MCB FAQs
Safety of end users is our first concern — for the electrification of your house, office, factory and more. Keep these points in mind when specifying and installing MCBs.
Points to remember
01Number of Circuits
Plan enough circuits to handle the load without overloading. Install individual MCBs for high-power equipment so a surge or short circuit stays contained to one circuit.
02Current Carrying Capacity
A conductor's ampacity depends on size, material, insulation and ambient temperature. Size conductors to safely carry the expected load without overheating.
03Quality of Material
An installation is only as safe as its components. Use high-quality wires and MCB boxes — inferior materials risk overheating, melting and fire.
04Fool-Proof Safety
Combine MCBs, RCCBs, MCCBs, isolators and changeover switches. RCCBs catch leakage current; MCBs cut overload and short-circuit faults — together they cover the full range of electrical faults.
05Frequently Tripping MCB
Repeated tripping usually means overload, a short circuit from damaged wiring, earth leakage, or a faulty breaker. Have a certified electrician diagnose the cause.
06Wire Connections
Secure connections with lugs or thimbles. Loose joints spark and can cause equipment failure or fire; proper terminations keep the system safe and efficient.
07MCB Category to Use
Use category 'B' MCBs for resistive loads (ovens, geysers, heaters) and category 'C' for inductive loads (motors, ACs, refrigerators). The wrong category causes nuisance tripping or fails to trip.
08Protecting Electrical Installations
Shield panels and distribution boards from dust and moisture using quality enclosures, seals and MCCBs. Proper grounding, insulation and maintenance keep installations safe long-term.
09Earthing Electrical Equipment
Proper earthing channels fault current safely away, preventing shock and fire. Always have grounding carried out by qualified, licensed professionals.
MCB selection criteria
When choosing a Miniature Circuit Breaker (MCB), several factors should be considered, including rating, breaking capacity, trip characteristics, number of poles, installation style, and brand/quality. The maximum current rating of the circuit and the breaking capacity of the MCB should be the same. Additionally, the breaking capacity should be greater than the maximum fault current that may occur. The number of phases in the circuit should be considered when determining the MCB's number of poles. The MCB should be selected based on how well it can endure the installation environment. The table below gives indicative MCB ratings for common single-phase appliances at 240V.
| Appliances | Capacity / Watt (Load) at 240V single phase | MCB Rating |
|---|---|---|
| Air Conditioner | 1.0 Ton | 10A |
| Air Conditioner | 1.5 Ton | 16A |
| Air Conditioner | 2.0 Ton | 20A |
| Cooking Range | With oven cum griller — 4500 Watts | 25A |
| Cooking Range | With oven cum griller — 1750 Watts | 10A |
| Cooking Range | Oven only — 750 Watts | 6A |
| Cooking Range | Hot plate only — 2000 Watts | 10A |
| Room Heater | 1000 Watts | 6A |
| Room Heater | 2000 Watts | 6A |
| Geyser (Storage / Instantaneous) | 1000 Watts | 10A |
| Geyser (Storage / Instantaneous) | 2000 Watts | 10A |
| Geyser (Storage / Instantaneous) | 3000 Watts | 16A |
| Geyser (Storage / Instantaneous) | 6000 Watts | 32A |
| Washing Machine (Automatic) | 1300 Watts | 6A |
| LCD & LED TV | 750 Watts | 6A |
| Photo Copier | 1500 Watts | 6A |
| Electric Kettle | 1500 Watts | 10A |
| Mixer Grinder | 1000 Watts | 6A |
| Toaster | 1200 Watts | 6A |
| Electric Iron | 1250 Watts | 6A |
Frequently asked questions
A Miniature Circuit Breaker is an automatic switch that protects a circuit from overload and short-circuit faults by cutting off the supply.
An MCB is resettable and trips precisely on a fault; a fuse melts and must be replaced. MCBs are safer and more convenient.
Common causes are overload, a short circuit, earth leakage, or a faulty breaker. A certified electrician should diagnose the exact cause.
The rating is the current the MCB can carry continuously; above it, the breaker trips to protect the circuit.
Use 'B' for resistive loads, 'C' for inductive loads, and 'D' for high-inrush equipment.
MCBs protect against overload and short circuit. For shock protection against earth leakage, use an RCCB alongside the MCB.
Yes. Axiom MCBs are manufactured to IS/IEC 60898-1:2015 and BIS specifications by an ISO 9001:2015 certified company.
Axiom MCBs use standard DIN-rail mounting and fit standard distribution boards, including Axiom's own DBs.
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