As EV charging infrastructure expands rapidly across Europe and the UK, engineers are facing a critical challenge with Residual Current Sensors:

How to ensure electrical safety while meeting strict compliance standards?

Residual current sensors are no longer optional components—they are essential for system protection, certification, and user safety.

In this guide, we break down exactly how professional engineers evaluate and select the right residual current monitoring solution.

Why Residual Current Detection Matters?

Residual current detection plays a vital role in preventing:

Electric shock hazards

Fire risks caused by insulation failure

System damage due to leakage faults

In EV charging systems and power converters, leakage current is unavoidable due to:

High-frequency switching

EMI filters

Capacitive coupling

If not properly detected, even small leakage currents can lead to serious safety incidents.

⚡ Why AC/DC Residual Current Detection Is Critical?

One of the most overlooked risks in modern systems is DC leakage current.

Traditional protection devices (Type A RCDs) can:

Detect AC leakage

BUT fail when exposed to DC components

The Risk:

DC leakage current above 6mA can:

Saturate the magnetic core of RCDs

Disable protection functionality

Leave users completely unprotected

This is why engineers increasingly search for:

AC DC leakage current sensor

6mA DC residual current detection module

✅ The Solution:

Use a combined AC/DC residual current monitoring unit capable of:

Detecting both AC and DC leakage

Triggering reliable trip signals

Maintaining protection integrity

How Engineers Ensure IEC 62955 Compliance?

For EV charging systems, compliance with IEC 62955 (RDC-PD) is mandatory.

Engineers must ensure their design includes:

✔ 1. 6mA DC Detection Capability

The system must detect DC leakage current at or above 6mA.

✔ 2. AC + DC Monitoring

Combined residual current detection is required—not just AC.

✔ 3. Reliable Trip Output

The system must trigger a disconnection when thresholds are exceeded.

✔ 4. Self-Test Functionality

To ensure long-term reliability and fault detection.

Practical Engineering Solution

A well-designed residual current monitoring unit (such as the HYCA-01) integrates:

AC/DC leakage detection (DC threshold ~4.5–6mA)

Dual trip outputs (30mA AC / 6mA DC)

PWM signal output for real-time monitoring

Built-in self-test function

IEC 62955 & IEC 62752 compliance support

This allows engineers to meet compliance without complex redesign.

 

What Engineers Really Compare?

When sourcing residual current sensors, engineers don’t just compare price—they evaluate performance across multiple dimensions:

1.Detection Capability

Can it detect both AC and DC leakage?

Does it meet the 6mA DC requirement?

2.Compliance

IEC 62955 (EV charging)

IEC 62752

3.Output Signal Type

Digital (trip signals)

PWM (for monitoring & MCU integration)

Analog (less common in modern systems)

4.Integration & Design

PCB mounting vs external device

 

Size and ease of installation

Compatibility with control systems

5.Reliability & Safety Features

Self-test function

Fault output signal

Long-term stability

6.Measurement Accuracy

Low error (e.g., ±0.5mA level)

Stable performance under temperature variation

Compay：HEYI Electrical Co., Ltd.
Brand: HEYI/ASCT
Contact: Bethy
E-mail: heyi@heyiele.com             
Tel: 86-13968747975

--- END ---