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[BL602] BL602 PTBLU-W WiFi Module Pinout and Specs in EARU EAKCB-EWE-M Circuit Breaker

ProfAnderson 387 10
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  • Here's details and pinouts for the EARU model EAKCB-EWE-M circuit breaker, purchased from AliExpress in Jun 2025:
    https://www.aliexpress.com/item/1005006189189642.html
    [BL602] BL602 PTBLU-W WiFi Module Pinout and Specs in EARU EAKCB-EWE-M Circuit Breaker

    There's 6 rivets holding the case; you can just drill them out and then the case opens easily. The circuit breaker is rated up to 63A; the relay is marked at 60A maximum.
    [BL602] BL602 PTBLU-W WiFi Module Pinout and Specs in EARU EAKCB-EWE-M Circuit Breaker
    The rest of the construction looks very solid and easily capable of handling 60 amps.

    [BL602] BL602 PTBLU-W WiFi Module Pinout and Specs in EARU EAKCB-EWE-M Circuit Breaker

    Apparently these devices previously used a PSF-B wifi module. This one has a wifi module PTBLU-W based on the BL602. The module is mounted on a circuit board labelled YK-DPN-T-V1-1 which is dated 2023-6-6. I could not find any specs on the internet for the wifi module.
    Close-up view of the main PCB of the EARU EAKCB-EWE-M circuit breaker showing labeled GPIO pins of the PTBLU-W wifi module.
    The power supply has no transformer, so the module should never be powered by mains voltage while testing and measuring signals and voltages on the circuit board.

    The EAKCB-EWE-M provides a BL0942 chip for energy monitoring. Here's pictures of the other chips on the back side of the main circuit board. You can read the markings for just about every chip in one photo or the other.
    [BL602] BL602 PTBLU-W WiFi Module Pinout and Specs in EARU EAKCB-EWE-M Circuit Breaker
    Close-up view of the open PTBLU-W wifi module with visible BL602 chip on the EAKCB-EWE-M device's circuit board.

    To inspect the PTBLU-W wifi module, you can bend one corner of the metal shield, but the only thing to see is the BL602 chip marking (but barely visible). To do more investigation, it is necessary to remove the metal shield. If you don't have a hot air gun, you can (permanently) remove the metal shielding with a pair of pliers.
    View of the PTBLU-W wifi module with the metal shield removed, exposing the BL602 chip markings and pin layout on the PCB.

    With some work, it was possible to trace the connection for every GPIO pin for the BL602. The photo below shows the GPIOs for the 21 pins of the wifi module. There seem to be 3 extra module pins. I don't have a hot-air tool to remove the wifi module so I wasn't able to inspect or test the backside of the module.

    Close-up of a printed circuit board with a mounted PTBLU-W wifi module, visible pins and electronic components.

    The main circuit board only uses 10 of the wifi module pins 5, 11, 12, 13, 14, 15, 16, 19, 20, 21. These are enough to control all the functions of the EAKCB-EWE-M, plus one extra pin that I don't know the function (pin 5 - GPIO 22). The wifi pin mapping is:
    Pin 14 = 3V3
    Pin 13 = Gnd
    Pin 19 = Red LED, relay On/Off (active low) = GPIO 1
    Pin 20 = Blue LED, wifi status (active low) = GPIO 5
    Pin 21 = Push button switch (On/Off, active low ) = GPIO 4
    Pin 11, 12 = Bi-stable relay control = GPIO 20 (Set pulse) and GPIO 21 (Reset pulse)
    Pin 15, 16 = UART TX/RX connecting to BL0942 energy monitoring (GPIO 16, GPIO 7)
    Pin 5 = ??? 200K ohm resistor to 3V3 ??? (GPIO 22)

    There's an forum posting on how to configure the bi-stable relay in OpenBK; you may have to search further to get all the details for using BridgeFWD and BridgeREV.
    https://github.com/openshwprojects/OpenBK7231T_App/issues/667

    Note that you need to browse to 192.168.169.1 to access the starting OpenBK web page when the BL602 is in AP mode (with other chips, the starting web page is 192.168.4.1).

    There's another posting about issues with OpenBK releases >=1.18.95 for the BL602 when activating the UART too soon after booting; a 10 second delay is recommended in the posting. https://www.elektroda.com/rtvforum/topic4127126.html

    Please add to that last posting if you find other devices using the PTBLU-W wifi module, or find a simpler solution to activating the UART on a BL602.

