Electrical protection devices are essential in every Malaysian home. Yet many people remain confused between MCB and RCCB—which one prevents fire, which one protects human life, and which one should be installed in your DB (Distribution Board).
This guide explains both devices in a clear, practical way, based on real electrical standards and Malaysian installation practices.
What is an MCB? (Miniature Circuit Breaker)
An MCB protects your home from overload and short circuits.
How it protects your home
When too many appliances run on one circuit
When an appliance draws abnormal current
When a wire melts or touches another wire
When a device is faulty and sparks internally
The MCB senses excessive current and instantly trips to prevent overheating and fire.
Common appliances that trigger MCB
Iron
Water heater
Aircond
Microwave
Kettle
Washing machine
In simple words:
MCB protects your house and wiring from burning.
What is an RCCB? (Residual Current Circuit Breaker)
An RCCB protects human life from electric shock by detecting current leakage.
How it protects you
If electricity escapes from the system—through water, a metal body, or a human body—the RCCB detects the imbalance and trips within milliseconds, cutting the power supply.
When RCCB trips
Water leakage from heater or washing machine
Wet socket or exposed wiring
Faulty appliances causing leakage
Human contact with live wires (the most dangerous scenario)
In simple words:
RCCB protects you — MCB protects the house.
Key Differences Between MCB and RCCB
| Feature | MCB | RCCB |
|---|---|---|
| Primary Function | Protects wiring & appliances | Protects human life |
| Detects | Overload & short circuit | Leakage current |
| Trips When | Current exceeds limit | Live & neutral imbalance |
| Best Used For | All circuits (lighting, socket, aircond) | High-risk areas (bathroom, kitchen, outdoor) |
| Safety Level | Basic | Advanced |
Do You Need Both MCB and RCCB?
Yes. Every modern home should have both.
MCB without RCCB = Fire protection only
RCCB without MCB = Shock protection but wiring can still burn
Together they form a complete electrical safety system.
Which One Should You Install in Malaysia?
Based on Malaysian household safety requirements:
For Every Home (Minimum Standard)
✔ 1 unit RCCB (63A / 100A depending on load)
✔ Individual MCBs for each circuit (6A / 10A / 16A / 20A / 32A)
For High-Risk Zones
✔ Aircond → 20A / 25A MCB
✔ Water Heater → 20A MCB + proper ELCB/RCCB
✔ Washing Machine → RCCB protection very important
Recommended Upgrade
If your house is older than 10 years:
✔ Replace old MCBs
✔ Install a proper RCCB
✔ Check for burnt or oversized wires
Our shop regularly sees houses in USJ & Subang Jaya where no RCCB is installed—this is extremely dangerous.
Signs You Should Replace Your MCB or RCCB
Replace MCB if:
It trips too easily
It gets hot
It has burn marks
It is older than 8–10 years
Replace RCCB if:
Test button (T) does not work
It trips frequently without reason
It does not trip during leakage
It is an outdated model
If your “TEST button” doesn’t trip when pressed — your RCCB is already failed.
Professional Installation & DB Inspection (Subang Jaya)
If you live anywhere around Subang Jaya, USJ, Puchong, Shah Alam or Klang Valley, you can visit our shop for:
✔ MCB replacement
✔ RCCB installation
✔ DB rewiring
✔ Home circuit inspection
✔ Electrical troubleshooting
✔ Aircond, wiring, renovation services
Shop Information
Sumon Electrical & Hardware Trading
Lot K10004, Ground Floor, Goodyear Court 7, USJ 14, Subang Jaya, Selangor
Google Maps: https://maps.app.goo.gl/CqTZ24KzNDvmfK1y8?g_st=awb
WhatsApp: +601116109510
Website: https://shababalsharif.com
Conclusion
MCB and RCCB are not alternatives—they work together.
One protects the electrical system; the other protects your life.
Installing both ensures maximum safety for your home, shop, or business.
If your DB is old, unstable, or frequently tripping, a quick inspection can prevent fire risks and electrical accidents.