Can a Power over Ethernet system support emergency lighting?

This question was answered by Jonathan Bell, commercial director of Liteplan Limited.

The idea of a Power over Ethernet (PoE) system appears to be far more complicated than the reality. A great deal of research and development work has been carried out behind the scenes to develop installer-friendly systems. The main difference between a traditional mains system and a PoE system is the operating voltage.

A PoE system distributes its power at a nominal 48v DC and typically connects to each luminaire via an RJ45 connector. The UK emergency lighting companies are already set up for this and have been for some time.

Explainer: an RJ45 connector is the typical plug+socket arrangement that we see on our computers for wired connections to internet routers and local area networks (LAN).

 

There are three main ways in which emergency lighting can be integrated into a PoE system. 

1. Convert a standard PoE-enabled luminaire to an emergency supply using a PoE-specific emergency conversion kit, together with a local battery. 

2. Use standalone emergency LEDs that, again, would be specific to a PoE system and would operate with local or, commonly, integral batteries. 

3. Use a small rack-mounted lithium iron phosphate central battery that would feed power to individual emergency LEDs in the event of a power failure. 

 

All of these options are commercially available. Liteplan has been working on a number of schemes with Prolojik’s Light Matrix PoE system. One thing to remember: the idea of PoE is not only to consume less power, but to be simple to install and maintain. We have certainly found that to be the case. As with any new technology, the way in which these systems are provided and installed is ever evolving. Be aware that, at this time, there is no specific standard covering PoE for emergency lighting.

Important note: if you are connecting a PoE-enabled luminaire to a separate battery, whether it be mounted adjacent to the luminaire or a central battery, that cabling MUST be fire-rated to ensure that power to the emergency lighting cannot be compromised.