Your DB May Be Missing RCD — High Electrocution Risk

Many Singapore homeowners assume that their home electrical system is fully protected just because the lights turn on and appliances work normally. Unfortunately, this false sense of security leads to one of the most dangerous hidden risks inside HDBs, condos, and landed homes:

⚠️ A distribution board (DB) without an RCD/RCCB exposes you to direct electrocution and fire hazards.

In Singapore, older flats or properties that were never upgraded may still rely on old MCB-only DB boards. While MCBs can protect against overload or short circuits, they do not protect against electric shock or earth leakage — the exact conditions that kill people instantly.

This blog explains:✔ What is an RCD/RCCB✔ How to know if your DB is missing one✔ Why the risk is extremely serious✔ How electrocution actually happens✔ Signs your home electrical system is unsafe✔ What you should do immediately

Let’s break it down in a simple and practical way.

What Exactly Is an RCD / RCCB?

RCD stands for Residual Current Device, also commonly known in Singapore as RCCB (Residual Current Circuit Breaker).

It is a safety device that detects leakage current — electricity escaping from the circuit into unintended areas. For example:

• A wire touching a metal body of an appliance

• A damaged cable made wet

• A person touching a live part accidentally

When an RCD detects leakage, it cuts off electricity in 0.04 seconds, fast enough to save a life.

MCB vs RCD — Most People Confuse Them

MCB = Protects your wiring

✔ Overload✔ Short Circuit

RCD = Protects you

✔ Earth leakage✔ Human-contact shock✔ Wet-area electrocution✔ Faulty appliances leaking current

Without an RCD, an MCB will not trip if someone gets shocked. This is the main reason electrocution still happens in homes worldwide.

Why Missing RCD Is a Critical Danger

1️⃣    Direct Electrocution Risk

If someone touches a faulty appliance or exposed wire, the current travels through the body to the ground.Without an RCD, nothing stops the current — meaning:

🟥 Full voltage passes through the body🟥 Heart rhythm can collapse🟥 Shock lasts long enough to kill🟥 There is no automatic disconnection

This is why RCD is considered the life-saving device in modern electrical safety.

2️⃣   Hidden Wiring Leakage Can Start Fires

Old wiring, loose connections, and damaged insulation cause leakage current.Even a small leakage of 30mA (less than needed to light a bulb) can:

⚠ Heat wires inside walls⚠ Ignite insulation⚠ Melt cable joints⚠ Start slow, smouldering fires

An RCD shuts down the circuit before the fire starts.An MCB only reacts when a big short-circuit happens — usually too late.

3️⃣   Wet Areas Become Extremely Dangerous

In Singapore homes, wet areas like:

• Kitchen

• Bathroom

• Laundry area

• Outdoor balconies

Pose higher risks because moisture conducts electricity.

Without RCD protection:

❌ A single water splash on faulty wiring❌ A wet appliance❌ A leaking heater❌ A damaged extension plug

…can deliver deadly shock instantly.

This is why PUB, BCA, and licensed REWs strongly recommend RCD protection in all homes.

Why Some Homes Still Don’t Have RCD

1️⃣   Old HDBs (pre-1990s) installed MCB-only boards

RCDs were not common in older electrical designs.

2️⃣   Upgrading was never done by the previous owner

Many homeowners assume everything is “okay” simply because the house works.

3️⃣   Renovation contractors skip it to reduce cost

Some ID/renovation companies cut corners and only install MCBs to save money.

4️⃣   Property rented out for years with no electrical checks

Tenants rarely report issues unless major tripping occurs.

5️⃣   Homeowners don’t know what to look for

Most people don’t know the difference between MCB and RCD.

This is why electrical safety checks are so important.

How to Check If Your DB Is Missing RCD (Simple Steps)

Go to your DB box and look for switches labelled:

• RCCB

• RCD

• ELCB

• Earth Leakage

• Test Button (T button)

✔ If you see a large main switch with a TEST button, you have an RCD.

❌ If you only see rows of small MCBs with no test button, your home has no RCD protection.

A typical safe DB has:

• 1 main isolator

• 1 RCCB

• Rows of MCBs separated by circuits

If any of these components are missing or look extremely old, your electrical system is outdated.

Common Warning Signs Your DB Is Unsafe

⚠️ Frequent MCB tripping

Leakage current may be happening but the MCB cannot detect it.

⚠️ Burning smell from DB

Loose neutral/earth connections causing heat buildup.

⚠️ Sparks when plugging appliances

Indicates leakage or unstable supply.

⚠️ Shock or tingling sensation from metal parts

Dangerous — live current may be leaking into the appliance body.

⚠️ Water heater metal body giving mild shock

This is a classic example of earth leakage without RCD protection.

⚠️ Home older than 10–15 years with original DB

Chances of missing or faulty RCD are very high.

If any of these signs appear, get a licensed electrical worker (LEW/REW) to inspect immediately.

How Electrocution Actually Happens at Home

People often think electrocution requires touching a live wire.Not true — most accidents happen from faulty appliances:

• Kettle leaking voltage

• Water heater with damaged heating coil

• Washing machine with faulty earth

• Fridge with worn insulation

• Fan with loose internal wiring

Without RCD, the appliance keeps working even when it’s dangerous.

With RCD, the safety device detects leakage in milliseconds and cuts power, preventing shock.

Upgrading to RCD Is Fast, Simple & Affordable

A modern RCD upgrade usually involves:

✔ Replacing main breaker with RCCB✔ Rearranging circuits✔ Checking earth bonding✔ Testing voltage & leakage✔ Rewiring small internal parts if needed

Most installations are done within 1–2 hours with minimal disruption.

Considering the potential danger, upgrading is one of the most important safety investments you can make.

Why Licensed Electrician Is Required in Singapore

RCD installation must be done by a licensed REW because:

• Wrong wiring can cause more danger

• Wrong earth connection can cause total failure

• Wrong sensitivity level can cause nuisance tripping

• Singapore electrical regulations must be followed

Alpha & Omega Trinity Pte Ltd engages Singapore-licensed electricians trained to handle residential and commercial electrical works.

Protect Your Family — Don’t Wait for an Accident

Electrical shocks and fires happen silently.A home can look perfectly normal on the outside while the DB is dangerously outdated inside.

Ask yourself:

✔ When was the last time your DB was checked?✔ Is your RCD working?✔ Do you know if your home even has one?

If the answer is no, it’s time for a proper inspection.

Need Help? We Provide Professional Electrical Safety Services

Alpha & Omega Trinity Pte Ltd provides:

🔧 DB inspection & safety assessment🔧 RCD / RCCB installation & upgrading🔧 Wiring health check

🔧 Troubleshooting of shocks & frequent tripping🔧 Replacement of faulty components🔧 REW-certified electrical work

We ensure your home meets modern safety standards and protect your family from hidden electrical dangers.

Contact Us Today

Alpha & Omega Trinity Pte Ltd📞 Call/WhatsApp: +65 8151 8857🌐 www.aotrinitysg.com⚡ Your trusted Singapore electrical safety specialist