Residual Current Device Supplier
Residual Current Devices Matched to the Circuit and Load
Start with the protection function, not the housing. SENTOP helps buyers compare RCCBs, RCBOs and application-specific residual-current solutions by system voltage, residual-current waveform, IΔn, poles, overcurrent function and destination requirements.
RCD Meaning and Scope
RCD is a protection family, not one interchangeable product
A residual current device responds to an imbalance between the live conductors of a circuit. The correct product depends on whether the project needs automatic disconnection, integral overcurrent protection, monitoring only or a dedicated residual DC detection function.
Do not replace one RCD family with another from appearance alone. Product standard, function, waveform capability, rated residual operating current and system coordination must remain connected to the exact model.
Detect the imbalance
All monitored live conductors pass through the sensing system. Current returning by an unintended path creates residual current.
Match the response
The product may trip, combine tripping with overcurrent protection, issue an alarm or coordinate with another protective device.
Match the waveform
Loads with rectifiers, variable-speed drives, inverters and charging electronics can change the residual-current waveform the device must detect.
Verify the installation
Correct neutral routing, earthing, upstream protection, commissioning tests and periodic checks are part of the protection system.
Residual Current Device Selection
Choose the function before the model and rating
A useful enquiry connects the protection objective, circuit, connected equipment and destination requirements to one product standard and one exact configuration.
Protection objective
Define protection against electric shock, fire-risk reduction, equipment leakage monitoring, EV residual DC detection or another documented requirement.
RCCB, RCBO or monitor
Confirm whether the device must disconnect on residual current, also protect against overcurrent, or provide monitoring and an alarm for a supervised system.
System and earthing
Send voltage, frequency, single- or three-phase arrangement, earthing system, neutral treatment, circuit role and installation location.
Connected equipment
Identify rectifiers, drives, inverters, UPS equipment, EV chargers, filters and other electronics that can affect residual-current shape and standing leakage.
Waveform type
Select Type AC, A, F or B from the possible residual-current components and the equipment manufacturer's instructions, not from price alone.
Sensitivity and time
Confirm IΔn, instantaneous or delayed operation, selectivity requirements and the expected cumulative leakage of downstream equipment.
Exact product scope
Verify poles, rated current, short-circuit data, backup protection, terminals, dimensions, supply dependence, standard, certificate and target market.
Residual Current Product Directions
Start with the required device function
These directions organize an RFQ. Final supply is based on the exact product data, certificate scope, installation rules and connected equipment.
RCCB
Choose an RCCB where residual-current disconnection is required and overload and short-circuit protection is provided separately.
RCBO
Choose an RCBO when one device must provide residual-current protection together with overload and short-circuit protection for the circuit.
Type B RCD
A direction for systems that can produce smooth DC and specified higher-frequency residual-current components within the selected product's capability.
EV Residual DC Solution
Coordinate the charging equipment's residual DC detection with the required upstream AC residual-current protection and installation design.
Replacement reminder: send the full model, front and side photos, wiring diagram, rated voltage, current, poles, IΔn, waveform symbol, trip curve or time characteristic, breaking or conditional short-circuit data, terminals, dimensions and destination approval.
Residual Current Waveform Types
Match detection capability to the electronics behind the circuit
The AC, A, F and B marking describes residual-current waveforms the RCD is designed to detect under its product standard. It is different from the B, C or D overcurrent trip curve marked on an MCB or RCBO.
Type AC
Responds to residual sinusoidal alternating currents within the exact product's declared conditions.
Type A
Adds response to pulsating DC residual currents within its specified conditions.
Type F
Extends Type A behavior for specified composite residual currents from selected single-phase frequency-controlled equipment.
Type B
Covers specified AC, pulsating DC, composite-frequency and smooth DC residual currents within its declared range.
Do not assume a waveform type from the application name alone. The power-conversion topology, possible DC content, switching frequency, equipment instructions and local installation requirements determine the suitable direction.
RCD Standards and Functional Boundaries
Verify the standard that matches the actual product function
A standard number on a related device is not enough. Confirm the exact product family, model scope, edition, certificate owner, markings and destination-market acceptance.
IEC 60755
Provides general minimum requirements and information for standards covering residual-current operated protective devices. It helps define the RCD family; it is not a substitute for the applicable product standard.
IEC 61008
Covers residual-current operated circuit-breakers without integral overcurrent protection within its stated scope. Confirm backup protection and conditional short-circuit data.
IEC 61009
Covers residual-current operated circuit-breakers with integral overcurrent protection within its stated scope. Confirm trip curve, breaking capacity and residual-current type together.
