Understanding the real reasons behind MCB tripping in Malaysian homes & shops
In many Malaysian homes, shops, and offices, one of the most common electrical problems is the MCB (Miniature Circuit Breaker) suddenly tripping. When this happens, the lights go off, sockets stop working, or the entire DB board shuts down.
But why does this happen?
In this guide, we will explain the real reasons behind MCB tripping, how dangerous it can be, and what you should do before calling an electrician.
What Is an MCB? (Simple Explanation)
An MCB is a safety device inside your DB board. Its job is to protect your home from:
Overload
Short circuit
Electrical fire
Wire damage
Whenever it detects something unsafe, it automatically trips to protect you.
Top 7 Reasons Why MCB Trips in Malaysia
1️⃣ Overload — Too Many Appliances in One Circuit
When one circuit carries too much load, the MCB will trip.
Common Malaysian examples:
Water heater + iron + washing machine
Aircond + microwave on same line
Too many multi-plug extensions
Shop freezers & water heaters on same circuit
Solution:
Reduce load or upgrade the wiring/circuit.
2️⃣ Short Circuit — Very Dangerous ⚠️
A short circuit happens when the live wire touches neutral or earth.
MCB instantly trips to prevent fire or major damage.
Signs:
Burning smell
Sparks
Black marks near socket
Loud “tuck” sound
Solution:
Call an electrician immediately.
3️⃣ Faulty Appliances
Sometimes the issue comes from a damaged appliance.
Common faulty items:
Water heater
Iron
Washing machine
Aircond compressor
Electric kettle
Rice cooker
Unplug the item and test again.
4️⃣ Loose or Burnt Socket / Switch
This is very common in old houses and shoplots.
Symptoms:
Socket becomes hot
Plug feels loose
Burning smell
MCB trips when using the socket
Solution:
Replace the socket immediately.
5️⃣ Wiring Problems (Old or Damaged Cables)
Old cables or damaged wiring can cause overheating and short circuits.
Common causes:
Worn-out wiring
Rat-chewed cables
Thin cables used for high load
Cheap renovation wiring
6️⃣ Water Leakage near Electrical Points
Roof leaks, bathroom leaks, or wall seepage can cause tripping.
Especially during heavy rain.
7️⃣ Faulty or Weak MCB Unit
Sometimes the MCB itself is old or defective.
Recommended brands:
EPS, Schneider, Legrand, Hager
Should You Reset the MCB Yourself?
Yes — but safely.
Steps:
Turn off all heavy appliances.
Switch the MCB fully OFF.
Switch ON again.
If it trips again → there is a real problem.
Do NOT force it repeatedly.
When Should You Call a Professional Electrician?
Call immediately if you notice:
Burning smell
Socket heating up
MCB trips repeatedly
Sparks from switch
Water leaking near wiring
Aircond keeps tripping
DB board making noise
These are fire-risk issues.
Professional Electrical & Hardware Services in Subang Jaya
If you need electrical repair, aircond service, wiring work, or hardware support, our team at Sumon Electrical & Hardware Trading is ready to assist.
📍 Shop Location:
Lot K10004, Ground Floor, Goodyear Court 7,
USJ 14, Subang Jaya, Selangor
(Click for Google Map)
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+6011 1610 9510
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Electrical • Aircond • Plumbing • Minor Renovation • Hardware Supply • Installation • Troubleshooting