MCB / MCCB / ELCB Quick Reference (Part-2)

November 16, 2018 7 Comments

 

Selection of MCB
MCB curve Type of Load Residential Commercial
B curve Resistive Loads Incandescent lights Incandescent lights
Geyser  Boilers
 Heater  Heaters
Fan blower heaters Oil radiator heaters
Slight Inductive Loads Florescent Lights Florescent lights
Small motors (FHP) High pressure mercury vapor lamps
C curve Slight Inductive Loads Fans & small pumps Sodium vapor lamps
Window / Split ACs
Lights with ballasts
 Microwave
 Refrigerators
 General household equipment
D curve Inductive Loads Water lifting pumps Florescent lights
UPS ID & FD fans
Small control transformers
Medium size motors
Refrigerators for commercial use

 

Type of MCB
MCB Curve Type of Load Response Tripping Application Uses
B curve Resistive loads MCBs react quickly to overloads 3 To 5 times F.L current (0.04 To 13 Sec) Domestic & Commercial applications Suitable for incandescent lighting, socket-outlet, bulbs, heaters etc. Protection of DG sets (since DG sets have low short-circuit capacity)
C curve Slightly inductive loads MCBs react more slowly, 5 To 10 times F.L current  (0.04 To 5 Sec) Commercial and Industrial applications

 

 Highly Inductive loads such as motors, air conditioners, fluorescent lighting lights, fans & household electrical appliances.
D curve Inductive loads MCBs are slower 10 To 20 times F.L current  (0.04 To 3 Sec) Commercial and Industrial applications

 

 Very high inrush Inductive currents, Small transformers, welding machines. UPS, small motor & pumps, x-ray machines etc. Note, however, that MCBs with Type K characteristics may provide better protection in some applications of this type.
K curve Inductive loads MCBs are slower 8 To 10 times F.L current  (0.04 To 3 Sec) Placing them between the traditional Type C and Type D breakers. In most cases, they allow improved cable protection to be provided in circuits that include motors, capacitors and transformers, where it would previously have been necessary to use Type D devices. This enhanced protection is achieved without increasing the risk of nuisance tripping.

 

Selection of RCCB
Type of RCCB Sensitive Application
Type AC Sensitive to AC Currents Only Suitable for most domestic and commercial applications.
Type A Sensitive to AC Currents + Pulsating DC Currents (Produced by Rectifier, Thyristors) Used where there are a lot of “electronic” loads, such as computer equipment or lighting systems with electronic ballasts.
Type B Sensitive to AC Currents + Pulsating DC Currents+ Pure DC Currents Use in photovoltaic (PV) solar energy installations because the PV panels produce a DC Output and some types of fault can result in the leakage of DC Currents to Earth.
Type B+ Similar to Type B, but respond to ac leakage currents over a wider frequency range Type B and Type B+ devices can be used wherever a Type AC or Type A device is specified, as they provide the same functionality as these types and more.

 

TYPE of RCCB
TYPE AC Current 50Hz AC Current 50Hz To 1KHZ Pulsating Current with DC Component Multi Frequency Current Generated By 1Phase Inverter Multi Frequency Current Generated By 3Phase Inverter
AC √ – – – –
A √ – √ – –
F √ – √ √ –
B √ √ √ √ √
AS √ – √ – –
BS √ √ √ √ √

 

Sensitivity of RCCB
RCCBs Application
30 mA personal protection domestic installation / direct contact
100 mA limited personal protection / indirect contact
300 mA building / fire protection

 

MCB Enclosure Size
MCB Rating (A) Min. Enclosure Size
Height Width Depth
100A 370mm 216mm 72mm
125A 310mm 180mm 83mm
225A 370mm 217mm 72mm
250A 380mm 195mm 83.5mm
300A to 400A 506mm 381mm 153mm
600A to 800A 520mm 420mm 200mm
1000A to 1200A 704mm 554mm 173mm
1600A to 3000A 1016mm 608mm 615mm

 

Switch Gear Protection
Switch Gear Protection Isolation Control
Over Load Short Circuit
Fuse YES YES NO NO
Switch NO NO YES YES
Circuit Breaker YES YES YES YES
Contactor NO NO NO YES
Disconnector NO NO YES NO

 

