Emergency lighting relays in Illinois buildings are installed to bring an emergency fixture to full brightness when normal power is lost, regardless of the position of any switch or dimmer. While normal power is present, the fixture behaves like any other light. Functional Devices, Inc. manufactures UL924-listed emergency lighting relays, including the ESR series used in automatic load control and bypass/shunt applications.
Source Emergency Lighting Relays in Illinois
Functional Devices manufactures the ESR series of UL924-listed emergency lighting relays. To specify a device, browse the emergency lighting control lineup or find an authorized Functional Devices distributor in Illinois.
What an Automatic Load Control Relay Does
An automatic load control relay (ALCR) sits between normal lighting controls and an emergency fixture. When normal power is present, the relay coil is energized and the emergency fixture will switch with the surrounding normal lighting. When normal power drops out, the coil de-energizes and the normally closed contact, held open while the coil was energized, falls closed. The fixture is fed from the emergency source and is brought to full brightness, regardless of the state of the switch or controller at the time.
Under this arrangement, the emergency fixture is included in everyday lighting control rather than left on continuously. The transfer in an outage is not dependent on any command from a control system; it occurs when the relay de-energizes.
ALCR or Bypass/Shunt Relay
The two device types cover different control situations.
Automatic Load Control
Models such as the ESRN-U and ESRB switch an emergency fixture with the normal lighting surrounding it, and override both switching and 0–10 Vdc dimming upon loss of normal power. An ALCR is the correct device when an emergency fixture must follow normal lighting controls during non-emergency operation.
Bypass/Shunt
Models such as the ESR2401B and ESR2402B bypass a local switch upon loss of normal power. A bypass/shunt relay is the correct device when the only requirement is that a switched circuit come on in an outage, and it does not need to switch or dim with the surrounding lighting under non-emergency circumstances.
The ESR Series
- The ESRN-U is a 20 A SPST automatic load control relay with a universal 120–277 Vac input, 0–10 Vdc dimmer override, and a dry contact fire alarm interface. It includes a local test button, LED status indicators, and a remote test input. is a 20 A SPDT automatic load control relay with a universal 120–277 Vac input, 0–10 Vdc / DALI dimmer override, and a dry contact fire alarm interface. It includes a local test button, LED status indicators, and a remote test input
- The ESRB carries a similar feature set and mounts inside the ballast channel, which suits retrofit work and fixtures with no room for an external enclosure.
- The ESRLBC is housed in a slim enclosure sized for linear lighting.
- The ESR2401B and ESR2402B are 20 A bypass/shunt relays for switched circuits that must come on when normal power is lost.
What UL924 Means
UL924 is the product standard for emergency lighting and power equipment. A UL924 listing means the device has been tested to that standard's requirements for transferring an emergency load on loss of normal power. On a relay, the listing is a product attribute: it identifies the device as suitable for emergency lighting control, the way a contact rating identifies what it can switch.
Frequently Asked Questions About Emergency Lighting Relays
What does an emergency lighting relay do when power fails?
During normal operation, the relay coil is energized by normal power, which holds the normally closed contact open. When normal power is lost, the coil de-energizes and the contact falls closed; the emergency fixture is then fed from the emergency source at full brightness. No command from a controller is involved.
What is the difference between an ALCR and a bypass/shunt relay?
An ALCR lets an emergency fixture follow the normal lighting controls, including dimming, and overrides them all upon loss of power. A bypass/shunt relay only bypasses a local switch in an outage. The ALCR is the device when the emergency fixture is part of the everyday lighting scene.
Can an emergency lighting relay override a 0–10 V dimmer?
Yes. The ESRN and ESRB include a 0–10 Vdc dimmer override that drives an emergency fixture to full brightness on loss of normal power.
How is an emergency lighting relay tested?
The ESRN includes a local test button and a remote test input. LED indicators on the housing show normal power, emergency power, and load status during the test.
Where can I buy ESR series relays in Illinois?
The ESR series is stocked by authorized Functional Devices distributors across Illinois. A distributor can confirm availability of a specific model and advise on ALCR versus bypass/shunt selection for your specific application.
