1. PoE power supply: three standards—don’t buy the wrong one
| Standard | Name | Power per switch port | Actual camera power | Suitable for |
|---|---|---|---|---|
| 802.3af | PoE | 15.4W | Approx. 12.95W | Standard fixed cameras |
| 802.3at | PoE+ | 30W | Approx. 25.5W | PTZ cameras, heaters, fill lights |
| 802.3bt Type 3 | PoE++ | 60W | Approx. 51W | Multi-lens all-in-one cameras, high-power PTZ cameras |
| 802.3bt Type 4 | PoE++ | 90W | Approx. 71W | Professional-grade, outdoor temperature-controlled models |
Key concept:The rating on a switch indicates the “total power budget,” not that every port can deliver its maximum power.An 8-port switch rated at 120W will be fully utilized if all 8 ports are connected to 15W cameras, for a total of 120W. However, if you connect two 30W PTZ cameras, only 60W remains available for the other ports.
2. How to calculate the power budget
| Step | Method | Example |
|---|---|---|
| 1. Check the power consumption of each camera | The “Power” or “PoE” field on the product specifications page | Fixed camera 6–10W |
| 2. Multiply by the number of cameras | Power consumption × number of cameras | 8 cameras × 8W ＝ 64W |
| 3. Add 30% headroom | Reserve for startup peaks and future additions | 64W × 1.3 ≈ 83W |
| 4. Compare the switch budget | The total switch budget must be greater than the amount in Step 3 | Choose a 120W switch |
III. NVR with Built-in PoE vs. Standalone PoE Switch
| Option | Advantages | Disadvantages | Suitable for |
|---|---|---|---|
| NVR with Built-in PoE Ports | One cable does it all, the simplest setup, no additional equipment required | If the NVR fails, everything stops; fixed power budget; number of ports = number of NVR channels | 4–8 cameras, single location |
| Standalone PoE Switch ＋ NVR | Power supply and recording are separate, offering greater expansion flexibility | One additional device and one additional point of failure | More than 8 cameras, multiple floors |
| PoE Injector (Single Port) | Most affordable, suitable for 1–2 cameras | No centralized management; power must be plugged in separately | Small installations with 1–2 cameras |
Practical recommendation:For up to 8 cameras, an NVR with built-in PoE is the easiest option; for more than 8 cameras or installations spread across multiple floors, use a standalone switch.If your NVR only has 8 ports but you want to install 12 cameras, you must add a switch—it is not enough to simply buy an expansion card.
IV. PoE Switches Currently Available
| Model | Price | Description |
|---|---|---|
| Reolink RLA-PS1E PoE Switch [Hong Kong Official Product] | HK$399 | Entry-level PoE switch |
| Reolink POE SWITCH 120W PoE Switch [Hong Kong Official Product] | HK$599 | 120W total power budget, sufficient for 8 fixed cameras |
V. How to Choose an NVR: Five Specifications
| Specification | What to Look For | Why It Matters |
|---|---|---|
| Channels（Channel） | 4／8／16／36 channels | Determines how many cameras you can connect; this is often the biggest limitation when adding devices later |
| Decoding Capability | Not all channel counts support simultaneous 4K decoding | A model labeled 「8 channels」 may support 4K playback on only 4 channels |
| Hard Drive Bays（Bay） | 1 or 2 | 2 bays allow RAID or expansion |
| Built-in PoE | Yes／No, total wattage | If available, it saves you one network switch |
| HDMI output | Resolution | If you plan to connect it to a TV or monitor to view the live feed, pay attention to this |
Decoding capability is one of the most easily overlooked factors
An “8-channel NVR” usually means it can connect to 8 camerasRecording, butsimultaneous displaythe number of channels may be only 4 or fewer, and the footage may be displayed at a lower resolution. If you want to view 8 screens simultaneously on a monitor, be sure to check the “decoding capability” before buying, rather than just the “number of channels.”
6. NVRs Currently Available (Sorted by Price)
| Model | Price |
|---|---|
| EZVIZ R5C NAS Smart Surveillance Host (CS-R5C-V100-8F) [Hong Kong Official Stock] | HK$430 |
| EZVIZ X5S-R100-8W NVR Smart Surveillance Host (CS-X5S-R100-8W) [Hong Kong Official Stock] | HK$499 |
| