How to select MCB / MCCB (Part:2)
November 2, 2016 17 Comments
(C) Application Type:
(9) Utilization category / Characteristic (B, C, D, K, Z curve):
- Characteristic of Trip curves of MCCB tell about the trip current rating of MCCB.
- MCB will trip instantaneously according to their Tripping Characteristic at 0.1 sec.
- There are various type of MCCB
- Type B MCCB
- Type C MCCB
- Type D MCCB
- Type K MCCB
- Type Z MCCB
Type B MCCB:
- Operating Current: This type of MCB trips between 3 and 5 times rated current (In).
- Operating Time:04 To 13 Sec
- For example a 10A device will trip at 30-50A.
- Application: Domestic applications or light commercial applications where connected loads are primarily lighting fixtures, domestic appliances with mainly restive elements.
- Suitable for: Restive Load application (Lighting , Small Motor)
- Surge Current: The surge current level is relatively low.
- Installation at: At Sub feeder of Distribution Board.
Type C MCCB:
- Operating Current: This type of MCB trips between 5 and 10 times full load current.
- Operating Time:04 To 5 Sec
- Application: commercial or industrial type of applications, fluorescent lighting, motors etc where there could be chances of higher values of short circuit currents in the circuit.
- Suitable for: Inductive Load application (Pumps, Motor, fluorescent lighting.)
- Surge Current: The surge current level is relatively moderate level.
- Installation at: At incoming / Outgoing of Distribution Board.
Type D MCCB:
- Operating Current: This type of MCB trips between 10 and 20 times full load current.
- Operating Time:04 To 3 Sec
- Application: specialty industrial / commercial uses (Transformers or X-ray machines, large winding motors, discharge lighting, large battery charging). Where current inrush can be very high.
- Suitable for: Inductive- Capacitive Load application (Pumps, Motor)
- Surge Current: The surge current level is relatively High
- Installation at: At incoming of Distribution Board / Panels.
Type K MCCB:
- Operating Current: This type of MCB trips between 8 and 12 times full load current.
- Operating Time:04 To 5 Sec
- Application: Suitable for inductive and motor loads with high inrush currents.
- Surge Current: The surge current level is relatively High
- Installation at: At incoming of Distribution Board / Panels.
Type Z MCCB:
- Operating Current: This type of MCB trips between 2 and 3 times full load current.
- Operating Time:04 To 5 Sec
- Application: These types of MCBs are highly sensitive to short circuit and are used for protection of highly sensitive devices such as semiconductor devices.
- Surge Current: The surge current level is relatively too low
- Installation at: At Sub feeder of Distribution Board for IT equipment.
(D) Accessories:
(1) Rotary Handle:
- It is used to extend ON/OFF handle of MCCB when Panel Door is closed.
- It is also used to indicate ON/OFF or Trip Position
(2) Shunt Trip:
- Used for Remote Tripping
(3) Alarm contact:
- It gives Tripping Indication when MCCB Trip.
- It does not give when MCCB is in normal condition (either ON or OFF)
(4) Auxiliary contact:
- It used for remote signaling and control purpose.
- It is also give ON/OFF indication of MCCB at remote location.
(5) Under Voltage Tripping:
- It used to trip MCCB in under voltage condition (70 to 35% of rated Voltage).
(6) Mechanical Interlocking:
- It used to mechanical interlock of two MCCB on the same Panel.
(7) Manual / Auto:
- MCCB may have provision for Auto /Manual operation.
- An “auto/manual” switch in front of Panel.
- When set to the “Manual” position, lock out electrical control and when set to “auto”, lock out the manual control; remote indication
(8) Motorized operation:
- MCCB may have option for manual operation or with a motor mechanism for electrically controlled
JIGNESH PARMAR
Hi parmar,
I need ur guidance to get a HT power supply for my site,
MD is 1650 KVA and what are procedures I have to follow in uttar Pradesh Electricity board.
Sir can you provide me your email id?
Hi sir thanks for information. And I want all safe values of electrical apparatus for example cable insulation values, transformer insulation values,earthing values, motor insulation values, insulators, continuity values,IE rules, with numbers. This information I require, thank you sir, with regards On 02-Nov-2016 6:18 PM, “Electrical Notes & Articles” wrote:
> Jignesh.Parmar posted: “(C) Application Type: (9) Utilization category / > Characteristic (B, C, D, K, Z curve): Characteristic of Trip curves of MCCB > tell about the trip current rating of MCCB. MCB will trip instantaneously > according to their Tripping Characteristic at 0.1 sec” >
ThanksPlease categorize the difference and their application of RCCBThanksRegardsSrikanth
Sent from my Samsung device
Please categorize RCCB and their applications
Thanks
Regards
Srikanth
Great solution….
Jignesh.Parmar
thanks for this info
(I use your site quite for all sorts of info that is not readily available elsewhere
so please keep up the good work
Regards
Tony Zonneveld | Distribution Technology Specialist
GOOD VERY USEFUL
On Wed, Nov 2, 2016 at 6:17 PM, Electrical Notes & Articles wrote:
> Jignesh.Parmar posted: “(C) Application Type: (9) Utilization category / > Characteristic (B, C, D, K, Z curve): Characteristic of Trip curves of MCCB > tell about the trip current rating of MCCB. MCB will trip instantaneously > according to their Tripping Characteristic at 0.1 sec” >
sir,how we conduct generator testing?
sir,how we conduct generator testing
Thank you sir.
Hi sir please clear me one doubt, how the fuel consumption calculated, on dg set
very educative
Describe the precautions necessary to deal with each of the following issues when carrying out an oil change on an 11 kv/400 v transformer.
Dear sir,
those articles are very helpful for all electrical professional specially freshers .
Thank you. It’s very helpful for us.
G’ day,
I am working on designing protection devices for my research work and I am struggling to model the thermal part for the low voltage circuit breakers based on IEC standards.
Based on the standards, the time current curve for types B, C and D are as mentioned on the attached figure. I could not find the proper formula which represents the thermal characteristic for these types. Please, assist on this matter.
Thank you for your cooperation in advance.