Lighting systems often require switching capabilities that go beyond what a standard wall switch can provide. Large banks of fixtures, mixed lamp types, and integration with building automation demand components that can handle higher current loads while still being controlled by low-voltage signals. This is where general purpose relays play an essential role, providing electrical isolation, reliable switching, and the flexibility needed for modern lighting control.
This blog will explore how our RIB® (Relay-In-a-Box) general purpose relays function in lighting controls and what makes them effective. By understanding their technical capabilities and practical benefits, contractors, engineers, and facility managers can ensure safer, more efficient, and more reliable lighting systems.
Functional Devices has been a trusted manufacturer of relays and building automation components for over five decades, providing reliable solutions for lighting, HVAC, and general control applications. For help selecting the right general purpose RIB relay for your project, contact our support team.
What Is a General Purpose Relay?
Before we get into RIB relays specifically, we need to answer the question, “What even is a general purpose relay?”
A general purpose relay is an electrically operated switch designed to control one or more circuits by using a low-power signal to open or close higher-power contacts. It consists of a coil that, when energized, creates a magnetic field to move internal contacts, allowing it to safely isolate and control loads such as motors, fans, pumps, or lighting circuits.
Unlike specialized relays tailored to narrow applications, general purpose relays are built for versatility, with options for different coil voltages, contact ratings, and pole configurations (SPDT, DPDT, etc.). This flexibility makes them suitable for a wide range of control tasks, especially where electrical isolation, reliable switching, and adaptability are required.
RIB General Purpose Relays & Their Applications
Our RIB general purpose relays are designed to simplify applications. With prepackaged enclosures, multiple coil voltage options, and a wide range of contact ratings, these UL-listed devices eliminate the need for additional components or complicated wiring. They can handle the inrush current associated with LED drivers or HID ballasts, manage switching for both single and multiple circuits, and integrate seamlessly with sensors, timers, or automation controllers.
Unlike open-frame relays that require separate mounting, sockets, and enclosures, RIB relays come ready to wire with built-in housings, flying leads, and clearly labeled connections. They are available in multiple coil voltage options, such as 10–30 VAC/DC, 24 VAC/DC, 120 VAC, and 208–277 VAC, allowing them to interface seamlessly with a variety of control signals. With contact ratings ranging from 10 to 30 Amps and configurations like SPDT and DPDT, RIB relays are versatile enough to handle both light- and heavy-duty loads.
These relays are widely used across different applications where safe and reliable switching is required. In lighting control, RIB relays can switch banks of LED or fluorescent fixtures, integrate with occupancy sensors, or work with building automation systems to reduce energy use. In HVAC, they can control fans, pumps, and compressors, while in general building automation they are often used to interface low-voltage control signals with higher-voltage equipment.
Specialty models also include features such as BACnet compatibility or dry contact inputs, expanding their usefulness in smart building applications. This adaptability makes RIB general purpose relays a go-to solution for contractors and engineers who need dependable, ready-to-install relays for a wide range of functions.
Use Cases: RIB General Relays in the Field
In lighting control systems, general purpose relays are commonly used in a variety of scenarios. Let’s explore some examples of RIB relays in action.
Bathroom Fan
In a bathroom, you may have a light switch controlling 277V lights and a 120V fan that you would like to hook up to the light switch. Time to install a transformer, right? Actually, no! You just need a general purpose relay. What you need is an LR2402B2G. It is a 20A relay with a 208-277V coil voltage. Connect the coil to the 277V light switch, wire up the contacts to the 120V fan, and you're done.
Options for Controlled Receptacles
Many of our customers have LED strips or other types of lights that turn on when plugged in. Functional Devices’ customers, being the intelligent and good-looking bunch they are, think, "How can I remotely control this electrical outlet?" Well, as luck would have it, we offer a general purpose relay that can generally meet this purpose. Take a look at the LR2401B2G.
The signal turning on and off the LR2401B2G could be from a variety of sources. A lighting ballast, light switch, or even a third component. The LR2401B2G and LR2402B2G are perfect devices for when the lighting world just needs a thing to turn on another thing.
Both models have two poles, which are completely isolated, so you could switch two loads at once. One pole is normally open while the other is normally closed, in case you want to switch on a device with another turned off. The contacts are rated for 16A at 277V Electronic Ballast, which means they can be used to turn on LED lights without worrying about inrush current. The coil voltage even has a 24V option if you're trying to turn on a high-voltage device with a low-voltage signal.
The Right Relay for the Job
Functional Devices' general purpose relays are so good, the competition might as well be selling First Lieutenant purpose relays (OK, we admit we’re a little biased). With proven durability, versatile applications, and the proprietary preassembled design, these relays are built to handle the demands of modern lighting control systems. When the job calls for reliable switching, why settle for anything less than a battle-tested General?
Whether you’re retrofitting an existing system or designing new construction, Functional Devices’ relays offer the perfect combination of flexibility, performance, and ease of installation, so you can keep your projects on schedule and your customers happy. Browse our options and reach out to us if you need help in your selection.
About Functional Devices, Inc.
Confidence and Peace of Mind in Every Box
At Functional Devices, Inc., we have been designing and manufacturing high-quality electronic components in the USA since 1969. Our mission is simple: to enhance lives in buildings and beyond by delivering reliable, innovative solutions for the building automation industry. Our product lineup includes RIB® relays, current sensors, power controls, power supplies, transformers, lighting controls, and more—each designed to meet the highest industry standards.
We test 100% of our assembled products, ensuring an exceptionally low failure rate—less than 1 in 16,000 in the field. This commitment to excellence means you get products that perform reliably, reducing downtime and increasing efficiency. With every Functional Devices product, you receive more than just a component—you gain confidence and peace of mind knowing your systems are built on trusted, field-proven technology.