A practical guide for B2B buyers to select the right RCCB
How to choose an RCCB should consider the correct amp rating; poles, RCCB type, residual-current sensitivity, system arrangement and overcurrent protection need to be checked together.
2-pole RCCB: For single-phase circuits.
4-pole RCCB: For three-phase four-wire systems.
This article is serves as an RCCB guide; the final selection should refer to project drawings and local electrical regulations.
The choice depends on conductor arrangement and switching requirements of the electrical system.
| Decision Point | 2 Pole RCCB | 4 Pole RCCB |
| Typical system | Single-phase | Three-phase four-wire |
| Pole configuration | Line + neutral | L1 + L2 + L3 + neutral |
| Common application | Final distribution / small distribution board | Three-phase distribution board / main or sub-distribution |
| Must also confirm | Voltage, rated current, sensitivity, RCCB type | Phase system, neutral arrangement, rated current, sensitivity, RCCB type and coordination |
This table is only a starting point.
For example, two projects use a 4-pole RCCB, but require different RCCB types or residual-current sensitivities due to varying load characteristics, application requirements and residual-current waveforms. That’s why RCCB selection should be treated as a combination of several decisions, rather than simply choosing “2P or 4P.”
An RCCB, or Residual Current Circuit Breaker, provides residual-current protection.
It does not provide protection against overload or short-circuit current.
This means an RCCB should not simply regarded as a replacement for devices such as:
MCB; MCCB; fuse; or other suitable overcurrent protective devices.
A complete protection arrangement should account for residual-current protection and overcurrent protection.
As a buyer or panel builder, this means they may ask:
“What RCCB amp rating do I need?”
is usually not enough.
You should also understand how the RCCB will coordinate with the upstream or downstream overcurrent protective device.
After confirming the RCCB pole configuration, select the appropriate RCCB type based on residual-current characteristics.
What type of residual current must use the RCCB detect?
RCCB Type Comparison
| RCCB / RCD Type | Generally Associated With | Buyer Caution |
| Type AC | Sinusoidal AC residual current | May not suit some modern electronic loads |
| Type A | AC and pulsating DC residual current | Commonly considered for many modern circuits |
| Type F | Mixed-frequency residual-current conditions | Confirm suitability for frequency-controlled single-phase loads |
| Type B | Residual-current conditions including smooth DC | Confirm suitability for applications such as VFD, EV or PV systems and check the applicable standard |
Not necessarily.
A Type B RCCB is capable of detecting residual-current conditions, including smooth DC residual current.
This makes Type B relevant to certain applications involving equipment such as variable-frequency drives; EV-related equipment; photovoltaic systems; and other electronic loads where the residual-current waveform requires it.
However, this does not mean that Type B should automatically be selected for every project.
RCCB type should be selected based on actual load conditions and project requirements.
A better question is:
“What residual-current waveform can occur in this application, and what RCCB type is required by the equipment and applicable electrical rules?”
Residual-current sensitivity is an important specification to confirm.
It may show: 30mA; 100mA; or 300mA.
The rated residual operating current is commonly represented by IΔn.
| Sensitivity | Common Selection Context | What Must Be Confirmed |
| 30mA | additional/personal protection requirements | Circuit purpose, local requirements and leakage level |
| 100mA | equipment or upstream protection contexts | Selectivity, load leakage and system design |
| 300mA | upstream/fire-protection-related contexts | Local rules, system design and downstream coordination |
Modern equipment may usually produce a certain amount of leakage current.
When several loads are connected downstream of the same RCCB, the leakage can accumulate.
If ignoring this during design, the system may experience unwanted or nuisance tripping.
For larger distribution systems, we also need to take into account selectivity between upstream and downstream protective devices.
Confirm the actual voltage and frequency of the electrical system.
Don’t select the RCCB merely rely on the number of poles.
According to the electrical design and its coordination with the rest of the protection system, determine the required RCCB rated current.
Confirm if the project need 30mA, 100mA, 300mA or another specified value.
When determine the required RCCB type, consider expected residual-current waveform and project requirements.
Confirm what MCB, MCCB, fuse or other overcurrent protective device can be used with the RCCB.
Do not forget: RCCB residual-current protection does not replace overload and short-circuit protection.
Check the panel layout and available installation space.
Confirm if you require specific documentation, standards or certificates before quotation.
Same as 4-pole RCCB, these are additional considerations.
