12V DC / 24V AC Max Cable Distance Voltage Drop Chart

CCTV cameras typically use 12V DC or 24VAC power supplies. Some security cameras are dual voltage which means that they can be powered by either 12V DC or 24V AC. AC and DC low voltage power supplies have limitations as to how far cable can be run before the voltage drops too low for your device to use. The maximum length that cable can be run for low voltage power varies based on these factors.

1. Does your camera require 12 volt DC or 24 volt AC power?
2. How much power does the device require? CCTV cameras usually have a maximum power required that is documented in the camera's specification. This is normally specified in amps / milli-amps (mA). For example: DC 500mA, DC 1A. (1 amp = 1000 mA)
3. What size cable are you using? For example: 18 gauge, 16 gauge, 22 gauge, etc. Note: cable size is specified in AWG which stands for "American Wire Gauge".

Power to 24VAC Cameras Can be Run Further than 12V DC Cameras

If you need to run cable from your power supply to your security camera farther, you should consider using 24VAC, instead of 12V DC. Dual voltage cameras are the solution.

• Analog CCTV 24VAC Dual Voltage Cameras
• AHD (analog high definition) 24VAC Dual Voltage Cameras

Low Voltage Power Drop Charts

Note: for both AC and DC low voltage, generally the maximum acceptable voltage drop is 10%. The below charts assume this.

12V DC Power Drop / Max Cable Distance Chart

The below DC voltage drop cable distance chart works as follows. The left column notes the amount of power that the device you are powering requires (red text). The "mA" after the number stands for milli-amps. For example, say you are using a CCTV camera that requires max 300mA. Using 18 gauge power cable, you can run your cable up to 289 feet.

24V AC Power Drop / Max Cable Distance Chart

The AC voltage drop cable distance chart works the same way as the DC one. However, most 24VAC power supplies are measured in voltage amps ("VA"), or watts. Voltage amps / watts can be converted to milli-amps. You can use this voltage to watts conversion tool if the value you need is not in the below chart. We have provided the conversion for you below the VA value in the column on the left. For example, 10VA is the same as 417mA.

Using the below chart, you can see that if you are using a AC powered or dual voltage security camera that requires up to 417mA of power, you run 18 gauge power cable up to 451 feet.

Installer Tools & Reference Pages

Here are some additional reference pages and online tools that installers find useful

• CAT-5 Wiring Diagram - TIA-568B standard Ethernet and crossover cable wiring diagrams.
• Open Port Checker - this online tools tests port forwarding rules on network routers.
• Voltage Drop Calculator - this voltage drop calculator tool is used by low voltage installers to calculate AC or DC voltage drops in amps over varying cable distances.
• Volts to Watts Converter - this online calculator / conversion tool can convert watts to amps, volts to watts, and volts to amps.

Related Security Camera System Equipment

• Hidden CCTV Cameras
• Dome CCTV Cameras
• IR Security Cameras
• BNC To HDMI Converter
• Turret Security Cameras
• 180 Degree Security Cameras

About

This article was written by Mike Haldas, co-founder and managing partner of CCTV Camera Pros. If you found it useful, please share it. If you have any questions, please contact Mike at mike@cctvcamerapros.net.