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When should i use MCCB and MCB Breakers?

02/20/2009 1:12 AM

When should i use Molded Case Circuit Breakers and Mini Circuit Breakers?

what is the smallest Ampere rating of a breaker should i use for a motor without tripping it during starting and should i use MCCB or MCB, Pls. help

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Commentator
India - Member - PROFESSIONAL Engineering Fields - Power Engineering - electrical planning - designing

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#1

Re: When should i use MCCB and MCB Breakers?

02/20/2009 4:13 AM

Dear Friend,

Trying to answer your question as :-

When should i use Molded Case Circuit Breakers and Mini Circuit Breakers?

* First of all MCB is Miniature Circuit Breaker , since it is miniature it has limitation for S C and Amp Rating Both.

# MCB are available as Singe module and used for :-

Number of Pole :- 1,2,3,4 - 1+ N , & 3 + N

# Usually Current range for A.C., 50-60 HZ ., are from 0.5 Amp - 63 Amp.

Also available 80A, 100A, and 125 Amp.

# SC are limited 10 KA

# Applications are as :- Industrial , Commercial and Residential application.

# Tripping Curve

B Resistive and lighting load

c Motor Load

D Highly inductive load.

* MCCB :- Moulded Case Circuit Breaker

# MCCB are available as Singe module and used for :-

Number of Pole :- 3 pole , & 4 Pole

# Usually Current range for A.C., 50-60 HZ ., are from

3.2 /6.3/12.5/25/50/100/125/ 160 Amp. - SC 25/35/65 KA

200 250 Amp. - SC 25/35/65 KA

400 630/800 Amp - SC 50 KA

# Protection release :-

Static Trip :- Continuous adjustable overload protection range 50 to 100 % of the rated current

Earth fault protection can be add on with adjustable earth fault pick up setting 15 to 80 % of he current

# Micro processor Based release :-

Over load rated current 0.4 - 1.0 in steps of o.1 of ln trip time at 600 % Ir(sec) 0.2.0.5,1, 1.5 , 2 ,3

Short Circuit :-2 - 10 in steps of 1 lr , short time delay (sec) 0.02.0.05,0.1, 0.2 ,0.3

Instantaneous pick up ;- 2 - 10 in steps of 1 ln Ground fault pick up Disable, 0.2 - 0.8 in steps of 0.1 of in

Ground fault delay (sec) - 0.1 -=to 0.4 in steps of 0.1

This are available with communiction port RS 485 and protocol MODBUS,RU

THE ABOVE INFORMATION CAN VERY WITH DIFFRENET MANUFACTURER

HOPE YOUR QUERRY HAS BEEN TRIED TO ANSWER WITH IMMEDIATE AVAILABLE INFORMATION

NIRANJAN A SHATSRI

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Guru
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#2
In reply to #1

Re: When should i use MCCB and MCB Breakers?

02/20/2009 8:52 AM

Hi Niranjan,

You have explained very well in a language which a technical person can understand . Now MCCB is available up to 1600 amps rating also. Due to its compactness they are replacing ACBs even for high capacity switching. There are many threads in CR4 on the same subject.

Good Answer.

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#3
In reply to #1

Re: When should i use MCCB and MCB Breakers?

02/21/2009 11:28 PM

GA

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#4

Re: When should i use MCCB and MCB Breakers?

03/05/2009 11:07 AM

Let me add - on

In choosing MCCBs VS MCBs, its not just the rating, its also about discrimination.


well discriminated breaker configuration will ensure that 1 branch trips without affecting another branch, thus ensuring continutity of power supply

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Commentator
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#5
In reply to #4

Re: When should i use MCCB and MCB Breakers?

03/06/2009 3:43 AM

Let me add - on

In choosing MCCBs VS MCBs, its not just the rating, its also about discrimination.


well discriminated breaker configuration will ensure that 1 branch trips without affecting another branch, thus ensuring continuity of power supply

DEAR FRIEND,

WHAT DISCRIMINATION R U REFERING ?

I THINK YOU ARE REFEERINGABOUT DISCRIMINATING THE FAULT .

WHICH BRANCH ?

ARE YOU TALKING ABOUT VARIOUS FEEDERS CONNECTED TO VARIOUS LOAD ?

THE DISCRIMINATIONS ARE CO ORDINATED WITH SELECTION OF RATING FOR S.C./ O.C/ E.F.C ETC., WITH PROTECTIVE RELAYS. AND RATING OF FEEDER RECEIVING OF POWER FOR DISTIBUTION TO GROUP OF FEEDER WITH SAY X - AMP , THAN THE UP STERAM FEEDER RATING ARE WITH > THAN THAT RATINGS AND SETTINGS OF PROTECTION ARE BEING CO ORDINATED ACCORDINGLY , THE OUT GOING FEEDERS RATINGS ARE < THAN THE FEEDER RECEIVING POWER AND CONNECTED AS IN COMING TO THE BUS.

THE SAME WAY S.C /FAULT CURRENT RATINGS SHOULD BE RATED < TOWARADS MAIN IN COMING FEEDER TO OUT GOING FEEDERS AS PER S.C OF RESPECTIVE FEEDER LOAD.

ANY QUERRY R APPRECIATED AND CAN BE DISCUSSED BY CASE STUDY IF YOU HAVE SPECIFIC DISTRIBUTION NET WROK TO DESIGN.

REGARDS N THANKS.

nascon

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