Identify the actual phase and neutral arrangement of the system.
A 4-pole RCCB is typically associated with three-phase four-wire arrangement, but the final selection should be confirmed according to project design.
Determine whether the neutral conductor needs to be switched rely on the system design and applicable local requirements.
Provide the required electrical ratings rather than requesting a generic “4 pole RCCB.”
According to the protection purpose and distribution design, determine the required IΔn.
A three-phase system does not automatically mean you should use Type B.
Consider load characteristics and expected residual-current waveform when choosing the RCCB type.
For main and sub-distribution systems, upstream and downstream protection coordination may be an important part of the design.
Before ordering, confirm installation space, project documentation and certificate requirements.
RCCB connection diagram;
2 pole RCCB connection diagram;
4 pole RCCB connection diagram;
single phase RCCB connection diagram; and
3 phase RCCB connection diagram.
Above is search terms.
However, different RCCB products can have different terminal layouts; a generic diagram found online should not be used as a universal installation instruction.
Final wiring should be carried out or confirmed by appropriately qualified personnel according to the project and local requirements.
For procurement purposes, the more useful question is often not:
“Can you send me an RCCB connection diagram?”
but:
“Can you confirm the correct RCCB model and provide the relevant product datasheet and terminal information for my system?”
By checking several basic specifications before requesting a quotation, you can avoid many problems.
You should also consider specifying poles, sensitivity or RCCB type.
RCCB and overcurrent protective devices perform different protection functions.
The complete protection arrangement should account for residual-current protection and overcurrent protection.
Type B is not a premium version of Type A.
The correct type depends on residual-current characteristics and application requirements.
Match the electrical system and conductor arrangement when selecting pole.
Multiple downstream loads can contribute to total leakage current.
If you are selecting sensitivity and arranging circuits, you need to consider it.
When requesting a quote, do not just send:
“Need RCCB price.”
Send the key electrical and project specifications.
Providing complete technical information before quotation can help suppliers confirm the correct product and prepare a faster quotation.
Prepare the following checklist before quoting:
We need an RCCB for a [single-phase / three-phase] system. Required specification: [2P / 4P], [rated current], [30mA / 100mA / 300mA], [Type A / Type B / other], [voltage/frequency], quantity [XX pcs], for [destination market]. Please confirm the suitable model and available documentation.
Providing this information gives the supplier a much clearer basis for model confirmation.
Send your RCCB requirements to OOHMAGE for model and document confirmation before quotation.
This guide can help narrow down an RCCB selection, but it cannot cover every project requirement.
It does not replace:
If any of these requirements conflict with a general selection example in this article, the specific project requirement should take priority.
A 2-pole RCCB is typically used in single-phase systems and monitors/switches line and neutral. A 4-pole RCCB is typically used in three-phase four-wire system systems and monitors/switches three phases and neutral. Final selection still depends on the electrical system, project design and product specifications.
A 4 pole RCCB is typically associated with three-phase four-wire applications. However, the required pole arrangement should always be confirmed according to the actual system and project design rather than selected from a general rule alone.
An RCCB is designed for residual-current protection and does not provide integral overload or short-circuit protection.
Appropriate overcurrent protection, such as an MCB, MCCB or fuse, must be considered separately according to the electrical design.
No.
Type B RCCBs are designed to detect residual-current conditions including smooth DC, making them relevant to certain applications.
Type A and Type B serve different application requirements. The correct choice depends on the load, expected residual-current waveform, applicable standards and local electrical requirements.
30mA refers to the RCCB’s rated residual operating current, often expressed as IΔn.
The correct sensitivity should be selected according to the required protection purpose, circuit design, leakage current and applicable requirements.
Buyers may want to confirm terminal arrangement, phase and neutral paths, source/load orientation or how the RCCB fits into a distribution board.
Rather than relying on a generic online diagram, buyers should confirm the specific product datasheet, terminal markings, project single-line diagram and local requirements.
The answer depends on the protection arrangement required by the project.
An RCCB provides residual-current protection but does not include integral overcurrent protection. If the project requires both residual-current protection and overcurrent protection, select between RCCB and RCBO based on the overall system design.
When quoting, you can ask:
“Here is my system, pole requirement, rated current, sensitivity, RCCB type, voltage, quantity and destination market. Please confirm the suitable RCCB model and documentation.”
Continue with the matching product range and the supporting selection guides below.
