There is a new power standard in the city, and it has several names. Officially it is 802.3bt, but others call it 4PPoE or 4 pairs of PoE. The Institute of Electrical and Electronic Engineers (IEEE) ratified this new PoE standard in September 2018, and integrators are discovering that this new standard can change the game about how PoE can be used.
As 802.3bt makes its way into our world of security, integrators can take full advantage of its features to save money, labor and make facilities much safer to work. These power supplies and converters powered by PoE, as well as the power supplies for this new standard are available today and can be found on the shelf of some of your local distributors.
PoE before the new standard
In most cases, when using PoE, an integrator only connects a PoE device, such as a camera, an illuminator, an access control panel, an access point, lighting, etc. In some cases, the PoE 802.3af 15.4W Type 1 or PoE + 802.3at 30W Type 2 simply did not provide enough power. In these scenarios, manufacturers had two options for designing products:
- Option 1: Use PoE and a separate low voltage AC or DC power connection, that is, PoE and 24 VAC. This would allow the PoE to power the PTZ camera, while the 24 VAC would power the heater / fan or infrared LEDs.
- Option 2: Use a non-standard PoE called "Hi-PoE" or "PoE ++" that delivered up to 60W of power. Some would think that this is the same as 802.3bt Type 3; However, it is not.
Traditional PoE is delivered in one of two ways. Mode "A", which is normally found on a PoE switch, offers PoE on the same two pairs as data on a category cable. Mode "B", which is found on many PoE injectors, delivers PoE in the spare pairs, leaving the data pairs only for data. Hi-PoE uses Mode "A" and Mode "B" simultaneously, which offers what some specification sheets call Hi-PoE 802.3at (60W) even though it is not really a standard. Using a PTZ camera that works using Hi-PoE as an example, Mode “A” 30W will power the PTZ and the motor, while Mode “B” 30W will power the heater / fan, totaling 60W.
Going beyond Hi-PoE
IEEE802.3bt is a different animal and introduces two new types of PoE. Type 3 is up to 55W and type 4 is up to 90-100W. This means that, instead of dividing the PoE into Mode "A" and Mode "B", as is the case with Hi-PoE (60W), the 802.3bt standard uses all four pairs to distribute power evenly . The amount of power available for Type 3 is 51W and Type 4 allows up to 75W.
As it is relatively new, there are very few products on the market that have already adopted 802.3bt. In addition to PoE lighting, as of today there are some infrared illuminators that adhere to 4PPoE.
This new standard allows manufacturers of powered devices to design new products with larger features, faster engines and more capabilities. With the news that the standard has been ratified, manufacturers will begin to take advantage quickly and new products will soon be available.
Currently, there are several sources of PoE injectors that supply 802.3bt up to Type 4. They come in single or multiple port options with higher power supplies to reduce the number of injectors for larger projects. We will see many more PoE switches that offer 4PPoE outputs in 2020, which is also a good indicator that we will see many more devices that demand more power.
How 802.3bt eliminates high voltage
There are other ways to use PoE that go beyond plugging it directly into a powered device. When we think of power supplies, they usually have a high voltage input, such as 115 VAC that converts to 24 VAC or 12/24 VDC. There are other power supplies that accept a 24 VAC input and convert to 12 VDC or less.
Almost everything we do in the security industry involves voltage conversion. When a simple burglar alarm panel requires a 16.5VAC input, the panel converts this power to 12VDC, which powers the keyboard and charges a battery as a backup.
Although the world of video surveillance is becoming primarily IP and uses PoE for power, analog HD cameras, for the most part, still require 12VDC.
Access control panels vary, but they also accept power inputs of up to 30 VDC and convert it into a lower usable voltage to power devices such as card readers. Also in access control, we are seeing a high demand for wired power supplies with high voltage for electrified locks. These power supplies generally take a 115 VAC power input and reduce it to a 12 V DC or 24 V DC output. That unique outlet is connected to a distribution board, where electrified magnetic locks or strokes are connected.
Most jurisdictions require that this power input be wired to a dedicated circuit, and due to the high voltage, a certified electrician must be used to wire this portion correctly.
While some electrical homes are well versed in safety and some safety integrators have certified electricians on staff, the use of high voltage still increases the cost of any installation. In many large cities like Chicago, Boston, New York, Philadelphia, etc., electricians have offices in the same building where the access control system is being installed. This limits the ability of an integrator to hire their own electrician to do the job. In addition to hiring the electrician, due to the high voltage, the installation now requires dedicated conduits for electricity, as well as the expensive large-gauge copper and a dedicated circuit breaker.
How do we limit this expensive practice? The answer is in the new 802.3bt 4PPoE standard. As indicated above, 4PPoE offers up to 75W of total power. Why do we have to connect this to a camera or illuminator that takes PoE? Instead, integrators can convert this PoE to a lower DC voltage; after all, the nominal voltage of the PoE is 48 V DC.
In the end, integrators can take advantage of the latest IEEE 802.3bt standard when used with a PoE-powered power supply. This type of power supply allows a PoE input of 15.4W, 30W or the new 4PPoE 100W and converts it into an available power of 75W.
Case in point: a typical eight-door access control system
While there are PoE adapters that convert to 12VDC or 24VDC, the available power is limited. With 75 W available, the flexibility to power a complete access control system with 4PPoE is a reality. This includes feeding panels, locks, readers, output requests and charging batteries with a single Category 6 cable (see the table below).
Although it is at the limit, 75W could power a complete eight-door system. If this is too close for comfort, there are ways in which the integrator can save energy: one way is to use a medium-range injector or a PoE switch that has a battery backup, which would eliminate the battery backup in the power supply. Powered by PoE and will relieve 10W. If that is not the route you want to take, limit the power supply powered by PoE to 4-6 doors and use two power supplies: place the 12 V DC devices in a power source and the 24 V DC devices in the other. The cost of adding the second power supply will certainly be much less than the use of an electrician. In addition, the manufacturer of the access control you are working with may consume less power on the panels. These are all things to consider when designing a system.
Keep in mind that this method of powering an access control system will eliminate the need to program a certified electrician to connect the power supply, run a dedicated conduit to the electrical panel. The category cable used for power can work in the same cable trays and routes as other network cables, as well as the access control cable. When servicing the system, there would be no high voltage inside the cabinet and disconnecting the Ethernet cable from the power supply powered by PoE is safe with no voltage present. Once the cable is plugged in again, the link protocol is performed with the power supply and 802.3bt PoE is sent to power the system.
Take a look at a recent access control project that you installed and calculate how much you would have saved using 4PPoE and a PoE powered power supply. I think it will surprise you.
Ronnie Pennington is a national sales engineer at Altronix Corp. Request more information about the company at www.securityinfowatch.com/10212790.