Type of Faults
Types of Fault Reason Consequences  Protective Device to be used
Overload When Equipment tries to run beyond its rated capacity, or there is a fault in the equipment E.g. When you keep a heater on without any water in it. It can lead to reduction in life of equipment, Failure of insulation and hence damaging the equipment. MCB / RCBO
Short Circuit Insulation Failure, Shorting of the Phase to Phase or Phase and Neutral Wires. High Inrush Current, causing permanent damage to equipment and may lead to a Fire. MCB
Earth Fault Short circuit between Phase and Earth Conductor. Can result in Fire due to sparking. RCBO / RCCB
Earth Leakage Human Body Touching Live Wires. Insulation failure RCBO / RCCB
Over Voltage Opening of Neutral Connection increase in Phase To Phase Voltage of 440V, Surge through Lighting or transients, Over voltage from Utility. Damage to sensitive Electronic Equipment. OV protection Device
Under Voltage Drop in supply voltage, starting of heavy loads Damage of Equipment, Flickering of Lights. UV relays

 

 MCB Type (BS EN 60898-2)
Trip Type instantaneous
Trip (< 0.1 s)		 Load Type Typical Load
B 3 to 5 In (AC) Resistive Heaters, showers, cookers, socket outlets.
4 to 7 In (DC)
C 5 to 10 In (AC) Inductive Motors, general lighting circuits, power supplies.
7 to 15 In (DC)
D 10 to 20 In High Inductive Transformers, motors, discharge lighting circuits, computers

 

Relays for Transformer 
Capacity of Transformer Relays on HV Side Relays on LV Side Common Relays
Generator Transformer 3 Nos Non-Directional O/L Relay – – Differential Relay or
1 no Non-Directional E/L Relay Overall differential Relay
and/or standby E/F + REF Relay Over flux Relay
Buchholz Relay
OLTC Buchholz Relay
PRV Relay
OT Trip Relay
WT Trip Relay
220 /6.6KV Station Transformer 3 Nos Non-Directional O/L Relay 3 Nos Non-Directional O/L Relay Differential Relay
1 no Non-Directional E/L Relay Over flux Relay
and/or standby E/F + REF Relay Buchholz Relay
OLTC Buchholz Relay
PRV Relay
OT Trip Relay
WT Trip Relay
132/33/11KV up to 8 MVA 3 Nos O/L Relay 2 Nos O/L Relays Buchholz Relay
1 no E/L Relay 1 no E/L Relay OLTC Buchholz Relay
PRV Relay
OT Trip Relay
WT Trip Relay
132/33/11KV up to 8 MVA to 31.5 MVA 3 Nos O/L Relay 3 Nos O/L Relay Differential Relay
1 no Directional E/L Relay 1 no E/L Relay Buchholz Relay
OLTC Buchholz Relay
PRV Relay
OT Trip Relay
WT Trip Relay
132/33KV, 31.5 MVA & above 3 Nos O/L Relay 3 Nos O/L Relay Differential Relay
1 no Directional E/L Relay 1 no E/L Relay Over flux Relay
Buchholz Relay
OLTC Buchholz Relay
PRV Relay
OT Trip Relay
WT Trip Relay
220/33 KV, 31.5MVA & 50MVA , 220/132KV, 100 MVA 3 No O/L Relay 3 Nos O/L Relay Differential Relay
1 no Directional E/L Relay 1 no Directional E/L Relay Over flux Relay
Buchholz Relay
OLTC Buchholz Relay
PRV Relay
OT Trip Relay
WT Trip Relay
400/220KV 315MVA 3 Nos Directional O/L Relay 3 Nos Directional O/L Relay Differential Relay
1 no Directional E/L relay. 1 no Directional E/L relay. Over flux Relay
Restricted E/F relay Restricted E/F relay Buchholz Relay
3 Nos Directional O/L Relay for action OLTC Buchholz Relay
PRV Relay
OT Trip Relay
WT Trip Relay
Over Load (Alarm) Relay

 

Relays for Transmission & Distribution Lines Protection
Lines to be protected Relays to be used
400 KV Transmission Line Main-I: Non switched or Numerical Distance Scheme
Main-II: Non switched or Numerical Distance Scheme
220 KV Transmission Line Main-I : Non switched distance scheme (Fed from Bus PTs)
Main-II: Switched distance scheme (Fed from line CVTs)
With a changeover facility from bus PT to line CVT and vice-versa.
132 KV Transmission Line Main Protection : Switched distance scheme (fed from bus PT).
Backup Protection: 3 Nos. directional IDMT O/L Relays and
1 No. Directional IDMT E/L relay.
33 KV lines Transmission Line Non-directional IDMT 3 O/L and 1 E/L relays.
11 KV lines Transmission Line Non-directional IDMT 2 O/L and 1 E/L relays.

