.5
• Rated breaking capacity 5SX4 acc. to IEC 60898 10000
4
5. Selectivity of MCBs / themselves within close limits. The following table specifies
Circuit-breakers This depends on the peak the short-circuit currents in kA
current Î of the downstream up to which selectivity is
In distribution networks
MCB and on the tripping provided between MCBs
without any fuses, MCBs
current of the upstream MCB. connected in series at 230V AC.
provide selectivity between
Limit values of the MCBs / circuit-breakers selectivity in kA
Downstream Upstream circuit-breakers
MCBs 5SX4 …- 7
Characteristic C
In[A] 20 25 32 40 50
I >[A] 200 250 320 400 500
Icn[kA] 10 10 10 10 10
Selectivity limits [kA] 1)
Characteristic C 0.5 5 10 0.2 0.3 0.5 0.8 0.8
1 10 10 0.2 0.3 0.5 0.8 0.8
2 20 10 0.2 0.3 0.5 0.8 0.8
4 40 10 0.2 0.2 0.3 0.5 0.5
6 60 10 0.2 0.2 0.3 0.5 0.5
10 100 10 0.2 0.2 0.3 0.4 0.4
16 160 10 0.2 0.2 0.3 0.4 0.4
20 200 10 – 0.2 0.3 0.4 0.4
25 250 10 – – – 0.3 0.4
32 320 10 – – – 0.3 0.4
40 400 10 – – – – –
50 500 10 – – – – –
63 630 10 – – – – –
I> = Tripping current
1) In 240/415V, 50 Hz the selectivity limits must be reduced by 10%. Maximum value In = rated current.
Selectivity of MCBs / Moulded Case Circuit Breakers
Limit values of the MCBs / MCCBs selectivity in kA
Upstream circuit-breakers
VF100/125 VL160X VL250N VL250H VL400N VL400H VL630N VL630H VL800N VL800H
Downstream Rated current
100/125A 160A 200/250A 315/400A 400/500/630A 800A
Circuit-breakers in (A)
Trip Unit TM TM TM / ETU TM / ETU TM / ETU TM / ETU TM / ETU TM / ETU ETU ETU
Breaking capacity
18 / 25kA 40 / 70kA 40kA 70kA 45kA 70kA 45kA 70kA 50kA 70kA
lcn (kA)
Selectivity limits (kA)
5SX4 20 TM 10kA 3.8 10 10 10 10 10 10 10 10 10
25 / 32 TM 10kA 3 9.1 10 10 10 10 10 10 10 10
40 / 63 TN 10kA 2.1 4.8 6.5 6.5 10 10 10 10 10 10
5
6. Back-up protection, MCBs/ or if the specified rated prevents excessive stressing of up to which back-up protection
Fuses breaking capacity is exceeded, the MCB. Generally, a fuse is is ensured if SIEMENS MAKE
an additional protective device used for this purpose. DIN fuses are used acc. to DIN
If the level of the maximum
must be connected upstream The following table specifies VDE 0636 Part 21.
short circuit current flowing at
as backup protection. This the short-circuit currents in kA
the MCB location is unknown,
Limit values of the MCBs/Fuses selectivity in kA
Downstream Upstream fuses
MCBs In[A] 50 A 63 A 80 A 100 A 125 A 160 A
5SX4
0.5 - 4 no back-up protection required up to 50kA
6 50 50 50 50 50 35
10 50 50 50 50 50 35
16 50 50 50 35 30 30
20 50 50 50 35 25 25
25 50 50 50 35 30 25
32 50 50 50 35 30 25
40 50 50 50 50 25 15
50 50 50 50 50 25 15
63 50 50 35 25 25 15
Test circuit data: Test cycle:
Up = 250 V Acc. to 60 947 - 2(O - CO)
cos φ = 0.3 to 0.5
6
7. Data Overview 5SX4 MCBs
Product data sheet
Standards IS 8828 (1996), IEC 60 898, VDE 0641/6.78
Series 5SX4 / 5SJ4
Tripping characteristics ‘C’ / ‘D’
No. of poles SP, SPN, DP, TP, TPN & FP*
240 / 415 V AC, 50/60 Hz
Rated voltage Volts
SP – 60V DC, DP – 110V DC
Current Range Amps 0.5 – 63
Operational voltage min. AC/DC V 24
max. DC V/Pole 60
max. AC V 440
Rated Breaking Capacity
acc. to IS 8828 / IEC 60898, DIN VDE 0641 AC kA 10
Insulation coordination
Rated insulation voltage 250/440 V AC
Degree of pollution for overvoltage category III 2
Mounting on a 35 mm mounting rail (EN 50 022)
Conductor cross sections
Solid and stranded, max.
