Zigbee Relay with Energy Monitoring for High Power Appliances

On my AliExpress Reviews channel, I recently disassembled and reviewed an interesting Zigbee module with an 80A CT Clamp for Energy Monitoring. It’s currently deployed in my server room, clamping the live wire of my main power strip feeding power to the devices I’ve setup there. It operates okay, but is used solely for power monitoring and doesn’t have a relay for controlling devices.

Digging through AliExpress a few weeks backs, I found an interesting 30A Zigbee Smart Switch with Energy Monitoring sold by some company named Colorock so I decided to buy one for testing. It’s intended for high power appliances, such as large fridges, heaters, tumble dryers etc.

As usual, I will teardown the device, integrate it in Home Assistant and do some tests to verify it’s capabilities. This relay is relatively cheap, going for $13.5 on AliExpress and a bit more on some Amazon stores.

Technical Specification

• Model: CR-MNZ1
• Maximum Load: 30A
• Voltage: 90-250V AC
• Product Size: 88x60x30mm
• Communication: ZigBee3.0
• Power On State: On/Off/Restore
• Energy Monitoring: Voltage (V), Current (A), Power (W)

Disassembly

This relay came packaged in cheap cardboard box with a manual and the device inside. Package was smushed, but the device intact.

The Colorock 30A relay has 4 terminals at the bottom, L-N In and L-N Out, as simple as they come. These are high quality screw terminals and are larger than you normally would encounter in these types of switches. The body of the device is round with a hole at the top for screw mounting.

On the backside of the case, you can see 3 screws holding the front and back together. Sticking out of the side is the pairing button and an indicator LED. This 30A relay is a bit larger than your usual smart switch, yet it’s still within reasonable boundaries.

Getting inside was fairly easy. My first observation is the PCB is very neat, clean and professionally done. It’s shape is purposefully cut to fit the round case of this 30A relay.

Flipping over the PCB, I can understand why this smart switch is larger than most. That relay is HUGE. On top of that, they installed a 40A version instead of 30A like advertised. It was manufactured by some Chinese company out of Shenzhen, and even though on paper it sound superb it’s actual operation will of course need to be verified.

Zigbee communication is handled by a Tuya ZT2S Module [Datasheet], which contains a low-power 32-bit CPU, 1024-KB flash memory, 64-KB RAM, and rich peripherals. The device operates as a Zigbee router with this module.

Installation

Installing the Colorock 30A Zigbee Smart Relay is as simple as it can be:

• Connect your AC input L-wire to the L-In terminal
• Connect your AC input N-wire to the N-In terminal
• Connect your output L-wire to the L-Out terminal
• Connect your output N-wire to the N-out terminal

For the completely inexperienced, there is a simple diagram in the manual that you can follow.

Home Assistant Integration

The Colorock 30A Zigbee Relay is officially supported in both Zigbee2MQTT and ZHA. To pair the device to your coordinator, press and hold the small button on the side for ~7 seconds until the LED starts flashing.

Zigbee2MQTT

Once paired to Zigbee2MQTT, the Colorock 30A is identified as Model TS0001_power and Manufacturer _TZ3000_tgddllx4. This relay reuses the Tuya TS0001 herdsman converter, so the photo is from a Tuya 1 Gang Switch.

It exposes a bunch of entities in Home Assistant through Zigbee2MQTT:

• switch: Toggle On/Off
• power: reading in W
• current: reading in A
• voltage: reading in V
• energy: Sum of consumed energy in kWh
• switch_type: Toggle, State and Momentary
• power_outage_memory: Return to last state in case of power failure
• linkquality: Signal Quality in LQI

Considering this specific Herdsman Converter is reused from a generic Tuya 1 Gang Switch, the switch_type setting has no effect on the Colorock 30A relay. It stays in toggle mode no matter which type you set it too.

If needed, energy values can be calibrated from the Zigbee2MQTT Settings (specific) menu as well as set the decimal precision of the measurements:

ZHA

Pairing the device to ZHA, it’s identified as model TS0001 with manufacturer _TZ3000_tgddllx4 with a custom quirk pre-applied, labelled tuya.ts000x.Switch_1G_Metering. Device is correctly identified as a router.

Some settings are incorrectly loaded together with the quirk, such as the Backlight mode setting. This is used on the TS0001 1 Gang Tuya switch as an indicator, which this relay doesn’t have. The main toggle entity is also added in the light domain instead of switch, but this can be easily changed if needed.

I verified the Power on state settings works as intended, either set to On, Off or LastState.

Usage and Testing

To verify the real-life usage of this Colorock 30A Relay, I decided to connect it to an AC I have deployed in my office:

The basic equation for calculating power is P=V x I (W=VxA), which gives us 234v x 5.79a = 1354.86w. The reported value in Zigbee2MQTT is 1352w, which is a difference of less than 0.25%, incredibly accurate for a device of this type. If you need to calibrate the input voltage or current, you can do so in the Setting (specific) menu.

I had nothing in my office to push this relay to 30A, let alone 40A to match it’s installed relay. I managed to push it to a maximum of about 17A, by connecting a bunch of different things on a power strip. I opened up the plug and wired the strip directly to the relay, I didn’t even fully detach the plug from the wires. Here’s a photo (ugly, but works for testing purposes):

I plugged in the AC again, my high end PC with monitor, a printer, and a hot water dispenser that I had in the office. I made sure everything was turned on, and a benchmarking job (Geekbench) running on the PC:

It gave me a reading of 3986w, which is 234v x 17.05a = 3989.7w again pretty close, an offset of 0.1%. The readings was naturally jumping up and down, as the devices drew different energy amounts in a given moment, but calculating the power draw a couple of times gave me about the same offset.

Verdict

This Colorock 30A Relay has kind of a specific use case: Monitor and Control High Power appliances or machines, such as tumble dryers, large freezers or fridges, heaters, anything within that 30A limit. They installed a 40A relay inside this device, possibly because of two reasons I can think of:

• For users intending to push the limits of the relay to 30A (highly unlikely), there is a 10A overhead for which the user is not aware of and can operate the device safely
• Supplying issues, 40A were easier or cheaper to get

In reality, the reason doesn’t matter as 40A is nice to have. When using the device, the relay is much louder than usual 10A or 16A relays you encounter in smart switches. In my experience, this is an indicator of good quality and that click gives me a certain peace of mind.

As far as Zigbee connectivity goes, It operated without issues in my two testing setups. Right now it’s connected to Conbee II + Zigbee2MQTT, reporting at around 250-255 LQI.

Buy

You can buy the Colorock 30A Relay on AliExpress and some Amazon stores. This relay is also available in black, as a Wi-Fi or RF variant. The ecosystem for the Wi-Fi version is Tuya Smart Life, so I suggest going for the Zigbee version.