 

Selection Chart for 3Ph Induction Motor
Motor Rating,415V,3Ph Full Load Current (A) CONTACTOR (A) OVER LOAD RELAY (A) BACK UP FUSE (A) Cable Size
DOL Starter STAR-DELTA Starter
HP KW DOL STAR-DELTA DOL STAR-DELTA Alu. Cu. Alu. Cu.
0.75 0.52 1.6 16 1.0 To 1.6 4 1.5 1.5
1 0.75 2 16 1.6 To 2.5 6 1.5 1.5
2 1.5 3.5 16 3.0 To 4.5 10 1.5 1.5
3 2.2 5 16 4.5 To 7.0 10 1.5 1.5
5 3.7 7.5 16 6.5 To 10 16 1.5 1.5
7.5 5.5 11 16 16 10 To 15 4.5 To 7.0 16 2.5 1.5 2.5 1.5
10 7.5 14 16 16 13 To 20 6.5 To 10 20 2.5 2.5 2.5 2.5
12.5 9.3 18 25 16 13 To 20 10 To 15 25 4 2.5 4 2.5
15 11 21 25 16 15 To 22 13 To 20 25 6 4 6 4
20 15 28 32 18 24 To 30 13 To 20 32 10 6 10 6
25 18.5 35 40 25 25 To 30 15 To 22 50 16 10 16 10
30 22.5 40 50 25 32 To 50 24 To 30 50 16 16 16 16
35 26 47 70 32 32 To 50 25 To 30 63 25 16 25 16
50 37 66 70 40 57 To 70 32 To 50 80 35 25 35 25
60 45 80 95 50 70 To 105 32 To 50 100 50 35 50 35
75 55 100 125 70 100 To 150 40 To 57 100 70 50 70 50
90 67.5 120 140 70 100 To 150 57 To 70 160 95 70 95 70
100 75 135 140 95 100 To 150 70 To 105 160 95 70 95 70
125 90 165 125 70 To 105 160 150 95
150 110 200 125 100 To 150 200 185 150

 

MCB Selection Chart For Motor Protection
Kw HP 1Phase 230V DOL
Starting		 3Phase 400V DOL
Starting		 3 Phase 400V Star Delta
Full Load Current MCB Selection Full Load Current MCB Selection Full Load Current MCB Selection MCB Selection
0.18 0.24 2.8 10 0.9 2  —  —  —
0.25 0.34 3.2 10 1.2 2  —  —  —
0.37 0.5 3.5 10 1.2 2  —  —  —
0.55 0.74 4.8 16 1.8 3  —  —  —
0.75 1.01 6.2 20 2 3  —  —  —
1.1 1.47 8.7 25 2.6 6  —  —  —
1.5 2.01 11.8 32 3.5 10  —  —  —
2.2 2.95 17.5 50 4.4 10  —  —  —
3 4.02 20 63 6.3 16 6.3 16 10
3.75 5.03 24 80 8.2 20 8.2 20 10
5.5 7.37 26 80 11.2 25 11.2 32 16
7.5 10.05 47 125 14.4 40 14.4 40 25
10 13.4  —  — 21 50 21 50 32
15 20.11  — — 27 100 27 63 40
18.5 24.8  —  — 32 125 32  — 50
22 29.49  —  — 38 125 38 — 63
30 40.21  —  — 51 125 51  — 63

 

