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How many devices can be powered by a PoE switch?

Latest reply: Nov 7, 2019 11:28:39 403 2 3 1

Friends who are new to PoE power supply may not know much about it or know how to choose it. They don't know how many devices a PoE switch can supply.


To see how many cameras a PoE switch can supply at the same time, consider two aspects: the power supply standard of the PoE switch and the total power supply of the PoE switch. The power supply of a PoE switch can be understood as the single-port power supply of a PoE switch. There are two standards for popular PoE switches on the market, IEEE802.3af, and IEEE802.3at.

The IEEE802.3af standard defines a power supply of 15.4W. The IEEE802.3at standard defines a power supply of up to 30W. The power supply of a single port varies depending on the power supply standard. For example, the camera power is 9W, and the af standard PoE switch can be used.

The total power of a PoE switch is a very important indicator, which is directly related to how many cameras can be brought. For a 24-port PoE switch with a power supply of 400W, the total power of the PoE switch after removing the loss is about 370W.

Under the IEEE802.3af standard, it can supply 24 ports (370/15.4=24), which can supply 24 cameras at the same time, that is, full load power.

However, if it is calculated according to the IEEE802.3at standard single-port maximum power supply 30W, at the same time, it can only supply 12 ports (370/30=12).

In addition, when purchasing, it depends on whether the switch supports dynamic power allocation, so that each port only allocates the actual power used, so that the power of the PoE switch can be utilized more efficiently.


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Created Oct 14, 2019 01:52:08 Helpful(0) Helpful(0)

Right and clear.
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Created Nov 7, 2019 11:28:39 Helpful(0) Helpful(0)

In actual deployment, the power loss of cables also needs to be considered.
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