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PoE distance and budget calculator

Check switch budget, per-port class limits, runs past 100 m, and voltage drop. Voltage at the device solves P = V·I − I²R.

Plan

15.4 W allocated of 370 W (4.2%). 354.6 W left. PD draw 12.9 W.

DeviceStandardPD max WAlloc WRun
This run × 1 802.3af Type 1 12.95 15.4 90 m OK

This run

802.3af Type 1

PSE power 15.4 W.

Cable loss 0.7 W on 90 m of 23 AWG.

Power available at the PD 14.7 W.

Voltage at the device 41.9 V.

IEEE 802.3 PoE reference

StandardTypePSE outPD maxMin VMax loop ΩPairs
802.3af115.4 W12.95 W44 V20.02
802.3at230.0 W25.5 W50 V12.52
802.3bt360.0 W51.0 W50 V6.254
802.3bt490.0 W71.3 W52 V6.254

100 m channel. Values from IEEE 802.3 tables via the Ethernet Alliance overview. 23 AWG is 0.066 Ω/m and 24 AWG is 0.084 Ω/m. Four-pair 802.3bt uses half the loop resistance.

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Open a camera to see its manufacturer specs and run this tool with them filled in.

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