CCTV power cord wiring skills

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vedard
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Joined: Wed Dec 05, 2018 12:27 am

CCTV power cord wiring skills

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The power cord is generally arranged separately and a master switch is placed in the monitoring room to directly control the entire monitoring system. Under normal circumstances, the power supply line is wired as AC 220V, and then converted to DC 12V by the adapter at the camera end. The advantage of this is that bus-type wiring can be used and not require bold wires.Of course, it must meet the specifications in terms of fire safety. (Wear steel pipe or flame-retardant PVC pipe), and leave a certain distance from the signal line.
Some small systems can also use 12V direct power supply, that is, use a high-power DC regulated power supply to power the entire system in the monitoring room. In this case, the power cord needs to use a wire with a thicker diameter and the distance should not be too long, otherwise the system will not work properly. This is because when the power supply is constant, the lower the voltage, the larger the current, and the large power supply can also produce a larger voltage drop on a smaller line resistance, making the camera's power cannot reach the required value. In this case, the image of the camera is either jittery, achromatic, or no image at all. At this time, under the premise of loading(that is, without disconnecting the camera power), measure the voltage value at its power port of the camera. You will find the problem ( The voltage value at this time may be only about 10V). 
Many engineering companies have encountered similar problems during the first commissioning of TV monitoring systems powered by DC 12V power supplies. In this case, if it is not convenient to change to AC 220V power supply, and it is inconvenient to replace to the thicker wire, you need to use an adjustable DC power supply to increase the power supply voltage to 13~14V. Ensure that the working voltage at the camera port reaches 12V. But it should be noted that this approach is not a normative approach, but merely a remedy.
In particular, when the distance between the cameras and the central control room is large, it may damage the nearby cameras that have been working normally, because the length of the power cord from the camera to the control room is short (the wire resistance is small). Will produce too much voltage drop, and this kind of practice will make its power port voltage rise to 13~14V. In this case, you can only use multiple power supplies to supply power separately, that is, the standard voltage is used for short-distance power supply, and the longer-distance uses a slightly higher voltage.
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