An apparatus comprises an Ethernet port including high-side transformers and low-side transformers. High-side current paths supply high-side currents form a high voltage rail to high-side center taps of the high-side transformers. Low-side current paths supply or do not supply low-side currents from a low voltage rail to low-side center taps of the low-side transformers, and convert the low-side currents to sense voltages. A controller configures the low-side current paths to either supply or not supply the low-side currents to the low-side center taps when none of the sense voltages exceed a voltage threshold representative of an overcurrent threshold or when at least one of the sense voltages exceeds the voltage threshold, respectively. A current monitor injects additional current into the low-side current paths only when at least one of the high-side currents exceeds the overcurrent threshold.