RCD vs RCBO: Simple UK Homeowner Guide for 2026 (What’s the Difference?)
RCD vs RCBO: Simple UK Homeowner Guide for 2026 (What’s the Difference?)
Confused about the difference between an RCD and an RCBO? You're not alone. This simple 2026 guide explains what each device does, how they protect your home, why they sometimes trip, and whether you should upgrade to RCBO protection.
⚡ What Is an RCD?
An RCD (Residual Current Device) is a safety device that protects you from electric shock. It works by constantly monitoring the balance of electricity flowing through a circuit. If the device detects electricity leaking to earth — even a small amount — it cuts the power almost instantly.
RCDs protect you, not the wiring. They help prevent serious injury or electrocution in the event of a fault.
What an RCD protects against:
- Electric shock
- Earth leakage faults
- Some wiring or appliance faults
⚡ What Is an RCBO?
An RCBO combines the functions of:
- an RCD (shock protection)
- an MCB (overload and short-circuit protection)
That means an RCBO protects both you and the wiring.
What an RCBO protects against:
- Electric shock
- Earth leakage faults
- Overloaded circuits
- Short-circuits
This makes RCBOs the most advanced protective device in a modern consumer unit.
🔍 RCD vs RCBO — What’s the Actual Difference?
| Feature | RCD | RCBO |
|---|---|---|
| Protects from electric shock | ✔ Yes | ✔ Yes |
| Protects wiring from overloads | ✖ No | ✔ Yes |
| Protects from short-circuits | ✖ No | ✔ Yes |
| One device protects… | Multiple circuits | One single circuit |
| Nuisance tripping | Common | Rare |
| Recommended in 2026? | Good | ✔ Best choice |
👍 Why RCBOs Are Better in Most UK Homes
RCBOs offer several advantages over traditional RCD + MCB setups:
1. Fewer nuisance trips
An RCD protects multiple circuits at once. If one circuit has a minor fault, the entire RCD block can trip.
With RCBOs, only the faulty circuit trips.
2. Better safety
Because RCBOs offer three types of protection, your home is more secure against a wider range of faults.
3. Easier fault-finding
With RCBOs, you always know which circuit has the issue — much simpler to diagnose.
4. Recommended by modern regulations
While not mandatory in every home, RCBOs are now the preferred choice in most consumer unit upgrades.
🤔 Why Does an RCD Keep Tripping?
An RCD might trip because of:
- A faulty appliance
- Moisture in a socket or outdoor circuit
- Worn insulation on wiring
- Leaking heating elements (kettle, washing machine, dishwasher)
- Damaged cables (DIY nails through walls, etc.)
Because an RCD protects multiple circuits at once, the source isn’t always obvious.
🤨 Why Does an RCBO Trip?
RCBOs trip for one of three reasons:
- Earth leakage (shock protection)
- Overload (too many appliances on one circuit)
- Short-circuit (fault in the wiring)
An RCBO only affects the circuit it’s assigned to — making faults easier to locate.
🏆 RCD or RCBO — Which Should You Choose in 2026?
If you're upgrading your consumer unit in 2026, RCBOs are the best choice.
You should choose RCBOs if you want:
- Maximum protection
- Less nuisance tripping
- Safer, modern electrics
- Clearer fault identification
Dual RCD setups are still safe and widely used, but they are gradually being replaced by RCBO-only boards, especially when combined with SPDs.
🔎 Types of RCD (Simple Explanation)
There are several types of RCD used in UK homes:
- Type AC — Obsolete in most homes
- Type A — Standard for modern homes
- Type F — Used for some appliances
- Type B — Required for EV chargers and solar
- S-Type (Time Delayed) — Used as main incomer RCDs
🔎 Types of RCBO
RCBOs also come in different types:
- Single-module RCBO — slim, modern design
- Double-module RCBO — older and bulkier
- Type A RCBO — standard choice in homes
- Type B RCBO — specialised EV/solar use
💷 Costs of RCDs & RCBOs in 2026
| Device | Typical Cost (Device) | Installed Cost (Approx) |
|---|---|---|
| RCD | £18 – £45 | £60 – £120 |
| RCBO | £22 – £55 | £60 – £140 |
| Full RCBO board upgrade | £380 – £780 | £520 – £950 |
❓ RCD vs RCBO — FAQs
Is an RCBO safer than an RCD?
Yes. RCBOs offer three layers of protection instead of one: shock protection, overload protection and short-circuit protection.
Why does my RCD keep tripping?
Most RCD trips are caused by faulty appliances, moisture, damaged wiring or earth leakage faults. Because one RCD protects multiple circuits, it can be hard to track down the source.
Why does my RCBO trip?
RCBO trips are usually easier to diagnose because only the specific faulty circuit will disconnect.
Do all new consumer units need RCBOs?
No, but RCBO-only boards are now the preferred choice due to better discrimination, fewer trips and clearer fault finding.
Do I need a special RCD for an EV charger?
Most EV chargers require a Type B RCD or equivalent protection. Your electrician will confirm the correct device.
📞 Book an Electrician (South Coast)
Thinking about upgrading your consumer unit, replacing RCDs or switching to RCBOs?
We cover: Portsmouth, Southampton, Fareham, Gosport, Havant, Chichester, Waterlooville & surrounding areas.
- RCBO consumer unit upgrades
- RCD & RCBO replacements
- Electrical fault finding
- Home safety checks
Contact us today for a fast quote.