    MANY THANKS to everyone for their super-quick replies and support for this newbie! :-)

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    About Author
    ProfAnderson
    Level 4  
    Offline 
    ProfAnderson wrote 14 posts with rating 10, helped 2 times. Been with us since 2025 year.
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  • #2 21598551
    szymon122
    Level 38  
    What in this module acts as a current measurement?
  • #3 21598597
    p.kaczmarek2
    Moderator Smart Home
    This information is already included in the description - BL0942 connected via UART. Classic. I have also seen it connected via SPI to the CBU a few times, but much less often. In addition to the BL0942, I also encounter the BL0937 frequently.
    A board with a BL0942 chip connected via UART interface to wires. BL0942 chip connected via UART on a circuit board, visible pins and wiring. .
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  • #4 21599379
    p.kaczmarek2
    Moderator Smart Home
    @ProfAnderson can you also post template as full JSON text from the Web App?
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  • #5 21600027
    ProfAnderson
    Level 4  
    Below is the template I'm currently using. Please note that I've decided to use the scripting method to toggle the bi-stable relay rather than use BridgeFWD + BridgeREV pin roles.
    P.S. The LED for power status is active low. Because it's red, I use it as a regular LED so that it's On when the power is Off (i.e. Red = problem! No light = all OK)


    Script:
    
    alias tick_setter backlog SetPinRole 20 AlwaysHigh; addRepeatingEvent 1 1 SetPinRole 20 AlwaysLow
    alias tick_zeroer backlog SetPinRole 21 AlwaysHigh; addRepeatingEvent 1 1 SetPinRole 21 AlwaysLow
    addChangeHandler Channel0 == 1 tick_setter
    addChangeHandler Channel0 == 0 tick_zeroer
    


    Template:
    
    {
      "vendor": "EARU",
      "bDetailed": "0",
      "name": "WiFi Smart Circuit Breaker 1P+N",
      "model": "EAKCB-EWE-M",
      "chip": "BL602",
      "board": "PTBLU-W mounted on YK-DPN-T-V1-1",
      "flags": "1024",
      "keywords": [
        "PTBLU-W",
        "Current Monitoring",
        "Energy Metering"
      ],
      "pins": {
        "1": "LED;0",
        "4": "Btn;0",
        "5": "WifiLED_n;0",
        "20": "AlwaysLow;0",
        "21": "AlwaysLow;0"
      },
      "command": "",
      "image": "https://obrazki.elektroda.pl/5083588700_1751735837_thumb.jpg",
      "wiki": "https://www.elektroda.com/rtvforum/viewtopic.php?p=21598551"
    }
    
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  • #6 21600032
    p.kaczmarek2
    Moderator Smart Home
    This script will work, but I suggest you to move to channels. Declare dummy channels, like channel 2 and 3, and use setChannel 2 1 or 0, etc.

    This is because setting pin role will save it to flash, so you will wear out flash that way, and setting channel value does not have to flash.
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  • #7 21600039
    ProfAnderson
    Level 4  
    >>21600032 Ahh yes! That's an excellent tip. :-)
    I'll rewrite the script today or tomorrow and post it here.
  • #8 21602677
    szymon122
    Level 38  
    p.kaczmarek2 wrote:
    This information is already included in the description - BL0942 connected via UART.
    .
    I have defined the question a bit badly.
    Does the 63A go through a measurement resistor? A current transformer? That's a bit more than the 16A found in sockets that measure energy consumption.
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  • #9 21602862
    ProfAnderson
    Level 4  
    >>21602677 The 63A goes through a current transformer. Also, other parts in the current path are very solid and heavy. I think there should be no problem carrying 40A without any heating. Going to 50A or 63A might start to cause some heating internally.
  • #10 21602942
    p.kaczmarek2
    Moderator Smart Home
    In the picture I see two two-pin connectors, probably one is from the relay and the other is from the current transformer.
    Helpful post? Buy me a coffee.
  • #11 21603398
    ProfAnderson
    Level 4  
    I've added another picture in the original description (just after "The rest of the construction looks very solid and easily capable of handling 60 amps.")
    It shows two 2-pin connectors on the left side, for the current transformer and for the relay. There's also a 2-pin connector on the right for the mains voltage (e.g. 240V).
    I hope this helps.
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Topic summary

The EARU EAKCB-EWE-M circuit breaker, rated up to 63A with a relay marked for 60A maximum, features a solid construction suitable for high current applications. The device includes a WiFi module PTBLU-W based on the BL602 chip, mounted on a YK-DPN-T-V1-1 circuit board dated 2023-06-06. This module replaces the previously used PSF-B WiFi module. The circuit breaker casing is secured by six rivets that can be drilled out for access. The power supply design lacks a transformer, indicating the WiFi module should not be powered directly from mains voltage. Detailed pinouts and internal images are available, but official specifications for the PTBLU-W module are not found online.
Summary generated by the language model.
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