PoE vs SMPS for CCTV Cameras: Which Power Solution Do You Really Need?

Each CCTV camera needs its own power source, and depending on whether you will decide to go for the ShieldPlus POE Switches, SMPS & Adapters, you will find that this choice will influence your cable installation, the expenses, and the scalability of your security camera system. Both solutions offer similar services although this is done in different ways.

In regards to the PoE versus SMPS for CCTV cameras issue, we can make a brief conclusion like this: POE supplies power and data simultaneously via one network cable, therefore, it is applied to IP CCTV camera systems only. SMPS offers the DC power voltage to the camera via dedicated power cables from one central power supply unit. There is no universal solution in this case your choice should be made considering the type of your CCTV cameras, the cable length and your system wiring.

This guide explains the whole process in detail.

PoE vs SMPS for CCTV Cameras: What's the Difference?

The core difference in any PoE vs SMPS CCTV comparison comes down to how power reaches the camera.

PoE (Power over Ethernet) Delivers power supply as well as network signals through one Ethernet cable, utilizing either a PoE switch or a PoE injector for powering purposes. This can be done for IP cameras which support POE technology and connect to an NVR network-wise.

SMPS (Switched-Mode Power Supply) delivers DC power via a separate power line from the video/data cable. This is the usual power provision for HD analog (AHD/CVI/TVI) cameras when used with a DVR, and this is also how non-PoE IP cameras will be powered when used with a separate data cable.

Briefly: PoE provides power and data in one cable and one device. In the case of SMPS, these two operations are done separately. This is the single factor that influences most other differences between PoE and SMPS.

What Is PoE in CCTV?

PoE refers to a method of transmitting electrical power through an Ethernet cable alongside the data being sent via the same. This feature allows for the IP camera to obtain its power source and networking connection using only one Cat5e or Cat6 cable, without requiring another for power supply.

PoE is supplied by one of two devices:

• PoE switch it is a network switch having power sourcing capability on some or all of its ports, thus connecting several cameras to the network and simultaneously supplying power to them.
• PoE injector it is a one-port unit which supplies power to an already existing Ethernet connection; comes in handy when powering just one camera is needed or when PoE is not supported by the network switch.

PoE delivery follows IEEE standards that define how much power a port can safely supply:

• IEEE 802.3af (PoE): power output is 15.4W and reaches 12.95W to the camera taking into account cable losses.
• IEEE 802.3at (PoE+): power output is 30W and reaches 25.5W to the camera.
• IEEE 802.3bt (PoE++): power output is between 60–90W depending on type and is used for high-power

However, most stationary IP cameras for CCTV systems will only require power of 802.3af level. For PTZ cameras, heated cameras, and cameras with integrated infrared illuminators for long-distance night vision, higher power of 802.3at or greater is needed.

A basic PoE-based CCTV setup looks like this:

Camera → Ethernet cable (Cat5e/Cat6) → PoE switch → NVR/network

What Is SMPS in CCTV?

The Switched-Mode Power Supply is a device that transforms AC mains power into DC output power, which is further transmitted to one or several CCTV cameras via independent power wires. It is a power delivery technique that has been used in analog and HD-analog CCTV cameras for many years, even now being frequently employed in hybrid and budget-conscious systems.

In general, an SMPS can provide power output channels ranging from 4, 8, and 16 and more, each supplying one camera independently. Therefore, this technology is actually a type of centralized power delivery technique: instead of having separate adapters for every camera, all power output for all the cameras in the system comes from one unit at a central location.

SMPS units are available in two common configurations:

• Output channels for individual cameras Each camera gets its separate output port, which ensures that a problem with one of the output channels will not affect other channels.
• One output port all cameras are connected to the same output port.

A basic SMPS-based CCTV setup looks like this:

Camera → DC power cable → SMPS unit → AC mains input

The video and data are transferred separately; the former through coaxial cable (analog and HD analog cameras) and Ethernet cable (IP cameras) that is not PoE-powered.

