_3.gif){kind=icon}
_1_1.gif){kind=icon}
Is my switch enough for my cameras?
Sums the maximum power of all devices, adds a 20% reserve and compares it with the switch PoE budget, port count and standard.
How is it calculated?
The maximum power of each device (with IR, heater or motor running) is multiplied by its count and summed, then the reserve is added. The most powerful device defines the port standard (af/at/bt); the number of devices plus uplink ports defines the port count. Example: 8 × 7 W = 56 W → +20% = 67 W → a switch with at least 75 W budget and 10 ports.
Frequently asked questions
What is PoE?
Power over Ethernet — the device receives both data and power over a single network cable. No separate adapter or power outlet is needed.
Why is a 20% reserve needed?
At night, when IR illuminators, heaters or PTZ motors switch on, devices reach their maximum draw. If the budget has no reserve, cameras reboot or turn off exactly at night.
What is the difference between 802.3af, at and bt?
802.3af (PoE) delivers up to 15.4 W per port, 802.3at (PoE+) 30 W and 802.3bt (PoE++) 60–90 W. Standard IP cameras are fine with af; PTZ and cameras with strong heaters need at or bt.
What if the cable is longer than 100 m?
Ethernet is limited to 100 m. For longer runs use a PoE extender, a switch with "Extend" mode (up to 250 m at 10 Mbps) or fibre with media converters.