Emergency Lighting with Dimming Control

A few weeks ago, I wrote a blog post about two of our UL924 Emergency Lighting Bypass / Shunt Relays (models ESRB and ESRN). This week I want to focus on a specific application for them; one which shows up frequently. The ESRB and ESRN can be used in conjunction with a 0-10Vdc Dimming Control Panel and can control Emergency Lighting under normal conditions.

Under Normal Conditions, with the Lights ON

When the Lighting Control Module closes a single zone’s contact, the Normal Power feeds through to both the Normal Lighting loads as well as the ESRB/ESRN’s Switched Input. Even though the Normal/Emergency Lighting is being powered from the Emergency Panel, it is still controlled by the zone contact and 0-10Vdc signal on the controller. See image below for a wiring schematic:

Under Normal Conditions, with the Lights OFF

When the Lighting Control Module opens a single zone’s contact, the Normal Power stops at the open contact, and does not feeds voltage through to either the Normal Lighting loads or the ESRB/ESRN’s Switched Input. Even though the Normal/Emergency Lighting is being fed 0-10Vdc from the controller, the high voltage side of the load is broken by the ESRB/ESRN relay contact due to the lack of a control voltage on the Switched Input. See image below for a wiring schematic:

Under Normal Power Failure

When there is no Normal Power present, the Lighting Control Module cannot control either the zone contact or the ESRB/ESRN. The ESRB/ESRN notices the absence of Normal Power, and therefore passes the Emergency Power through the relay contact and out to the Normal/Emergency Lighting. Because there is 0V coming out of the controller, and because there is high voltage applied to the power input of the Emergency Lighting loads, the Normal/Emergency Lighting loads come on at full brightness. See image below for a wiring schematic:

Need more information on our full line UL924 Emergency Lighting Bypass / Shunt Relays? Give us a call or shoot us an email, and we’ll be happy to answer any of your questions.

About the Author

David Mackey is an Engineer for Functional Devices. He is a husband of one, a father of three, and a servant of Christ Jesus. David graduated from Purdue University with an Electrical Engineering Technology degree.

He enjoys working with his hands on things like woodworking, cars and, of course, electronics. He is 5' 13" and wears glasses, unless he wears contacts. He is also a self-made hundredaire.