RELAY CODE (ANSI)
Code Type of Relay
1 Master Element
2 Time-delay Starting or Closing Relay
3 Checking or Interlocking Relay
4 Master Contactor
5 Stopping Device
6 Starting Circuit Breaker
7 Rate of Change Relay
8 Control Power Disconnecting Device
9 Reversing Device
10 Unit Sequence Switch
11 Multifunction Device
12 Over speed protection
13 Synchronous-Speed Device
14 Under speed Device
15 Speed or Frequency Matching Device
16 Data Communications Device
17 Shunting or Discharge Switch
18 Accelerating or Decelerating Device
19 Starting-to-Running Transition Contactor
20 Electrically-Operated Valve
21 Distance protection Relay
21G Ground Distance
21P Phase Distance
22 Equalizer circuit breaker
23 Temperature control device
24 Volts per hertz relay
25 Synchronizing or synchronism-check device
26 Apparatus thermal device
27 Under voltage relay
27P Phase Under voltage
27S DC under voltage relay
27TN Third Harmonic Neutral Under voltage
27TN/59N 100% Stator Earth Fault
27X Auxiliary Under voltage
27 AUX Under voltage Auxiliary Input
27/27X Bus/Line Under voltage
27/50 Accidental Generator Energization
28 Flame Detector
29 Isolating Contactor
30 Annunciator Relay
31 Separate Excitation Device
32 Directional Power Relay
32L Low Forward Power
32N Watt metric Zero-Sequence Directional
32P Directional Power
32R Reverse Power
33 Position Switch
34 Master Sequence Device
35 Brush-Operating or Slip-ring Short Circuiting Device
36 Polarity or Polarizing Voltage Device
37 Undercurrent or Under power Relay
37P Under power
38 Bearing Protective Device / Bearing Rtd
39 Mechanical Condition Monitor
40 Field Relay / Loss of Excitation
41 Field Circuit Breaker
42 Running Circuit Breaker
43 Manual Transfer or Selector Device
44 Unit Sequence Starting Relay
45 Atmospheric Condition Monitor
46 Reverse-Phase or Phase Balance Current Relay or Stator Current Unbalance
47 Phase-Sequence or Phase Balance Voltage Relay
48 Incomplete Sequence Relay / Blocked Rotor
49 Machine or Transformer Thermal Relay / Thermal Overload
49RTD RTD Biased Thermal Overload
50 Instantaneous Overcurrent Relay
50BF Breaker Failure
50DD Current Disturbance Detector
50EF End Fault Protection
50G Ground Instantaneous Overcurrent
50IG Isolated Ground Instantaneous Overcurrent
50LR Acceleration Time
50N Neutral Instantaneous Overcurrent
50NBF Neutral Instantaneous Breaker Failure
50P Phase Instantaneous Overcurrent
50SG Sensitive Ground Instantaneous Overcurrent
50SP Split Phase Instantaneous Current
50Q Negative Sequence Instantaneous Overcurrent
50/27 Accidental Energization
50/51 Instantaneous / Time-delay Overcurrent relay
50Ns/51Ns Sensitive earth-fault protection
50/74 Ct Trouble
50/87 Instantaneous Differential
51 Phase Inverse Time Overcurrent IDMT (Time delay phase overcurrent )
51G Ground Inverse Time Overcurrent
51LR AC inverse time overcurrent (locked rotor) protection relay
51N Neutral Inverse Time Overcurrent
51P Phase Time Overcurrent
51R Locked / Stalled Rotor
51V Voltage Restrained Time Overcurrent
51Q Negative Sequence Time Overcurrent
52 AC circuit breaker
52a AC circuit breaker position (contact open when circuit breaker open)
52b AC circuit breaker position (contact closed when circuit breaker open)
53 Exciter or Dc Generator Relay
54 Turning Gear Engaging Device
55 Power Factor Relay
56 Field Application Relay
57 Short-Circuiting or Grounding Device
58 Rectification Failure Relay
59 Overvoltage Relay
59B Bank Phase Overvoltage
59P Phase Overvoltage
59N Neutral Overvoltage
59NU Neutral Voltage Unbalance
59P Phase Overvoltage
59X Auxiliary Overvoltage
59Q Negative Sequence Overvoltage
60 Voltage or current balance relay
60 Voltage or Current Balance Relay
60N Neutral Current Unbalance
60P Phase Current Unbalance
61 Density Switch or Sensor
62 Time-Delay Stopping or Opening Relay
63 Pressure Switch Detector
64 Ground Protective Relay
64F Field Ground Protection
64R Rotor earth fault
64REF Restricted earth fault differential
64S Stator earth fault
64S Sub-harmonic Stator Ground Protection
64TN 100% Stator Ground
65 Governor
66 Notching or Jogging Device/Maximum Starting Rate/Starts Per Hour/Time Between Starts
67 AC Directional Overcurrent Relay
67G Ground Directional Overcurrent
67N Neutral Directional Overcurrent
67Ns Earth fault directional
67P Phase Directional Overcurrent
67SG Sensitive Ground Directional Overcurrent
67Q Negative Sequence Directional Overcurrent
68 Blocking Relay / Power Swing Blocking
69 Permissive Control Device
70 Rheostat
71 Liquid Switch
72 DC Circuit Breaker
73 Load-Resistor Contactor
74 Alarm Relay
75 Position Changing Mechanism
76 DC Overcurrent Relay
77 Telemetering Device
78 Phase Angle Measuring or Out-of-Step Protective Relay
78V Loss of Mains
79 AC Reclosing Relay / Auto Reclose
80 Liquid or Gas Flow Relay
81 Frequency Relay
81O Over Frequency
81R Rate-of-Change Frequency
81U Under Frequency
82 DC Reclosing Relay
83 Automatic Selective Control or Transfer Relay
84 Operating Mechanism
85 Pilot Communications, Carrier or Pilot-Wire Relay
86 Lock-Out Relay, Master Trip Relay
87 Differential Protective Relay
87B Bus Differential
87G Generator Differential
87GT Generator/Transformer Differential
87L Segregated Line Current Differential
87LG Ground Line Current Differential
87M Motor Differential
87O Overall Differential
87PC Phase Comparison
87RGF Restricted Ground Fault
87S Stator Differential
87S Percent Differential
87T Transformer Differential
87V Voltage Differential
88 Auxiliary Motor or Motor Generator
89 Line Switch
90 Regulating Device
91 Voltage Directional Relay
92 Voltage And Power Directional Relay
93 Field-Changing Contactor
94 Tripping or Trip-Free Relay
Abbreviation Code
AFD Arc Flash Detector
CLK Clock or Timing Source
CLP Cold Load Pickup
DDR Dynamic Disturbance Recorder
DFR Digital Fault Recorder
DME Disturbance Monitor Equipment
ENV Environmental data
HIZ High Impedance Fault Detector
HMI Human Machine Interface
HST Historian
LGC Scheme Logic
MET Substation Metering
PDC Phasor Data Concentrator
PMU Phasor Measurement Unit
PQM Power Quality Monitor
RIO Remote Input/output Device
RTD Resistance Temperature Detector
RTU Remote Terminal Unit/Data Concentrator
SER Sequence of Events Recorder
TCM Trip Circuit Monitor
LRSS  Local/Remote selector switch
VTFF  Vt Fuse Fail