PoE Switch vsSMPS: Comparison Table

PoE vs SMPS CCTV: Which One Is Better?

There's no universal winner here. The right power solution depends on several factors specific to your installation:

• Camera type Is it a PoE camera or an analog/HD analog camera that uses DC power source?
• Number of cameras For bigger systems, centralization of power is preferred as it is provided by both PoE switches and SMPS with multiple channels.
• Current setup PoE is preferred where there is current Ethernet structured wiring. On the other hand, if you have current coaxial wiring, then SMPS will preserve your infrastructure.
• Cable layout and distances This factor varies for each system in terms of its influence on both options (explained below).
• Power needs if your system uses PTZ cameras or cameras with a heater, then you require PoE+ or PoE++ or a higher capacity SMPS channel.
• Budget Consider the whole installation cost instead of only the unit cost.
• Expansion plans A PoE switch with extra ports or SMPS with extra channels helps in future addition of cameras.

PoE vs SMPS CCTV Power Supply Comparison by System Type

CCTV setup having 1-4 cameras: Single PoE injector or small PoE switch will be an ideal choice for IP cameras. A small 4 channel SMPS will serve the purpose well when it comes to analog cameras.

CCTV setup having 8-16 cameras: Either a single 8 port PoE switch or 16 port PoE switch will do well because it will help you manage all power supply and networking through one device. In case of HD analog system, a multi-channel SMPS with separate output ports is an ideal choice.

CCTV setup having more than 16 cameras: Managed PoE switches having predefined power budgets will help you monitor and debug a larger number of IP camera installations easily. Larger analog installations will use more powerful SMPS units and sometimes more than one SMPS unit scattered at the site location to reduce cable length.

IP camera system: Use of PoE will be more effective, as no additional power cables will be required. IP cameras which don’t support PoE can run on SMPS if there is a separate Ethernet cable for them to communicate.

Wired analog/HD-analog CCTV systems: The standard for powering such cameras would be SMPS, as they do not support PoE and use coaxial cables to transmit video.

New installation: In case you are starting a new installation using IP cameras, PoE can simplify your installation process significantly.

Existing installation: In case you have existing coaxial cables and/or a system powered by SMPS, it would require cabling work for PoE.

Advantages of PoE for CCTV Cameras

• Installation of a single cable both power and data go via an Ethernet cable, minimizing the number of cable drops for each camera.
• Simpler cabling process no need for a separate DC cable or adapter at each location of the camera.
• Network management PoE switches allow you to control your camera's connection as well as its power supply in managed PoE switches.
• Camera expansion installing a new camera usually involves connecting one cable to an unused port on the switch.
• Compatibility with modern IP camera systems PoE power supply system is a standard power solution for most IP cameras today.

Advantages of SMPS for CCTV Cameras

• DC power distribution centralized – One single unit powers several cameras through centralized distribution without using PoE-enabled cameras or switches.
• Compatible with analog and HD-analog cameras – SMPS is the conventional power solution used in cameras that do not support PoE at all.
• Familiar installation procedure – Installers who have worked with SMPS based solutions are familiar with how to install this kind of system.
• Flexible for hybrid systems – The SMPS can also be used to power IP cameras that do not support PoE at all.

PoE vs SMPS: Installation Differences

The difference between PoE and SMPS installation lies in the number of cables used per camera and the location of the power source.

PoE installation path: Camera -> Ethernet cable (Cat5e/Cat6) -> PoE switch -> Network switch/NVR

A single cable is used per camera. PoE switch is placed close to the NVR and all the cameras have connections to their ports over a certain cable distance.

SMPS installation path: Camera -> DC power cable -> SMPS unit -> Mains power input (Video/Data cable run separately Coaxial for analog/HD-analog, or just standard Ethernet for non-PoE IP cameras).

Two cables are used per camera: one for power and another for video/data. SMPS unit is installed close to the DVR/NVR, just like PoE switch.

