BIJLIBEE PROTECTION TOOL

MCB Size Calculator

Load, derating, inrush, cable capacity aur fault level ke saath preliminary breaker selection karein.

Safety: MCB shock protection ka replacement nahi hai. Final breaker, curve, cable, RCD/RCBO aur fault coordination qualified electrician/engineer se verify karayein.

Load & Protection Details

Load Input TypeKilowatt (kW)Ampere (A)Kilovolt-Ampere (kVA)Horsepower (HP)

SupplySingle Phase ACThree Phase ACDC Supply

Load ValueElectrical input kW

Voltage

Power Factor

EfficiencyUsed for HP mode

Continuous Load FactorPercent

Ambient DeratingNormal / manufacturer referenceWarm enclosure 0.95Hot enclosure 0.90Very hot enclosure 0.80

Grouping DeratingSingle breaker / ventilatedModerate grouping 0.95Dense grouping 0.90Severe grouping 0.80

Load Type / InrushLighting / electronics (2x)Heater / resistive (1x)General motor / pump (4x)Heavy motor / transformer (7x)Very high inrush (12x)

Cable AmpacityA; zero means unknown

Prospective Fault CurrentkA at installation point

Daily Usage

Billing Days

Electricity RateRupees per unit

Values check karein. Standard rating, cable ampacity ya breaking-capacity condition satisfy nahi ho rahi.

PRELIMINARY BREAKER SELECTION

20 A C-Curve MCB

1P+N / 6 kA breaking capacity

Cable coordination check passed

Running Current14.49 A

Adjusted Required Rating18.11 A

Estimated Inrush28.99 A

Rating Utilisation72.47%

Suggested Trip Curve	C - General purpose/inrush
Magnetic Pickup Band	5x to 10x In
Minimum Breaking Capacity	6 kA
Cable Ampacity Check	20 A MCB <= 25 A cable
Protection Type Reminder	RCD/RCBO selection required separately
Estimated Active Load	3.00 kW
Monthly Units / Cost	720.00 / ₹5,760.00
Yearly Units / Cost	8,760.00 / ₹70,080.00

MCB size kaise select hota hai?

Breaker ka rated current load current se kam nahi aur protected cable ki corrected capacity se zyada nahi hona chahiye. Breaking capacity installation point ke prospective short-circuit current ke barabar ya zyada honi chahiye. Motor aur transformer inrush ke liye suitable trip curve aur manufacturer coordination zaroori hai. Breaker ke sath sahi wire choose karne ke liye hamara Wire Size Calculator dekhein.

B, C aur D curve ka basic use

• B curve: low-inrush resistive ya lighting loads ke liye preliminary option.
• C curve: moderate inrush wale general circuits aur small motors.
• D curve: high inrush motors/transformers; fault-loop aur disconnection checks critical hain.

Pure ghar ke distribution panel ka total load aur breaker sizing nikalne ke liye Home Load Calculator use karein, aur bijli bachat ke liye Ghar Ka Bijli Bill Kam Karne Ke Tarike guide padhein.

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FAQs

MCB aur RCCB/RCBO mein kya difference hai?

MCB overload aur short circuit protection deta hai. Residual-current shock/leakage protection ke liye suitable RCD/RCCB/RCBO separately chahiye.

Kya load ka 125% lekar MCB choose karna hamesha sahi hai?

Nahi. Continuous-load rules, equipment instructions, standard, conductor capacity aur breaker temperature conditions ke hisaab se factor badal sakta hai.

Breaking capacity kya hoti hai?

Breaker safely kitna prospective short-circuit current interrupt kar sakta hai. Iski rating calculated fault current se kam nahi honi chahiye.

Kya calculator ka result direct install kar sakte hain?

Nahi. Cable, earth-fault loop, selectivity, disconnection time, RCD type aur manufacturer tables professional verify kare.

Disclaimer: Yeh preliminary estimate hai. Final MCB/MCCB, curve, poles, breaking capacity, RCD/RCBO aur cable coordination qualified electrical professional se approve karayein.

WRITTEN & REVIEWED BY

Satyam Kumar Yadav

Founder and Creator of BijliBee. Satyam electricity calculations, practical energy-saving tools aur simple Hinglish guides ko aam users ke liye aasan banane par kaam karte hain.