Suffixes Description
_1 Positive-Sequence
_2 Negative-Sequence
A Alarm, Auxiliary Power
AC Alternating Current
AN Anode
B Bus, Battery, or Blower
BF Breaker Failure
BK Brake
BL Block (Valve)
BP Bypass
BT Bus Tie
BU Backup
C Capacitor, Condenser, Compensator, Carrier Current, Case or Compressor
CA Cathode
CH Check (Valve)
D Discharge (Valve)
DC Direct Current
DCB Directional Comparison Blocking
DCUB Directional Comparison Unblocking
DD Disturbance Detector
DUTT Direct Under reaching Transfer Trip
E Exciter
F Feeder, Field, Filament, Filter, or Fan
G Ground or Generator
GC Ground Check
H Heater or Housing
L Line or Logic
M Motor or Metering
MOC Mechanism Operated Contact
N Neutral or Network
O Over
P Phase or Pump
PC Phase Comparison
POTT  Pott: Permissive Overreaching Transfer Trip
PUTT Putt: Permissive Under reaching Transfer Trip
R Reactor, Rectifier, or Room
S Synchronizing, Secondary, Strainer, Sump, or Suction (Valve)
SOTF Switch On To Fault
T Transformer or Thyratron
TD Time Delay
TDC Time-Delay Closing Contact
TDDO Time Delayed Relay Coil Drop-Out
TDO Time-Delay Opening Contact
TDPU Time Delayed Relay Coil Pickup
THD Total Harmonic Distortion
TH Transformer (High-Voltage Side)
TL Transformer (Low-Voltage Side)
TM Telemeter
TT Transformer (Tertiary-Voltage Side)
U Under or Unit
X Auxiliary
Z Impedance

 

