When you plan your video surveillance system, there is a maximum amount of distance you can run your power cable to the security cameras. In this blog, we will elaborate more about the difference between using 24vac power supply for camera vs 12 VDC.
The majority of analog security cameras (TVI,CVI,AHD,CVBS) require 12vdc power. The analog security cameras use siamese coaxial cable a pair of wires consisting of coaxial cable 75OHMs and 2/18 gauge power wire. However, there is analog security that takes dual voltage 24VAC and 12VDC.
For commercial security camera installs it is recommended to use dual voltage analog security cameras. Installers will not have to face any issues of voltage drop that happen from using 12VDC. Using a 24VAC power supply and 18/2 gauge the power can run up to 750 feet without any current drop. However, using 12v dc power supply the cable can run up to 250 feet at max, third of the distance that can be run by using 24VAC.
AC vs. DC Power Supply
Regular security camera draws between 0.5 to 1.5 amperes. Pan tilt Zoom cameras require more ampere to run the PTZ motor, ranging from 2-5 amperes.
Installers can use a voltmeter at the end of the wire run to determine how much ampere has been lost. For example, if the power supply puts out 12v dc power, 2 amps at the source, and you read using a voltmeter 1 amp, that implies you lost 1 ampere in the wire. If the security camera only needs 0.5 ampere that implies even with ampere drop the camera will still operate.
Thicker Power Cable
Eighteen gauge wire is the most popular power cable for security cameras. Thicker power wire can be utilized to run further distances. The price of thicker wire might not be as feasible as buying a security camera that takes dual voltage and using a 24VAC instead.
Higher AMP power supply
Another alternative that can be considered is upping your 12v dc power supply. For the further runs buy 3 or 5 amp 12 volt dc power supply so that if power drops you will still have sufficient power at the end of the wire.
The first thing to do is to determine how far the farthest camera from the power source is. If the cable run is less than 250 feet than you can use 12v dc power supply. IF you are running longer runs you might need to consider buying dual voltage cameras, buying thicker wires or higher ampere power supply.
Read More: 12 Volt DC Voltage & Ampere Drop Chart