Functional Devices RIB2401B Power Relay, 20 Amp SPDT, 24 Vac/dc/120 Vac Coil, NEMA 1 Housing

These are high quality manufactured relays! They work well. The only real issue with them is that they are hard to figure out which one you need for your application. They don't come with any documentation. The mfrs web site has some information, but read up on your application needs before choosing the model you need. There are many models to choose from. The only other thing to note is that some of the models do not engage immediately depending on the wiring of the circuit board in the box. I've seen some models with about a 1 sec delay, if this is important to you.

I'm using this to switch blower speeds in my older PSC blower furnace/AC depending on zoning calls, and it works perfect! Rock solid for nearly a year now.

Used this Functional Devices RIB2401B relay to have an Ecobee Lite control a kerosene heater in my workshop to prevent freezing. Setup was simple — installed in minutes, and it’s handling 20A with no issues. I set it to maintain 40°F by offsetting the temperature delta and only trigger when it’s 3° below set point. Now I have full remote control, and the heater cycles exactly as intended. If you want to add smart control to a traditional heater or other high-current device, this relay makes it easy, reliable, and safe.

I used to this to automate my humidifier using my (nest) thermostat. I worked for a good 5 years. It's fits on the side of my furnace with ease and was a great price. Recently I noticed that it was constantly running even when not commanded by the thermostat and had that burned electronic smell. I tore it apart and one of resistors appeared to have been overheated. So I ordered this replacement (exact same as before) and noticed that it was also constantly staying on. I discovered the signal wire was shorted to hot (24vac) somewhere in the thermostat's base circuit board. So I don't know if the relay failed and took out the thermostat base. Or if the thermostat failed and kept the relay engaged long enough to overheat. Chicken or the egg situation. The replacement one is again working great.

This was the missing piece for my home solar setup. I have an EG4 3000EHV-48 inverter connected to two eco-worthy 48v rack-mount batteries (purchased from Amazon.com) and some solar panels. The issue was that the inverter does not have an internal Neutral to Ground bonding relay. In simple English, when I tried running my devices on battery, the electrical supply was unstable, the LED lights started flickering, etc. After months of research I was able to determine that the missing N-G bonding relay was the issue and I after more research the Functional Devices RIB2401B relay kept coming up as the relay to get to peform the simple task of monitoring my AC power (power from the electrical grid) on my main panel and then if there is a power outage, it would simply connect the Neutral and Ground wires in my load panel (devices to be powered by battery if I lose power). This worked perfectly, and I am finally able to enjoy my solar investment.

Arrived earlier than promised and worked as expected. Good purchase!

Great design, easy to follow instructions. Red light when powered makes testing and triaging issues super easy from afar. Not a tiny devise, but not huge. Love the mounting holes, no bracket needed. Works AC and DC, NO and NC - very versatile. I used this for hooking up a nest to a thermostatically controlled pellet stove. Used a tiny wire under the baseboard to run the 24vAC signal from the Nest (needs a C wire for this to work) to this relay, which then controlles the 5vDC thermostat signal on the stove.

Well OK, it's not easy to get excited about a relay, but this one has worked perfectly for my application. I'm using it to switch speeds when controlling my 2-speed QuietCool ES-3100 whole house fan via my Alexa+SmartThings setup, in conjunction with two on/off Z-Wave switches (one switch controls power to the fan, the other selects Hi/Lo by using this relay). I know the 20 amp rating on this relay is overkill for the 670W fan motor, but I wanted to be prepared in case I want to up-size the fan in the future. I mounted this relay right onto the junction box that's part of the fan; a perfect fit. A lock nut is included with the relay for attaching through 1/2" openings on junction boxes. Very good quality product, highly recommended, with the connection diagram clearly marked on the unit itself.

Using this for my second stage of heat to control a 240v 4000 watt heater. No concerns with the current running through it, the unit works flawlessly. Like the multiple hook up and voltage options. Get this if you need for controlling your higher current loads.

This relay is a beast and works every time its triggered not like the lesser quality ones I've bought in the past.

Works as expected, very versatile

I used this relay along with a 24 volt transformer to replace a defective circuit board on my household central vac system. I would have given this a 5 star but I had a great deal of trouble understanding the electrical drawing as to how to correctly wire this unit up. The relay came only with an extremely basic imprint of internal and external wiring on one of its sides. It would have been very helpful if more wiring diagrams had been included in the package. After several plus hours of frustration I finally did figure out the meaning of the wiring diagram and wired my system successfully. It works great!

Fit on junction box, works perfectly, no busing noise, and also n/o and n/c function, great value for the price