Golgappa.net | Golgappa.org | BagIndia.net | BodyIndia.Com | CabIndia.net | CarsBikes.net | CarsBikes.org | CashIndia.net | ConsumerIndia.net | CookingIndia.net | DataIndia.net | DealIndia.net | EmailIndia.net | FirstTablet.com | FirstTourist.com | ForsaleIndia.net | IndiaBody.Com | IndiaCab.net | IndiaCash.net | IndiaModel.net | KidForum.net | OfficeIndia.net | PaysIndia.com | RestaurantIndia.net | RestaurantsIndia.net | SaleForum.net | SellForum.net | SoldIndia.com | StarIndia.net | TomatoCab.com | TomatoCabs.com | TownIndia.com
Interested to Buy Any Domain ? << Click Here >> for more details...

how to select a circuit breaker?

Answer Posted / majid amoudi

direct technical answer:-
suppose if d interviewver asks u
"for 11kva transformer what size of d ckt breaker shud b used"
answer-
11kva= 11,000va

11,000 divided by 220v(depending on various countries voltage rating)=50A
50A is d current passing thru d ckt...according to NEC(national electrical code) current shud be 125%...
so, 50* 1.25=62.5A
d breaker will trip if d current passes more dan 62.5A & d ckt breaker size shud be selected 4 times d nominal ckt breaker current i.e 62.5*4=250A.
so..a MCCB(moulded case circuit breaker) of 250A shud be used for 11kva T/F.

Is This Answer Correct ?    2 Yes 1 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

how we can set the IDMT relay.

2218


HOW TO CALCULATE AMPs OF CURRENT TRANSFORMER IN HT Panel

2398


WHAT KIND OF LIGHTENING PROTECTION SCHEMS CAN BE ADOPTED FOR THE FLAT ROOF OF BIG DIMENSION.

2128


Ceiling Fan and Storage type water heater. Discuss

1968


What are the site acceptance tests for power cables, DG Sets, LT panels & 30kVA UPS ?

2398


In parallel operation time both NGR’s close or not close if both close what will happen

3734


Why 11kv to be generated in generation station

1673


Explain Random and Deterministic signals?

1810


Currently what is the highest capacity (MVA) of SPPg generator available in the market?

1817


Why it need to form a capcitor when it not been in use from three or two year. Plz describe it technically.

1939


A logic circuit that provides a HIGH output if one input or the other input, but not both, is HIGH, is a(n)?

1243


how a resistor resists to flow the current?how an inductor oppses the sudden change in current?how a capacitor opposes a DC voltage.

2768


How to work E.L.C.B and how to connect in circuit.

2018


What is the unit audit? if our Max demand is something and we found much more unit then how to improve our max demand?

1956


I HAVE A INCOMING 100A MCCB TPN 25KA, CABLE LENGHT OF 80M 70MM CABLE SIZE FROM MAIN SUBBOARD TO NEW DB.BASE ON THE FAULT LEVEL SETTING OF 45KA.I WOULD LIKE TO FIND OUT 25KA ENOUGH KA. APPRECIATE IF SOMEBODY CAN ASSIST ME WITH FORMULA FOR THIS. FRM: JEFF

4037