PoE++ Type 4
Power over Ethernet · 10 specs
Direct Answer
Power over Ethernet Plus Plus Type 4 (High-Power PoE++, IEEE 802.3bt Type 4) is the highest standardized PoE tier, delivering up to 90.0 W (and up to 99.9 W maximum) from the PSE to guarantee 71.3 W of DC power across all four pairs to high-draw client hardware.
Source: IEEE 802.3bt-2018 (Clause 145) / TIA TSB-184-A · Last reviewed Aug 28, 2026
Specs
| IEEE Standard | IEEE 802.3bt-2018 |
| PoE Type | Type 4 (High-Power PoE++) |
| PoE Power Classes | Class 7 (75W PSE) and Class 8 (90W PSE) |
| PSE Output Power (Max) | 90.0 W (up to 99.9W) |
| PD Input Power (Guaranteed @ 100m) | 71.3 W |
| PSE Output Voltage Range | 52.0–57.0 V DC |
| PD Input Voltage Range | 41.1–57.0 V DC |
| Max Current | 960 mA per pair set |
| Twisted Pairs Energized | 4 pairs (4PPoE) |
| Recommended Cable Category | Category 6a (23 AWG solid copper) |
Thermal Management and Cable Bundling
Delivering nearly 1 Amp (960 mA) of continuous DC current per pair set generates significant Joule heating inside enclosed conduit and dense cable bundles. Under TIA TSB-184-A guidelines and National Electrical Code (NEC) Section 725, large bundles of Type 4 cables can overheat, increasing signal attenuation and damaging PVC jackets.
For 90W Type 4 installations, Category 6a or Category 7 shielded cables with heavier 23 AWG solid copper conductors and 75°C/90°C temperature-rated jackets are strongly recommended over 24/26 AWG Cat 5e.
Autoclass Feature and Class 8
Type 4 incorporates the 'Autoclass' protocol defined in IEEE 802.3bt Clause 145. During startup, the PD draws its peak operational load, allowing the PSE to measure exact channel resistance and optimize power allocation rather than reserving the full 90W theoretical ceiling.