Review on ⚡ Reliable Emerson 380 Relay Volt Coil for Efficient Electrical Control by Brandon Barrett

This little relay is cheap but good quality. I used this along with a 24v wire transformer to power my millivolt kettle. Since my current system didn't have a C wire, just Rh/W wires to turn on the heater, I couldn't just plug my Nest in. After some research it seemed to me that the safest way to add a 24V power supply would be to use a transformer and a relay. Some manuals claim that connecting two transformer wires to the Nest's C and Rc terminals will work (which it will), but you run the risk of the Nest sending 24V power to your millivolt system, which won't work. To get around this I hooked up my transformer then ran the Rh wire to the thermostat and the W wire from the thermostat to this relay on the control end and then back to the transformer to complete the circuit. Then I just connected the red and white wires coming from my boiler to the control side of the relay. The possibility of two different voltages crossing and damaging my old heating system has been completely eliminated. I also ran extra wire for the C and Rc connectors to ensure continuous power, but this isn't necessary in this setup, just for reassurance. Now that it's getting cold this relay has been tested with no problems. The outlet turns on to generate heat and the relay gives a reliable click with instantaneous heating. Note, however, that this is a physical relay, so the clicking is clearly audible. If you don't want to hear it, put it somewhere far away. If you're not a fan, you can find a solid state relay that should do the same.