This calculator is used to determine the maximum distance a device can be
powered over a length of cable. When running power over any cable there will be a voltage drop. Many power supplies
are solt with a slightly higher voltage output then specified to compensate for
the voltage drop over a cable length. However when running power over long
distances the power supply will not be able to compensate for such a large voltage drop.

CCTV cameras are recommended to run within 10% of their rated voltage, this
is called the input voltage tolerance. Example, if the camera requires 12volt dc or 12vDC power, your power voltage to the camera should be between 10.8vDC to 13.2vDC. Anything less may cause the camera to not function properly. Anything more can cause permanent damage to the camera that will not be covered under warranty. DO NOT OVER-VOLT ANY EQUIPMENT! Most common results from not having enough power are infrared lighting may appear dim, camera video may appear dark or distorted, horizontal lines on the video, or no picture.

When using this calculator it’s extremely important to take into account the CCTV camera’s current. This is typically measured in mA (milliamps) or Amps and can usually be found on the camera’s specifications. If you are unsure of your camera’s voltage and current specifications contact your CCTV camera distributor. Most camera current specifications are based on its maximum current draw. Example, you have a CCTV camera with a 200′ infrared range, during day time when the infrared LEDs are not on the camera only requires 200mA while at night time when the infrared LEDs turn on that camera will draw 1200mA.

This is very important to take into consideration when using this calculator because this variable in current can cause you to over-volt your camera! Current is a huge factor when calculating voltage loss. A camera with no infrared LEDs (200mA) can be run using CAT5 cable and a 12vDC transformer up to 300′ while an infrared camera (500mA) bearly makes it half that distance.

Our best and simplest solution for running power over long distance is a 24vAC to 12vDC power converter. These devices are great for long distance power, simply run the standard 24vAC power over the cable and convert back to 12vDC at the end of the run. This solves problems with variable voltage on IR and mechanical cameras. The converter will take anywhere from 18vAC – 28vAC this allows for a much larger voltage drop and the ability to maintain your 12vDC power.


Below is a table of common wires and their gauges:

Cable TypeCable Gauge (AWG)Cable TypeCable Gauge (AWG)
CAT5e Cable 24 AWGRG59 + 18/218 AWG
CAT6e Cable 23 AWGAlarm Cable22 – 26 AWG


Calculate your maximum cable distance below:


Power Input Specifications:Calculation Results:Maximum Cable Distance:
Input Voltage:VoltsMax Voltage Drop:Volts


Input Current:AmpsTotal Current Required:Amps
Tolerance:%Effective Gauge:AWG
Cable Pairs:CablesCable Resistance:Ohms
Wire Gauge:AWGPower Dissipation:Watt/Ft