PZEM-004T v3 AC energy meter (UART) with ESP32

Supply 5 V Bus GPIO Measures voltage, current, power, energy, frequency, power factor

Pins and ESP32 wiring

Pin	Role	ESP32 pin	Notes
5V	Power	VIN	TTL side supply. Isolated from mains by optocouplers
RX	Input (the ESP32 drives it)	D25	UART: the meter receives data here. Connect to an ESP32 TX pin (9600 baud, Modbus RTU)
TX	Output (the part drives it)	D26	UART: the meter sends here. Idles at the 5 V supply: add a divider before the ESP32 RX pin
GND	Ground	GND
L	Not wired to the ESP32	—	MAINS 230 V! Only a qualified person connects this. Never to the ESP32
N	Not wired to the ESP32	—	MAINS 230 V! Only a qualified person connects this. Never to the ESP32
CT+	Not wired to the ESP32	—	Current transformer lead (100 A version). The measured wire passes through the CT
CT-	Not wired to the ESP32	—	Current transformer lead (100 A version)

Suggested wiring for the 30-pin ESP32 DevKit, avoiding flash, input-only and strapping pins. BoardPilot checks it for you as you wire.

This module is sold for 5 V. Its outputs may be 5 V: use a level shifter or a voltage divider on ESP32 inputs.

Peacefair PZEM-004T V3.0 user manual, Measures voltage 80 to 260 V, current, power, energy, frequency, power factor
Peacefair PZEM-004T V3.0 user manual, TTL serial 9600 baud, Modbus-RTU; TTL side powered with 5 V

Part data: CC BY 4.0, free to reuse with credit to BoardPilot.