How much power budget do I need for a PoE switch?
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✓ Best Answer
Calculating PoE budget correctly prevents port shutdowns and ensures reliable operation.
Formula
Budget = Σ(device wattage) × 1.3 (safety factor) + switch electronics
Typical Device Power Consumption
| Device Type | Typical Draw | Standard |
|---|---|---|
| IP Phone | 3-8W | 802.3af |
| WiFi 5 AP | 10-15W | 802.3af/at |
| WiFi 6/6E AP | 15-25W | 802.3at/bt |
| Fixed IP camera | 4-8W | 802.3af |
| PTZ camera | 15-30W | 802.3at |
| PTZ w/ heater | 30-60W | 802.3bt |
Example Calculation
16-port switch powering: 8× IP cameras @ 8W = 64W, 4× WiFi APs @ 20W = 80W, 4× PTZ cameras @ 25W = 100W. Total = 244W × 1.3 = 317W minimum budget needed.
Rules of Thumb
- Never fully load a PoE switch — target 70-80% max
- Account for future expansion (add 25%)
- Verify per-port limits — some switches limit 30W/port even with bigger budget
- Check power supply redundancy for critical deployments
Warning Signs
- Ports randomly shutting down under load
- Devices rebooting during high traffic
- Switch reporting "power denied" for new PDs
2 Other Answers
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