Powering Access Control

Powering Access Control

New standard allows manufacturers to design products with bigger features

The new IEEE802.3bt PoE standard, also often referred to as PPoE or 4-Pair PoE, is a game-changing solution for powering 12VDC and 24VDC access control and related devices. IEEE802.3bt introduces two new types of PoE; one providing up to 55W and the other up to 75W. Unlike Hi-PoE (60W), IEEE802.3bt uses all four pairs of wire in a structured cable to evenly distribute power. This new standard allows manufacturers of powered devices to design new products with bigger features, faster motors and more capabilities.

To date, there are few products on the market that have already adopted the 802.3bt standard. Aside from PoE lighting, there are some infrared illuminators that adhere to 4PPoE, but now that this standard has been ratified, manufacturers are looking to take advantage of this standard for new products.

There are several sources for PoE injectors that supply 802.3bt up to Type 4. For example, Altronix NetWay Midspans are available in single or multi-port options with larger wattage power supplies to cut down on the number of injectors for larger projects. And just recently, Altronix introduced switches offering 4PPoE outputs. This is a good indicator that we will see a lot more devices demanding more power.

When we think of power supplies, they normally have a high voltage input such as 115VAC that is converted into 24VAC or 12/24VDC. There are other power supplies that accept a 24VAC input and convert to 12VDC or lower. For example, when a simple burglar alarm panel requires 16.5VAC input, the panel converts this to 12VDC. This 12VDC will also power the keypad and charge a battery for backup. Though the video surveillance world is going mostly IP and using PoE for power, HD analog cameras for the most part still require 12VDC.

A big application using power supplies hardwired with high voltage is for the deployment of electrified locks. These power supplies generally take 115VAC power input and reduce this to a 12VDC or 24VDC output. That single output is then connected to a distribution board where the electrified magnetic locks or strikes are connected. Most jurisdictions require that this power input be hardwired with a dedicated circuit. Due to the high voltage, a certified electrician must wire this type of installation.

While some security integrators do have certified electricians on staff, the use of high voltage still adds to the cost of any installation. In large cities like Chicago, Boston, or New York, electricians have offices in the same building as the access control system. This limits contracting your own electrician to do the work. The installation also requires dedicated conduit runs as well as expensive large gauge copper and a dedicated circuit breaker. The new 802.3bt 4PPoE standard helps curtail this costly practice.

4PPoE delivers up to 75W of total power. Using new solutions like Tango PoE driven power supplies from Altronix, we can harness the IEEE 802.3bt standard. Tango solutions allows for a PoE input of 15.4W, 30W, or the new 4PPoE 100W and converts it to a useable 75W of available power. With 75W available, the flexibility to power an entire access control system is a reality.

Here is the breakdown using Mercury boards, one of the most widely used platforms in access control.

Based on this data, you can see that 75W can potentially power an entire 8 door system. If these levels are too close for comfort, there are ways you can save power: use a midspan injector or PoE switch that has battery backup. This would eliminate the battery backup on the PoE driven power supply and alleviate 10W. You can also limit the PoE driven power supply to 4-6 doors and use 2 power supplies, putting the 12VDC devices on one power supply and the 24VDC devices on the other. The cost for the second power supply will certainly be less than using an electrician.

Additionally, the access control manufacturer you are working with may draw less power on the panels. Keep in mind that this method of powering your access control system will eliminate the need to schedule a certified electrician to wire up the power supply. The category cable used for power can run in the same cable trays and paths as other network cabling.

When servicing the system, unplugging the Ethernet cable from the PoE driven power supply is safe with no voltage present. Once the cable is back in, the handshake is performed with the power source and 802.3bt PoE is sent back to power the system.

IEEE802.3bt 4PPoE has made its way into our world of security and we can take full advantage of its characteristics to save money, labor and make our installations much safer to work with innovative PoE driven power supplies like Tango from Altronix.

Take a look at a recent access control project you installed, and calculate how much you would have saved using 4PPoE and a PoEdriven Power Supply. You may be surprised at the savings.

This article originally appeared in the January / February 2020 issue of Security Today.

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