UL924 Relays with Fire Alarm Input

Tech Tuesday UL924 Relays with Fire Alarm Input

Functional Devices, Inc. manufactures a wide range of UL924 Listed products. These devices provide a means for compliance to code requirements for emergency egress lighting. They can be used to bypass (shunt) a switch or override switching and dimming controls. Another feature often overlooked on several of our ESR products is the Dry Contact Input, which can be used for a remote test input. It can also be connected to a fire alarm panel to meet NFPA 101 requirements for new installations

UL924 Relays We Offer

The specific products we offer in our ESR line that have the Dry Contact Input are:

All the models listed above can be used to, “automatically energize the controlled lights upon loss of normal power,” to comply with NFPA Each also have an auxiliary contact which can be used to override 0-10V dimming controls, and they all have the Dry Contact Input. The wire diagram for the ESRN, shown below, shows this input in the lower-right.

ESRN Diagram

Dry Contact Input Function

This connection is meant to wire to a Normally Open (N/O) contact like our ESRTB or a Fire Alarm panel. The benefit of accepting a N/O contact is that many outputs can wire to it in parallel. If any of those inputs close, the device will behave as though Utility Power was lost. It will bypass the Wall Switch shown in the diagram, and it will override 0-10V dimming wired through Terminal 1 and Terminal 2. When this contact is open, the device performs its usual function of monitoring for a loss of Utility Power.

Added Benefit

A bonus to the Dry Contact Input on these products is that the connection is UL Class 2 rated. The benefit is that the NEC does not require boxes or other enclosures for Class 2 splices and terminations. The NEC also does not require a Class 2 circuit to be installed in a raceway. Both exceptions can save time and money on an installation. Any of the models in the above list can be used to comply with NFPA, which states, “In new installations, the lighting control device is activated by activation of the building fire alarm system, if provided.”

Contact Us

If you are interested in our lighting products, contact our sales department or your local lighting representative. If you have any questions about our products or an application you have, call our technical support, or send us an email. We are always happy to help!

Henry Smith
Henry Smith

Henry Smith is a design engineer at Functional Devices, Inc. He has a BS EET obtained from Purdue University in 2014 and a lifelong interest in electronics. As an engineer at Functional Devices, he gets to provide Technical Support to our customers, from distributors to specifying engineers and installers.

Henry enjoys providing tech support, as it allows our company to assist at every level of our product’s lifecycle and exposes us to interesting and unique applications. While not every technical question is unique, even answering a simple question or providing someone with the information in a timely manner can go a long way to helping him or her meet a deadline.

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