IEC 62423
Adds requirements for Type F and Type B residual-current operated circuit-breakers. Verify the exact waveform and frequency capability declared for the product.
IEC 62020-1
Addresses RCMs for household and similar uses within its scope. A warning or monitoring function must not be presented as automatic protective disconnection unless the complete system provides it.
IEC 62955
Addresses RDC-DDs for permanently connected mode 3 AC EV charging stations within its scope. Confirm how the function coordinates with the charging equipment and upstream RCD.
Residual Current Protection Applications
Different loads can require different RCD behavior
Application labels are only the starting point. The exact equipment topology and installation design decide the required protection function and waveform capability.
RCD Quotation Checklist
Send the system and load data for a faster quotation
You can begin with a model number, nameplate photo, one-line diagram, equipment manual or basic circuit data. We will identify the remaining points that need confirmation.
Describe the circuit
Voltage, frequency, phase, earthing arrangement, protected load, one-line diagram, installation location and destination country.
Define protection
RCCB, RCBO, monitoring or EV detection; poles, In, IΔn, Type AC/A/F/B, time behavior and overcurrent coordination.
Confirm the order
Existing model or sample, certificate, dimensions, terminals, quantity, OEM label, packaging, documents and delivery schedule.
RCD Installation and Fault Diagnosis
Diagnose the complete circuit, not only the device
Repeated tripping can indicate a real fault, wiring error, cumulative leakage, incompatible waveform type or damaged equipment. Repeatedly resetting the device without testing can hide a serious condition.
RCD Model Verification and Supply
Build repeat orders around an approved protection specification
For panel builders, equipment manufacturers and distributors, a stable RCD order depends on configuration control. Similar dimensions or markings do not prove equal protection behavior.
Related Low-Voltage Protection
Continue planning the complete protection system
Residual Current Device FAQ
RCD selection questions
Use these answers to prepare the technical information required for model matching, replacement and procurement.
What is a residual current device?
A residual current device detects an imbalance between the monitored live conductors and responds according to its product function and declared characteristics. The RCD family includes protective circuit-breakers and related residual-current functions, so the exact device type must be identified.
What is the difference between an RCD and an RCCB?
RCD is the broad term for residual-current devices. An RCCB is one RCD product family that provides residual-current protection without integral overload and short-circuit protection.
What is the difference between an RCCB and an RCBO?
An RCCB provides residual-current protection and requires separate overcurrent protection. An RCBO combines residual-current protection with overload and short-circuit protection in one specified device.
What do RCD Types AC, A, F and B mean?
They identify residual-current waveform capabilities. Type AC covers residual sinusoidal AC, Type A adds pulsating DC, Type F extends Type A for specified composite frequencies, and Type B adds specified smooth DC and wider frequency behavior. Confirm the exact product data.
What does 30 mA mean on an RCD?
It is the rated residual operating current IΔn, not the normal load-current rating. A 30 mA direction is commonly associated with additional protection in applicable circuits, but the complete installation still requires correct earthing, wiring and verification.
When should a Type B RCD be considered?
Type B is considered when equipment can produce smooth DC or specified higher-frequency residual currents, such as selected drives, inverters, charging systems and power converters. Verify the equipment topology, IEC 62423 scope and manufacturer instructions.
Is a residual current monitor the same as a protective RCD?
No. An RCM monitors residual current and provides a prescribed warning or signal within its scope. It is not automatically equivalent to a protective RCD that disconnects the circuit unless the complete designed system provides and verifies that protective function.
What is an RDC-DD for EV charging?
An RDC-DD detects residual direct current for applicable permanently connected mode 3 AC EV charging equipment within IEC 62955 scope. Its operation must be coordinated with the charger design, upstream RCD and local installation requirements.
Why does an RCD trip repeatedly?
Possible causes include insulation faults, moisture, cumulative leakage, shared neutrals, downstream neutral-to-earth connections, incorrect wiring, an unsuitable RCD type or faulty equipment. Qualified personnel should isolate and test the circuits instead of repeatedly resetting the device.
Does the RCD test button prove the installation is safe?
No. The test button checks the product's internal test path under the documented supply conditions. It does not verify earthing, neutral separation, external wiring, actual trip current or trip time, so appropriate commissioning and periodic tests may also be required.
Can SENTOP support OEM and bulk RCD orders?
Eligible residual-current product configurations can be reviewed for samples, model matching, repeat supply, labels, packaging, documentation and OEM requirements. Feasibility, approval scope, quantity and destination requirements are confirmed for the requested model.
Residual Current Protection Support
Send your circuit, load or existing RCD model
SENTOP can review residual current device requirements for new projects, replacements, samples, OEM panels, distributor ranges and bulk orders.
