Does the PSE Type cover the PD Class?
Compare Classes 1–8, power allocated at the source, PD-available power, and the declared per-port ceiling.
Open Class Compatibility Checker →Power over Ethernet workbench
Separate the port, budget, topology, and power mode.
A 90 W switch label does not answer whether one port covers the PD, every device fits together, a downstream switch can pass power, or a passive source is safe.
Switch, injector, splitter, or extender?
Map source, endpoint input, destination count, data need, and distance to an equipment class.
Open Equipment Selector →Will every device fit the switch budget?
Add device groups using one planning convention and reserve explicit headroom.
Open Power Budget Planner →How much reaches downstream PoE ports?
Subtract a powered switch’s self-use and reserve, then apply its declared output limit.
Open Passthrough Planner →Is this passive PoE pair safe to consider?
Keep IEEE detection separate from always-on proprietary voltage, pairset, and polarity.
Open Passive PoE Preflight →Which layer explains the PoE failure?
Use detection, data link, scope, cable, port, load, and injector controls.
Open Failure Isolator →Build and test a PoE path in order
Choose standards and topology, verify per-port and total power, then isolate failures one variable at a time.
Read the PoE planning guide →Types, classes, and evidence boundaries
Use public IEEE and Ethernet Alliance sources without treating a browser estimate as a live measurement.
Open PoE reference →Order: identify IEEE versus passive power → choose the equipment class → check each port → check the whole switch → subtract powered-intermediate consumption → run controlled A/B tests.