For the PoE power supply distance, can PoE power supply exceed 100 meters? This question is indeed affected by many factors. Some friends have no effect on power supply over 100 meters, while some have unstable power supply even at 90 meters. Here we will discuss it together. You must have seen the PoE power supply switch products with 200 meters, 250 meters, and 300 meters in the circle of friends or online publicity. There will be a doubt: Isn't the transmission distance of network cable 100 meters? What kind of cable can reach the publicized distance?
The long-distance transmission of more than 100 meters must be above category 5 and use 8-core network cables. At the same time, the PoE switch is 8-core power supply, and the camera must also be 8-core power receiving. Another key point is that the PoE switch device supports network extension mode. After enabling it, when using category 5 and above network cables, the data transmission and power supply distance of the corresponding port can reach up to 100 meters or more. For ordinary PoE switches, we recommend that it is more appropriate to be within 100 meters.
Why is it recommended to use a distance of less than 100 meters? Let's look at the resistance of various types of network cables. The resistance of various materials of Cat5 twisted-pair network cables for 100 meters is as follows:
Copper-clad steel mesh wire: 75-100Ω
Copper-clad aluminum network cable: 24-28Ω
Copper-clad silver network cable: 15Ω
Copper-clad copper network cable: 42Ω
Oxygen-free copper network cable: 9.5Ω
The shorter the distance, the lower the resistance, and the oxygen-free copper network cable has the lowest resistance, so it is the most stable power supply. The resistance of 100 meters is only 9.5Ω. If it is 50 meters, then its resistance is half of 9.5Ω. The lower the power loss of PoE power supply (power loss formula, Q=I²Rt, power loss is proportional to resistance), the more stable the power supply. Therefore, it is necessary to use good network cables for transmission over a distance of more than 100 meters.
