Introduction

The Internet Protocol (IP) camera market size is projected to surpass 39 billion by 2033 with a compound annual growth rate (CAGR) of 11.5% a year, according to Precedence research. Driving this growth is the expansion of cameras being deployed outdoors in homes, commercial and residential buildings and smart city initiatives (Figure 1). IP cameras are quickly replacing traditional closed-circuit television (CCTV) cameras, which commonly use coaxial cables and require a second power cable to the device. When deploying cameras outdoors, routing power to the device is more complex and can become costly.

Figure 1 IP security cameras deployed in smart city applications, one sector that is driving the steady growth of IP cameras.

IP vs CCTV

IP cameras have many benefits over traditional CCTV cameras. First, they are connected to a network via a single Ethernet cable. Second, the Ethernet cable can provide both data and power to the devices through a technology called power over Ethernet (PoE). Since PoE is categorized as Class 2 Power—a safe power with low voltage and current that does not present fire or shock hazard according to the National Electric Code—it does not require a licensed electrician to install, thus saving time and installation costs.

PoE is acknowledged as an energy-efficient technology. PoE selectively activates and supplies power solely when a device requests it, delivering the precise quantity of power required. It automatically shuts off upon fault detection or when the device no longer requires power. PoE midspans, equipped with management capabilities, enable the scheduling of power availability.

The evolution of PoE tech

PoE is an IEEE® standard which can provide up to 90 W of power. It was pioneered by PowerDsine in the late 1990s which has now become Microchip Technology’s PoE business unit. PowerDsine was working with the earliest IP phone manufacturers to deliver voice, data, and power over a single Ethernet cable. In 1998 they introduced the first PoE ICs including the power source equipment (PSE) IC which puts power onto an Ethernet cable as well as the powered device (PD) IC, an IC that takes power off the Ethernet cable for the device. Since there were no Ethernet switches in 1998, PowerDsine introduced the first midspan, also known as an injector the following year. A midspan is a device connected to an Ethernet switch that does not provide power, instead it injects power onto a second Ethernet cable connected to the device.

Many IP camera manufacturers offer PoE midspans as a power option in instances where the network for the camera that will be deployed may not offer PoE power. The midspan is analogous to a laptop’s power supply where IP camera manufacturers offer a PoE midspan as a “power supply”.

Today, PoE midspans are a popular choice despite the option to deploy power via PoE switches. Only 20% of existing networks provide PoE power. For those deploying over existing networks that do not offer power, PoE Midspans are the fastest and most cost-effective way to add power to those networks. And even if the network does contain a PoE Ethernet switch there are limitations. They all have a maximum available power for PoE known as a power budget. This is the amount of power available to be offered over the switch’s multiple ports. Most switch power budgets are not enough to provide full power on all ports. Therefore, to supplement power on ports that cannot offer power, the PoE midspan continues to be an excellent option.

Outdoor IP Camera Power Requirements

The first outdoor IP cameras were simple in design and had minimal power requirements. The four basic types of IP cameras are Dome, Bullet, Turret and Fisheye. These are fixed focal lenses lens mounted onto a ceiling or wall with few functions. These cameras usually require no more than the PoE power supplied by IEEE 802.3af (15.4 W at the source) or IEEE 802.3at (30 W at the source).
Today, there are advanced outdoor IP cameras that require more power. Motors have also been introduced into cameras to enable more features such as variable focal lengths and point, tilt and zoom (PTZ) capabilities (Figure 2). These features are often triggered by motion, light or sound sensors reacting to different events.

Figure 2 An advanced point, tilt and zoom weatherproof IP camera with night vision.

Other PoE cameras offer with special features for operating in adverse weather conditions such as lens defoggers. While some offer LED lighting or infrared night vision to monitor areas of low light, as well as storage on the camera itself in case the network fails or is taken down. An emerging popular feature is two-way audio, so people monitoring not only have the ability to see the video feed but can also listen to audio and communicate via the camera as well.

All these features require more power than 25.5 W of power. As shown in Table 1, the IEEE PoE standards offer eight different classes of power that fall into four “types”, offering up to 90 W at the source.

 Table 1 IEEE® 802.3af/at/bt PoE source and device power standards.

Powering outdoor IP cameras

IP cameras that are mounted on the walls of buildings may be supplied power from an indoor PoE source. For far reaching outdoor applications, a separate power supply for the camera is necessary because of the 100-meter cable reach limitation of Ethernet. In that case, it is important to select the right PoE midspan or switch for the outdoor environment.

