Engineering Guide
IEC 62752 IC-CPD: residual current protection for Mode 2 portable EV chargers
What an in-cable control and protection device is, why it must detect both AC and smooth DC residual current, and how compact sensors fit inside a portable charger box.
A Mode 2 portable charger, the “charging cable with a box in the middle”, is often the first charger an EV owner uses. It plugs into an ordinary household or industrial socket, so it cannot rely on the building to provide the right protection. That is why IEC 62752 puts the safety functions inside the cable itself, in a device called the IC-CPD. This guide explains what the standard expects from that device and how to choose a residual current sensor that fits inside it.
What is an IC-CPD?
IC-CPD means in-cable control and protection device. It sits in the charging cable between the supply plug and the vehicle connector and combines several jobs:
- Control: it talks to the vehicle over the control pilot signal, tells the vehicle how much current it may draw, and only energises the vehicle connector when the vehicle is ready.
- Switching: it contains relays that connect and disconnect the supply to the vehicle.
- Protection: it detects residual current and opens the relays when a leakage fault occurs.
IEC 62752 is the international product standard for this device. China has a corresponding national standard for Mode 2 in-cable devices, and charger makers serving several markets usually design one platform that can meet both sets of tests.
Why the IC-CPD must detect both AC and DC leakage
In a fixed wallbox installation the electrician chooses the upstream RCD. With a portable charger, nobody knows what is upstream. The socket may be protected by a Type A RCD, by an older Type AC RCD, or in some buildings by no RCD at all.
At the same time, the vehicle’s on-board charger can produce smooth DC fault current if its insulation fails. Smooth DC can saturate a conventional RCD core and stop it from tripping. (We explain this in Type A vs Type B RCD for EV chargers.)
So the IC-CPD has to protect on its own, against:
- AC residual current at the familiar 30 mA personal-protection level,
- pulsating DC residual current, and
- smooth DC residual current at the 6 mA level.
This is exactly the “Type A + DC 6mA” detection function that EVsense sensors provide. In the datasheets, the relevant values are:
| Waveform | Trip current (min / typ / max) | Typical trip time |
|---|---|---|
| Smooth DC | 3 / 4.5 / 6 mA | 380 ms at 6 mA, 11 ms at 300 mA |
| AC 50 Hz | 15 / 22 / 30 mA | 115 ms at 30 mA, 15 ms at 150 mA |
| F IC_CPD waveform | 15 / 28 / 42 mA | 15 ms at 210 mA |
Values are from the 4R2Z datasheet. The sensor outputs a digital TRIP signal and the IC-CPD controller opens the relays.
Why sensor size matters so much in Mode 2
A portable charger box has to be light, sealed and small enough to lie on a garage floor or hang on a wall hook. Inside, the PCB carries the controller, relays, power supply, pilot circuit and temperature monitoring. There is very little room left for a residual current detection block.
That makes three sensor properties important:
- Compact, PCB-mounted format. The sensor should solder directly to the main board, without a separate harness.
- Pre-wired conductors. For single-phase Mode 2 designs, a sensor with built-in line and neutral conductors avoids threading cables through an aperture during assembly. That saves labour and removes a source of assembly errors.
- Integrated functions. If the same magnetic part also provides current or voltage measurement, you can remove other components from the board.
EVsense options for IC-CPD designs
4R2Z is designed for Mode 2 IC-CPDs to IEC 62752. It is PCB-mounted, pre-wired for single-phase, and measures about 30.6 × 23 × 16 mm. It has a 5 V supply, digital TRIP output and built-in self-test. For many portable charger designs it is the simplest drop-in choice.
CT1719 is a detection ring with an integrated current transformer, pre-wired for single-phase 20 A and PCB-mounted. It works with the external ILM2112TQC residual current detection IC. The integrated CT (rated 20 A input, 20 mA output, ratio error below ±0.1 % at rated current) lets the same part measure charging current, which is useful when you want to remove a separate CT. This chip + core approach gives you more control over the board layout. Learn more in how 6mA DC residual current detection works.
2R4Z combines Type A + DC 6mA detection with current transformer and voltage detection functions, in a PCB-mounted package with two 4.5 mm apertures. It is used in both Mode 2 and Mode 3 chargers, so it suits manufacturers who want one sensing block across a portable and a wallbox product.
Design tips for Mode 2 boards
- Run the self-test at every power-up and before each session. IC-CPDs are unplugged and replugged often; the sensor recalculates its zero point during the self-test, which keeps the DC threshold accurate.
- Wait for the sensor to start. There is an 800 ms start-up delay after power-on. Do not close the relays until the self-test is complete.
- Use a clean 5 V supply. The datasheets recommend a 5 V LDO with low ripple, because the detection works at the milliamp level.
- Keep distance from the relays. Relay coils and contacts create magnetic fields; the datasheets recommend at least 3 cm spacing.
- Watch the Y-capacitors. Leakage from switching power supply Y-capacitors can pass through the sensor. Place the sensor so that this current does not flow through the detection core.
More detail is in our RCD sensor PCB integration guide.
Mode 2 vs Mode 3: same sensor family, different standard
The same Type A + DC 6mA detection principle is used in Mode 3 wallboxes, where the relevant standard is IEC 62955 (RDC-DD). The main differences are mechanical: Mode 3 chargers often need larger apertures for higher currents or three-phase conductors, while Mode 2 boxes need the smallest possible footprint. If you build both product types, choosing one supplier for both simplifies qualification and purchasing.
Summary
- IEC 62752 defines the IC-CPD, the control and protection box inside a Mode 2 charging cable.
- Because the upstream protection is unknown, the IC-CPD must detect AC residual current and smooth DC residual current at the 6 mA level itself.
- Compact, pre-wired, PCB-mounted sensors such as the 4R2Z and CT1719 are built for this job.
- Need a recommendation for your portable charger? Send us your board size and rated current or read how to choose an RCD sensor.
Frequently asked questions
What is an IC-CPD?
IC-CPD stands for in-cable control and protection device. It is the control box built into a Mode 2 charging cable, between the household plug and the vehicle connector. It handles the control pilot communication with the vehicle and provides residual current protection. IEC 62752 is the product standard for IC-CPDs.
Why does a Mode 2 charger need its own DC 6mA detection?
A portable charger is plugged into ordinary socket-outlets, where the upstream protection is often a Type A or even Type AC RCD, or none at all. Smooth DC leakage from the vehicle could blind those devices. The IC-CPD therefore has to detect both AC residual current and smooth DC residual current itself.
Which EVsense sensor is designed for Mode 2 IC-CPDs?
The 4R2Z and CT1719 are designed specifically for Mode 2 IC-CPD use and come pre-wired for single-phase conductors. The 2R4Z, which also integrates voltage and current transformer functions, is used in both Mode 2 and Mode 3 designs.
What does the F IC_CPD value in the datasheet mean?
It is the trip current for the residual current waveform defined for IC-CPD testing. EVsense sensors publish 15 mA min, 28 mA typ and 42 mA max for this waveform, with a typical trip time of 15 ms at 210 mA.
Need help choosing a sensor?
Send your charger platform, target standard, rated current and PCB space. Our engineers reply with a model recommendation, datasheets and sample options.