When it comes to control applications, some of Functional Devices’ “Relay-In-a-Box®” (RIB) relays stand out for their versatility and reliability across a wide range of installations. These relays are not defined by a single, narrow use case, but instead, are designed to handle multiple functions, making them highly adaptable in the field. Their universal appeal lies in their ability to interface with different control voltages, handle diverse load types, and provide dependable switching performance under varying conditions.
For technicians, engineers, and installers alike, these relays serve as go-to solutions when faced with unexpected challenges on the job site. Having a selection of universally applicable relays readily available can reduce downtime, simplify troubleshooting, and even eliminate the need for additional components. In this post, we’ve highlighted ten of the most broadly useful RIB relays available today!
Functional Devices has long been a trusted source for reliable, easy-to-use relays that meet the demands of real-world projects. To learn more about our RIB line or to get support in selecting the right relay for your application, contact our engineering team.
Updated for 2025
All of the relays featured in this list remain current offerings from Functional Devices and continue to be widely used in modern control applications. Core models such as the RIBU1C and RIB2401B are still industry staples, valued for their versatility, UL/CSA approvals, and long cycle life. Relays with specialized features, like DPDT contacts, multiple coil voltage options, or BACnet integration, are likewise still available and relevant in HVAC, automation, and custom control projects. This list remains accurate and applicable for 2025, making these relays dependable go-to solutions for technicians, installers, and engineers. For the most up-to-date specifications, visit the Functional Devices RIB Relay catalog.
1. RIBU1C
RIBU1C: This one is a no-brainer. With 10-30 Vac/dc or 120 Vac coil options and 10 Amp rated SPDT contacts, it's no wonder this relay can be used for anything from a Nest Doorbell to a Fountain Pump. The "U" in RIBU1C even stands for "Universal" and serves as the inspiration for the rest of this list.
2. RIB2401B
RIB2401B: This one is like RIBU1C's bigger brother. It's largely similar with 24 Vac/dc or 120Vac coil options and 20 Amp rated SPDT contacts. Useful in a lot of the same applications as the RIBU1C, this model, however, can handle larger loads thanks to its increased contact ratings. A RIBU1C can turn on a fan. From the same signal, a RIB2401B can turn on a much bigger fan. Besides that, they're really the same relay.
3. RIB2401D
RIB2401D: This one is the RIBU1C's cousin. Its coil voltage options and contact ratings are mostly the same as the RIBU1C's at 24 Vac/dc or 120 Vac and 10 Amps. The thing that sets this apart from the RIBU1C is the fact that it has DPDT contacts instead of SPDT, meaning you can control two different loads with the same signal. Overall, anything you can do with the RIBU1C, you can do with the RIB2401D.
4. RIB24P
RIB24P: If the RIB2401D is the RIBU1C's cousin, then that would make the RIB24P its... uncle? Actually, let’s abandon the RIB family tree before it gets any more confusing! This thing has got a 24 Vac/dc coil and 20 Amp rated DPDT contacts, meaning it can switch on two of almost anything from a 24V signal.
5. RIBU2C
RIBU2C: We've already talked about how great and universal the RIBU1C is. Now imagine having two of those in one box. That's exactly what the RIBU2C is. This relay shows up in a variety of unusual applications, but our favorite might be one involving a bathroom exhaust fan.
6. RIBTW2401B-BC
RIBTW2401B-BC: This relay at its bare bones is the same as the RIB2401B, so naturally it can do just about anything that the RIB2401B can do. What sets this relay apart is its BACnet communications and the addition of a binary input. There are many possibilities when used in a BACnet application.
7. RIB24P30
RIB24P30: This one makes it onto this list because of one key feature: contact size. Its DPDT contacts are 30 Amp rated, making it the beefiest relay we have. This relay can handle almost any load you would need a relay for. If you manage to have a load that's big enough to exceed this relay's contact ratings, then you no longer need a relay.
8. RIB01BDC
RIB01BDC: This relay is once again a lot like the RIB2401B. What makes it different is it sacrifices the 24 V coil for a dry contact input. From automated dust collection to irrigation systems to appliance garages, the applications for this model are extremely versatile.
9. RIB2421B
RIB2421B: Like the RIB24P30, this relay makes it onto this list because of a unique feature. Its coil has an option for 24 Vac/dc like many of the other relays on the list but has two additional coil options: 120 Vac and 208-277 Vac. Pair that with its 20 Amp rated SPDT contacts and you have a relay that can switch almost any load at almost any voltage.
10. RIBRL1S-NS
RIBRL1S-NS: Imagine the RIBU1C but packed in a super-convenient DIN rail mount housing. That's basically what the RIBRL1S-NS is. While excluding the 120 Vac coil option, it has a coil side override switch. This makes it super useful for any panel applications.
The Value of Universal RIB Relays
This list highlights ten of the most universal and versatile RIB relays available today. Whether it be coil voltage flexibility, higher contact ratings, DPDT configurations, or specialized communication capabilities, each model offers unique features that make them adaptable to a wide variety of applications. These relays are designed to save time in the field, reduce troubleshooting complexity, and provide dependable performance across industries ranging from HVAC to automation and general building controls.
While these ten relays represent some of the most common “go-to” solutions, the RIB product line as a whole is extensive and continues to evolve to meet modern requirements. Installers and engineers who keep a selection of these universal relays on hand are better prepared for unexpected situations during installation and service. For additional guidance in selecting the right relay for a specific project, the Functional Devices engineering team is available to provide expert support and product recommendations. Contact us today!