PoE Budget and Run Distance

Power available at PD over Cat5e/6/6A given PoE class and run length.

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Formula and source

I = pse_W / V_source; loop resistance R = R_per_100m × (L / 100m) × (1 + α × (T − 20°C)); P_loss = I² × R; PD power = pse_W − P_loss; flagged against IEEE 802.3 class minimums.

IEEE 802.3bt-2018 by name; manufacturer category cable resistance (Belden / CommScope) attributed in shard.

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