Upper terminal mm² 16
Lower terminal mm² 25
Finely stranded with end sleeves, max.
Upper terminal mm² 16
Lower terminal mm² 25
Terminal tightening torque
(power driver setting) Nm 2.5 - 3
Supply connection As required, top or bottom.
Mounting position As required in any position.
Endurance On an average 20,000 operations at rated load
Ambient temperature °C -25 to +45, occasionally +55 max. 95% humidity,
Storage temperature : -40 to +75
Resistance to climate According to IEC 68-2-30, 6 cycles
Resistance to vibration m/s² 60 at 10 to 150 Hz according to IEC 68-2-6
* FP available only in 63A
7
10. Add-on Accessories
For applications in industry and electrically independent combined slotted and Shunt trip (ST)
in system and plant contacts (separated electrical podzidrive head screws. The shunt trip coil allows the
engineering, add-on circuits); one of these contacts circuit breaker to be remotely
accessories are available, such is normally open and the other Fault signal contacts (FC) tripped. The coil and circuit
as auxiliary contacts (AC), fault- normally closed. The The fault signal contact block breaker are coupled together
signal contacts (FC), shunt trips mechanically stable position of has a structure and dimensions not only by using the control
(ST). ST is mounted left of the contacts does not change identical to those of the handle, but also with the
MCB. AC/FC are mounted on unless the circuit-breaker is auxiliary contact block (AC). internal trigger.
right side. These modules can manually actuated or is tripped The fault signal contact block
be used as inputs/outputs to a due to an overload or a short remotely indicates the tripping
PLC, building-automation circuit. The terminals are of device due to an overload or
system etc. for signalling and characterised by a degree of a short-circuit. The block’s
control. protection IP 2X; they allow contact remain in position
connecting conductors with a when the circuit-breaker’s
Auxiliary contacts (AC) maximum cross-section of 2.5 handle is manually actuated.
Each block consists of two mm² and are delivered with
Auxiliary Contact (AC) Fault Signal Contact
AC Type Ref Type Ref FC Type Ref Type Ref
(5SX4) (5SJ4) (5SX4) (5SJ4)
1NO+1NC 5SX9100 5ST3010 1NO+1NC 5SX9200 5ST3020
2NO 5SX9101 – Applications : Remotely indicating the
tripping condition of the MCB
Applications : Remotely indicating the
switching condition of the MCB ON/OFF • Can be subsequently mounted to
the MCB.
• Can be subsequently mounted to
the MCB. • Mounted using factory installed
clips.
• Mounted using factory installed
clips. • Max. contact load :
6A, 230 V AC, AC-15
• Max. contact load :
1 A, 220 V DC, DC-13
6A, 230 V AC, AC-15
1 A, 220 V DC, DC-13 • Cable size upto
1 x 2.5 sq mm to be used.
• Cable size upto
1 x 2.5 sq mm to be used.
Shunt trip (ST) Dimensions in mm
Shunt Type Ref Type Ref
Release (5SX4) (5SJ4)
110…415VAC 5SX9300 5ST3030
24…48VDC – 5ST3031
Applications : Remotely tripping the
MCB. 100% switch-on duration.
• Mounted using attached screws.
1MW = 18mm
• Can be used for voltages 110 to 415
V AC, Short-circuit protection using
MCB. Maximum Possible Configurations for Accessories
10
11. Carefree life due to enhanced safety
B
>AJ=C=H@
• 10kA breaking capacity insures protection for bigger
installations
• Type AC / Type A versions for protection in residential,
commercial and industrial buildings I
• Space saving in distribution boards due to compact width
For more details: 11
mail to: switches.india@siemens.com Fax: +91 22 2762 3729
