Five Ways the RIBU1C Can Replace Multiple Devices

On a multi-building or multi-panel job, relay count is where both the parts list and the callback list can really grow. Every control point that needs a different coil voltage or a different switching sense is another relay to stock, spec, and wire.

Functional Devices, Inc. builds the RIBU1C—a pre-wired, UL Listed RIB® (Relay-In-a-Box®) device—in the United States. The RIBU1C is able to do the work of several different parts on a controls job because of its simplicity, its durability, its diverse switching capabilities, and its compatibility with multiple power sources.

Read on to learn the five main ways that integrators use the RIBU1C to simplify building automation jobs.

1. Interposing Between a Controller and a Line-Voltage Load

The RIBU1C’s base use is isolation. Because a building automation system (BAS) or programmable controller output switches at low voltage and cannot drive a line-voltage load directly, the RIBU1C sits between them—its coil takes the control signal, its contacts switch the load—so the controller never comes into direct contact with line voltage. One relay can be used for fan coils, small lighting loads, and solenoid valves, up to its 10 Amp rating. For applications above 10 Amps, use the RIB2401B (20 Amp SPDT) instead.

2. Piloting a Contactor or Power Relay

When a load is larger than a pilot relay is able to switch—a large motor, for example, a bank of lighting, or a heater—it should be switched by a contactor, not by the RIBU1C directly. A contactor closes its heavy power contacts and switches a load when its own coil is energized. However, a building automation controller output usually cannot energize it directly: the coil often runs at a higher voltage than the controller can supply, and the current surge it draws can wear out a small controller output over repeated cycles.

This is where the RIBU1C becomes relevant. The controller drives the RIBU1C coil; the RIBU1C contacts, isolated from that coil and rated for the inrush, energize the contactor coil; the contactor switches the load. The controller only ever drives the small relay, and one RIBU1C bridges any control voltage to any contactor-coil voltage.

This is also the correct approach for motor loads. The relay handles on-and-off switching, while overload protection stays with the starter or the motor’s thermal protector. A RIB relay does not protect a motor from overload.

3. Covering Normally-Open or Normally-Closed Logic With One Relay

The RIBU1C’s SPDT contacts include both normally-open and normally-closed outputs, so one relay can cover either switching direction depending on how it’s wired. An integrator does not need to stock a separate N/O and N/C part; one RIBU1C covers both. Its dry contacts also switch high voltage, low voltage, or a dry signal, so the same relay works whether the downstream device is a line-voltage load or a low-voltage input on another controller.

4. Standardizing on One RIBU1C Coil Across the Job

The RIBU1C coil accepts 10-30 Vac/dc or 120 Vac, so one part works whether a given controller outputs 24 Vac, 24 Vdc, or line voltage. On a job with mixed controllers, that means the RIBU1C can replace the two or three voltage-specific relays an integrator would otherwise stock.

5. Replacing a Loose Relay Assembly With One RIBU1C

Specified as discrete parts, a single control point is a relay, a socket, a mounting base, surge suppression, and an enclosure: five separate items to order, assemble, and mount. The RIBU1C is all of that in one pre-wired device. Across a job with dozens of control points, that removes most of the panel assembly a loose-relay approach would require.

Frequently Asked Questions About RIBU1C Applications