PoE HAT

Galvanic Isolation:

Power-over-Ethernet specification requires that both power source (switch) and power consumers (device) should provide galvanic isolation to avoid ground loops, a condition where the voltages of the ground planes differ and cause a short circuit.

For applications where the Raspberry Pi is connected to external grounded devices such as HDMI TVs or powered USB hard drives, we recommend the isolated model to protect from ground loops in case the PoE switch does not properly implement isolation. Additionally, large or critical deployments should only use the isolated model to protect from surges and other circuit interference to ensure optimal data performance.