Should IP cameras be UL Listed?

Occasionally, customers ask me about "Underwriters Laboratories"-listed IP cameras (devices tested and approved by the nonprofit product safety organization). They wonder whether or not a non-UL-listed IP camera can cause a life-safety issue during any life-threatening emergency. All IP cameras should be powered up using a UL-listed power supply, whether a POE switch or a power injector. I am not sure if you can even find a non-UL-listed POE switch and injector, so for all practical purposes, it should be a non-issue. Since all Power Over Ethernet IP cameras lack their own power supplies, they wouldn't be listed with UL. If someone has a good reason to use a non-UL-listed camera, I would love to hear it.

Power over Ethernet for IP Surveillance Systems

You've probably seen advertisements for POE switches and POE-compatible IP cameras. Here's what this all means, at least as far as IP cameras and other devices that are installed over an Ethernet network.

POE is an established technology that provides low-voltage direct current (DC) power delivery to network devices over the same wires that currently carry data. This means you can now run only one cable and still be able to both power the device and transfer data. The specifications come from the IEEE standard 802.af. This allows the powering device to use a voltage from 36-57 VCD. The most common voltage found is 48 volts.

Here are the different classes of POE devices.
Class Usage Maximum Power Levels at Input of Powered Device [Watt]
0 Default 0.44 - 12.94
1 Optional 0.44 - 3.84
2 Optional 3.84 - 6.49
3 Optional 6.49 - 12.95
4 Reserved (PSEs classify as Class 0)

One of the problems with CCTV IP cameras is that sometimes a heater, blower and a PTZ device are needed in some applications. The current standard only provides a maximum of 15.4 watts. Most PTZ devices and heaters and blower exceed this maximum.

There is good news on the horizon. A future standard, commonly referred to as POE+, is being developed by the IEEE 802.3at task force. There is still debate on the maximum wattage, but it is typically between 24 and 30 watts. This will allow many manufacturers to design their PTZ cameras with heaters and blowers around this new standard and still only run one cable to the camera location from the network switch.

Designing Access Control

In a traditional wired access control deployment, a door controller is connected back to either a (non-IP) network controller or a building controller. The door controller typically handles two card readers, so it can regulate one or two doors, depending on whether one door is using a card reader for both entrance and exit. It would typically control three devices: a door contact (which tells the system if the door is opened or closed), the door lock and a card reader. Above the door frame would be a powered junction box, which powers each of the devices.

Security systems are now being designed across networks, and are using TCP/IP protocol to communicate to remote devices. Access control is no exception.

In IP-based systems, there is a direct network connection to either the door controller or the card reader, with the network connection providing low-voltage power, typically called Power Over Ethernet (POE). POE powers the door contact, the lock, the card reader and the request to exit (REX) device.

One of the most critical issues in designing access control or any network infrastructure is ensuring the right power source equipment is selected for the job. Many POE network switches do not have full POE capability to every port. When specifying a certain POE switch, make sure it provides the maximum POE wattage of out every port. The current standard is 15.4 watts; however, a new standard of POE plus is being developed, which will provide a maximum wattage of 30 watts.

One excellent example of an IP-based access control system is MAXxess’ netEDGE door controller. The NetEDGE is a high-performance, single-door controller that features a Linux operating system. The Linux OS is embedded in the netEDGE and greatly enhances the reliability and capability of the security management system. In addition, it provides several features to improve performance in any size application.

Because the netEDGE utilizes POE, separate power supplies and multi-door controllers are no longer needed. When utilizing POE for the controllers, readers, lock and REX power, a reduction in installation costs of at least 25% can be realized.
For more information on MAXxess’ netEDGE products, go to http://www.maxxess-systems.com/ or email me at ddamron@sagetechs.com.