All the specific details about the exact cable path can vary depending on your cameras, cables distances, positions of your DVR/NVR and power supplies. Site survey will give you the best information about the cable path.

PoE vs SMPS for Long-Distance CCTV Cameras

Distance via cable is a real restriction for either option, and it’s a good idea to understand it before moving forward with design work.

PoE/Ethernet limitations: Standard Ethernet cables (and PoE with it) have a maximum distance of 100 meters (328 feet) from the switch to the camera. This distance restriction applies due to the nature of the Ethernet signal, not due to PoE restrictions specifically. The farther the distance goes beyond 100 meters, the worse will be signal integrity, regardless of the amount of electricity available. PoE extenders will allow extending the effective distance, but they will slow down the networking speeds and add an additional device to the chain which has its own power requirements.

Voltage drop and SMPS: The DC electricity transmitted over long distances by long cable loses voltage because of the resistance — the longer the cable run, the more the voltage gets lost during transmission. Such a low voltage can lead to erratic behavior, rebooting or even failure to start the cameras, if the voltage level becomes less than minimum required by the camera.

This is true for both systems and neither can be taken for granted as working without fail over an “unlimited” distance. For both PoE and SMPS, there are aspects that include the cable itself as well as its length and thickness.

PoE vs SMPS Cost Considerations

Comparing cost fairly means looking at the full installation, not just the price of the power unit itself.

PoE cost factors:

• Cost of the PoE switch/injector (usually more expensive than a standard SMPS with the same channel count)
• Network cabling (Cat5e/Cat6) - usually just one run per camera
• Reduced need for installation due to just one cable run per camera
• Maintenance will be performed in one place (the switch) in the long run

SMPS cost factors:

• Unit cost of SMPS (usually cheaper per channel than equivalent PoE switch)
• Power cable in addition to video & data cables
• Extra connectors (for DC, video, data)
• Labor to install and terminate both types of cables per camera site

In the case of a new installation of IP cameras, the use of PoE could be more cost-effective compared to SMPS even if the price of the switch used for the PoE is relatively higher. In the case of an existing analog system, the SMPS will be a more cost-effective solution compared to PoE because it does not require cabling of the whole area using Ethernet cables.

How to Choose Between PoE and SMPS for CCTV Cameras

Choose PoE when:

• You will be using IP cameras that use PoE technology
• You are going to establish a completely new cabling system and reduce the length of cables
• You will be using a single switch to control both power and data
• You have enough cameras and sufficient power for the PoE switch

Consider SMPS when:

• The cameras used are analog or HD analog that does not support PoE
• The installation currently has coaxial or power cables installed
• The CCTV system relies on DC power distribution system in a centralized manner
• Powering of IP cameras that do not support PoE along with a data cable

These are just some general guidelines and not hard and fast rules, as the real answer can only be found through an appropriate site survey, taking into consideration camera specifications, cable placement, and possible future extensions.

Common CCTV Power Supply Problems

Camera keeps restarting: Generally due to insufficient power supply to the camera, where the power budget of the PoE switch is stretched beyond capacity over multiple ports, or where voltage drop occurs on the SMPS cable due to its length.

Camera has intermittent power supply: Investigate whether the DC connector is loose for cameras that use an SMPS or whether the particular PoE switch port is failing. Inadequate cable or connection quality is usually the reason for both systems.

Voltage drops on cable run: This is the traditional SMPS problem for cameras located far away from the power supply unit. To avoid voltage drop, you can increase cable size on long runs or relocate the SMPS closer to the cameras.

Overloading of the PoE switch: If the number of cameras added exceeds the total power budget available at the switch, there will be some ports dropping off their connected devices. Ensure that your switch has sufficient power budget for the total number of cameras to be added.

Insufficient output of SMPS: When the number of cameras connected to the single-output SMPS is greater than the rated one, instability will occur in all the cameras. It is better to use multi-channel SMPS with separate outputs to isolate this problem in one camera instead of the entire set.