Many choose to purchase an indoor, or industrial, PoE midspan or switch, and place it in an outdoor enclosure commonly known as a NEMA box to power their outdoor PoE cameras. The National Electrical Manufacturers Association (NEMA) defines standards for different types of electrical enclosures in various environments. These enclosures are excellent for a range of applications; however, deploying PoE midspans or switches in such enclosures usually results in failure because outdoor enclosures can get twice as hot as the ambient outdoor temperature within the enclosure. Extreme heat affects key components such as capacitors and can directly lead to failure. Installing proper ventilation and fans to cool the units can potentially compromise the weatherproof seals, allowing dust, moisture, and water in the unit, which can also lead to failure. Moreover, there is a good possibility that the midspan and switch will fail when deployed with a NEMA enclosure in these extremely cold environments as they are typically not rated to operate below certain temperatures.

In addition, deploying in a NEMA enclosure also requires proper grounding and surge protection to prevent failure from outdoor events such as lightning strikes (Figure 4). Without proper grounding and surge protection, not only can the midspan fail, but it could also damage the IP camera. To prevent power failures and avoid damaging the cameras, the best solution is to find a PoE midspan or switch that is designed for the outdoor environment.

Figure 4 Surge protection must be designed into the NEMA enclosure to ensure the unit is adequately protected against failures from nearby lightning strikes.

What to look for in an outdoor PoE midspan

A considerable number of PoE midspan manufacturers offer indoor devices while few specialize in the production of outdoor units. Ingress protection (IP) ratings are the industry standard for assessing how dust- and water-proof a component is. The IP ratings involve a two-number system where the first digit signifies the level dust resistance while the second digit represents the water resistance. A rating of IP6x signifies that the device is entirely shielded from dust particles. For water resistance, a rating of IP65 protects from dust and low-pressure water jets, IP66 has resistance from strong water jets, and IP67 allows for immersion up to 1 meter for 30 minutes. Many vendors may offer an IP65 rating for outdoor midspans and switches, however, an IP66 and IP67 is recommended to effectively protect the unit from exposure.

It is also important to choose PoE midspans that have built in surge protection to shield it from transient events such as lightning strikes. IEEE 802.3 standards define protection from such events as power surges or lightning strikes through isolation. The conductors of an Ethernet interface must be isolated through grounding or other circuitry. However, this approach typically only protects up to 2 kV. Look for units that are designed to meet industry-defined outdoor protection standards. There are several standards today such as the GR-1089-Core Issue 6 and the ITU-T K.21 enhanced surge level protection that provides up to 6 kV of protection on both data and AC lines.

What to look for in an outdoor PoE switch

Although outdoor PoE midspans are an excellent solution for outdoor IP cameras, oftentimes an outdoor PoE switch is necessary instead. This may be due to the distance from the base network, or because multiple devices need to be managed. The same base criteria for an outdoor PoE midspan is also necessary for a switch where it is important to:

• Avoid placing an indoor or industrial switch in a NEMA enclosure as they have a high incidence of failure.
• Make certain that the unit has a minimum IP66 rating.
• The unit has built-in surge protection.

On top of these features, there are several other characteristics that are important for outdoor PoE switches. Since it will be deployed outdoors in a public area, always make certain that the switch is fully sealed and tamper-proof (Figure 5). There are outdoor switches that must be opened and configured that become security risks. Sealed units can be remotely managed, whereas those that need to be opened cannot be reconfigured once they are installed.

Figure 5 An outdoor switch that is fully sealed can be remotely managed with security features and two fiber ports.

Since the switch is deployed in public, it is important to have the highest level of hardware and software security to avoid hacking. Such features as user authentication, HTTPS, encryption, certificate management, and distributed denial of service (DDoS) are basic features to ensure that the unit will not be compromised.  

Additionally, it is critical to look for a unit that has at least one fiber optic port. Fiber links can provide data over significantly longer distances than Ethernet, enabling data transmission from several kilometers away. Units that have two fiber ports can receive data from long distances and can also forward data to create a daisy chain, eventually returning to the base switch. If the unit has automatic backup failover, it can continue to function and communicate with the base even if one of the fiber links is broken.

Future requirements for outdoor IP cameras

Most of the advanced features available today in IP outdoor cameras require higher PoE power levels. There are new features being added to outdoor IP cameras that will not only demand more PoE power, but they will also require faster data rates. Most of the PoE midspans and switches today support data rates up to 1 Gbps. As more companies incorporate advanced features such as edge computing with AI such as facial recognition, outdoor PoE midspans and switches will need to support higher data rates such as 10 Gbps. 

Today, a few manufacturers of outdoor PoE midspans have models that can support data rates up to 10 Gbps. As these features get added to improve the functionality of outdoor PoE cameras, expect to see even faster outdoor PoE midspans and switches.

By Alan Jay Zwiren, senior marketing manager of Microchip Technology’s Power over Ethernet business unit

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