An RCBO, or Residual Current Circuit Breaker with Overcurrent Protection, combines protection against overcurrent and leakage current in one device. Because it provides both types of protection, choosing the correct RCBO is important, especially when it comes to its ampere rating.
Using the wrong rating may affect how well the electrical protection works. Before choosing an RCBO, it is useful to understand the electrical power available in the home and estimate the current required by the installation.
How Do You Determine the RCBO Ampere Rating?
The ampere rating can be estimated from the available electrical power using a basic formula:
I = P / V
Where:
- I = current in amperes (A)
- P = electrical power
- V = voltage
For a typical household installation with a voltage of around 220 V, the electrical power can be divided by 220 to estimate the current.
For example, a home with a 2,200 VA power supply can be calculated as:
2,200 / 220 = 10 A
This makes a 10 A RCBO an initial reference. However, the final choice should not be based on the home's power rating alone.
Match the RCBO Rating with the Home's Electrical Power
Here are some examples based on common household power capacities:
Electrical Power | Calculation | RCBO Reference |
| 900 VA | 900 / 220 = 4.09 A | 4 A |
| 1,300 VA | 1,300 / 220 ≈ 5.9 A | 6 A |
| 2,200 VA | 2,200 / 220 = 10 A | 10 A |
| 5,500 VA | 5,500 / 220 = 25 A | 25 A |
These figures can be used as a starting point when selecting an RCBO. In an actual installation, other factors should also be considered, including cable size, load type, and circuit arrangement.
For example, if a circuit uses a cable with a specific current-carrying capacity, the RCBO should be suitable for that cable. A higher home power rating does not automatically mean that a larger RCBO can be installed without checking the rest of the electrical system.
Do Not Ignore Leakage Current Sensitivity
The ampere rating is not the only RCBO specification that matters. You should also check its leakage current sensitivity, which is measured in mA or milliamperes.
This value is sometimes confused with the ampere rating, even though they serve different purposes. Amperes (A) indicate the RCBO's current rating, while mA indicates how sensitive the device is to leakage current.
30 mA RCBO for Human Protection
An RCBO with 30 mA sensitivity is commonly used to provide additional protection against electric shock. When leakage current reaches the device's sensitivity level, the RCBO can disconnect the electrical circuit.
This is why 30 mA sensitivity is often considered for circuits where protection for people is an important requirement.
100 mA RCBO for Installation Protection
A 100 mA sensitivity can be used for certain installation protection requirements. It can help reduce risks related to leakage current and potential electrical fires caused by electrical faults.
When choosing an RCBO, therefore, do not only look at ratings such as 6A, 10A, or 25A. The leakage sensitivity, such as 30 mA or 100 mA, should also match the purpose of the installation.
Steps to Determine the RCBO Ampere Rating
Choosing the right RCBO can be made easier by following these steps:
1. Check the Home's Electrical Power
First, find out the electrical power capacity of the home, such as 900 VA, 1,300 VA, 2,200 VA, or 5,500 VA.
2. Calculate the Estimated Current
Use the formula I = P / V with a voltage of around 220 V. This gives an estimate of the current based on the available electrical power.
3. Check the Installation
Do not choose the RCBO based only on the calculation. Consider the cable size, electrical equipment, load characteristics, and circuit distribution.
4. Choose the Leakage Current Sensitivity
Once the ampere rating has been considered, check the required leakage sensitivity. For additional protection against electric shock, 30 mA may be suitable depending on the installation design and requirements. For certain installation protection needs, 100 mA may be considered.
Common Mistakes When Choosing an RCBO
One common mistake is assuming that the home's electrical power is the only factor needed to select an RCBO. In reality, cable capacity and load characteristics are also important.
Another mistake is ignoring the mA rating. For example, a 10A 30mA RCBO provides two different pieces of information. The 10A refers to the current rating, while 30mA refers to the leakage current sensitivity.
Choosing the right RCBO means looking at the electrical installation as a whole rather than focusing on just one number on the product label.
Choose an RCBO That Fits Your Installation
Choosing the right RCBO ampere rating can start with a simple calculation based on the available electrical power. A 900 VA supply gives around 4.09 A, 1,300 VA gives around 5.9 A, 2,200 VA gives 10 A, and 5,500 VA gives 25 A. These figures should be treated as an initial reference and checked against the cable size, electrical load, and installation conditions. Leakage current sensitivity is also important, especially when the RCBO is intended to provide additional protection against electric shock. If you are looking for an RCBO for your home or electrical project, you can find a range of RCBO options at Listrik Kita.