The quality of the cable: Poor quality or poor-sized cables increase the resistance, which further increases the voltage drop in SMPS systems and the PoE power supply over the distance. The quality of the cable becomes even more important as the cable length becomes longer.

Unawareness about the camera power needs: Not all cameras require the same amount of power to function. The power consumption of PTZ cameras, cameras with internal heaters, or cameras with effective IR illuminators is usually higher compared to a common fixed camera.

How ShieldPlus Can Help With Your CCTV Power Setup

Selection of PoE or SMPS will not only depend on the products but will also be determined by your camera type, current cabling system, site layout, and space available for further development.

In ShieldPlus, you can find the PoE switches as well as SMPS, and the additional equipment necessary for their use, such as Cat6 networking cables, connectors, as well as waterproof PVC junction boxes.

For the IP cameras, network infrastructure, and PoE systems, there is a category POE Switches, SMPS & Adapters with several types of PoE switches, varying in number of ports and power consumption, ranging from mini 4+2 to more advanced 16 port giga ones, as well as waterproof PoE extenders for outdoor cameras located far from the main PoE switch.

Whereas your CCTV system uses either analog or HD analog cameras or even a combination of both this collection features multi-channel SMPS devices with both plastic and metal bodies and also single-output ports based on the extent of fault isolation that your system requires.

For bulk installers and dealers who will require larger installations of ShieldPlus products, there are wholesale prices for PoE switches, SMPS units, as well as network cables and accessories that will be used in connecting the system. In case you have any doubts about which power solution is most appropriate for your cameras and cabling setup, you may contact the support team first.

No matter which way you go with this, using the right power solutions together with your cameras and cabling solution is what makes your CCTV system stable and easily manageable.

Frequently Asked Questions

Is PoE better than SMPS for CCTV?

None of these two can be said to be superior to another. PoE tends to be easier for PoE-ready IP cameras. This is due to the nature of PoE where both the power supply and the data transmission happen using one cable. SMPS tends to work best for analogue/HD-analogue cameras.

Can PoE replace SMPS in CCTV?

Only if your cameras have PoE functionality. Analog and HD analog cameras do not have PoE functionality, so they need SMPS or other DC source of power irrespective of your network infrastructure.

What is the difference between PoE and SMPS?

PoE provides both power and data through a single Ethernet cable through the use of a PoE switch or an injector. On the other hand, SMPS provides DC power via a separate power cable, and video/data through another cable.

Is PoE cheaper than SMPS?

This is based on the particular setup. The PoE switch can be more expensive to start off with compared to a SMPS switch; however, PoE tends to be cheaper on new installations because only one cable is used per camera. In the case of existing systems with analog cameras, SMPS is the cheaper option.

Which is better for IP cameras?

The PoE solution would be relatively efficient to use in case of PoE-compatible IP cameras because it would get rid of the necessity of using an extra power cable. At the same time, SMPS would allow powering IP cameras that do not support PoE.

Which is better for traditional CCTV cameras?

The power system employed by the analog as well as HD analog cameras is the SMPS because the former are not PoE compatible.

How far can PoE power a CCTV camera?

Standard Ethernet cable is capable of handling PoE up to 100 meters (328 feet) between the switch and the camera. This range is defined by the Ethernet cable standards and not the PoE standards. PoE extenders can increase range but will lower the network speed.

Does every IP camera support PoE?

No, there are IP cameras that have POE and there are some that don't. However, non-POE IP cameras can also use SMPS for power and will use a different Ethernet cable for the data.

Can an SMPS power IP cameras?

Yes, provided the IP camera supports standard DC supply and there is an independent cable for the network connection. SMPS does not supply network data; it only supplies power.

How do I choose the right CCTV power supply?

First off, consider the camera model you have: for a PoE-compatible IP camera, a PoE switch or injector should work, whereas analog, HD-analog, or non-PoE IP cameras would require an SMPS. After that, take into account the amount of cameras, distance between them, and your budget for cable and equipment.