Harmonic Effects
Harmonic R Phase Y Phase B Phase Phase Rotation Sequence Harmonic Effect
Rotation Rotation Rotation
Fundamental 0° 120° 240° R-Y-B  
3th 3×0°=0° 3×120°=360°=0° 3×240°=720°=0° No Rotation          (In Phase) Adds Voltages or Currents in Neutral Wire causing Heating
9th 9×0°=0° 9×120°=1080°=0° 9×240°=2160°=0°
15th 15×0°=0° 15×120°=1800°=0° 15×240°=3600°=0°
21th 21×0°=0° 21×120°=2520°=0° 21×240°=5040°=0°
5th 5×0°=0° 5×120°=600°=(600-720)=(-120°) 5×240°=1200°=(1200-2400)=(-240°) Rotate Against Fundamental (-) (B-Y-R) Motor Torque Problems
11th 11×0°=0° 11×120°=1320°=(1320-1400)=(-120°) 11×240°=2640°=(2880-2640)=(-240°)
17th 17×0°=0° 17×120°=2040°=(2040-2160)=(-120°) 17×240°=4080°=(4320-4080)=(-240°)
23th 23×0°=0° 23×120°=2760°=(2760-2880)=(-120°) 23×240°=5520°=(5760-5520)=(-240°)
7th 7×0°=0° 7×120°=840°=(840-720)=(+120°) 7×240°=1680°=(1680-1440)=(+240°) Rotate with Fundamental (+) (R-Y-B) Excessive Heating Effect
13th 13×0°=0° 13×120°=1560°=(1560-1440)=(+120°) 13×240°=3120°=(3120-2880)=(+240°)
19th 19×0°=0° 19×120°=2280°=(2280-2160)=(+120°) 19×240°=4560°=(4560-4320)=(+240°)
25th 25×0°=0° 25×120°=3000°=(3000-2880)=(+120°) 25×240°=6000°=(6000-5760)=(+240°)

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7 Responses to MCB / MCCB / ELCB Quick Reference (Part-2)

  1. Mani Kandan's avatar Mani Kandan says:
    November 17, 2018 at 2:28 am

    very usefull,thank you sir,thanks lot

    p.manikandan

    On Fri, 16 Nov 2018 at 22:55, Electrical Notes & Articles wrote:

    > Jignesh.Parmar posted: ” Selection of MCB MCB curve Type of Load > Residential Commercial B curve Resistive Loads Incandescent lights > Incandescent lights Geyser Boilers Heater Heaters Fan blower heaters Oil > radiator heaters Slight Inductive Loads Floresce” >

    Reply
  2. rohit singh's avatar rohit singh says:
    November 17, 2018 at 4:07 am

    Thank you so much for this valuable information…very good work , keep going.Thanks & regardsRohit SinghFrom: Electrical Notes & Articles <comment-reply@wordpress.com>Sent: Fri, 16 Nov 2018 22:55:45To: rohitsingh.1064@rediffmail.comSubject: [New post] Electrical Thumb Rules-(Part-15)WordPress.com Jignesh.Parmar posted: "  Selection of MCB MCB curve Type of Load Residential Commercial B curve Resistive Loads Incandescent lights Incandescent lights Geyser  Boilers  Heater  Heaters Fan blower heaters Oil radiator heaters Slight Inductive Loads Floresce"

    Reply
  3. MAHESH JADHAV's avatar MAHESH JADHAV says:
    November 17, 2018 at 2:22 pm

    IS it advisable to operate automatic power factor panel run on DG power source?

    ________________________________

    Reply
  4. Vivekanand Pandey's avatar Vivekanand Pandey says:
    November 17, 2018 at 5:06 pm

    Thanks Sir
    For most important notes

    Reply
  5. Arabinda Chakraborty's avatar Arabinda Chakraborty says:
    November 18, 2018 at 4:17 am

    Excellent.Very much appreciated . Regards Arabinda Chakraborty

    On Fri, Nov 16, 2018 at 10:55 PM Electrical Notes & Articles wrote:

    > Jignesh.Parmar posted: ” Selection of MCB MCB curve Type of Load > Residential Commercial B curve Resistive Loads Incandescent lights > Incandescent lights Geyser Boilers Heater Heaters Fan blower heaters Oil > radiator heaters Slight Inductive Loads Floresce” >

    Reply
  6. Arabinda Chakraborty's avatar Arabinda Chakraborty says:
    November 18, 2018 at 4:25 am

    CAn you please highlight on Life cycle of electrical switchgears ?? Regards Arabinda Chakraborty

    On Fri, Nov 16, 2018 at 10:55 PM Electrical Notes & Articles wrote:

    > Jignesh.Parmar posted: ” Selection of MCB MCB curve Type of Load > Residential Commercial B curve Resistive Loads Incandescent lights > Incandescent lights Geyser Boilers Heater Heaters Fan blower heaters Oil > radiator heaters Slight Inductive Loads Floresce” >

    Reply
  7. Hulagappa kuri's avatar Hulagappa kuri says:
    November 22, 2018 at 1:14 pm

    Super sir thanks for the information sir

    Reply

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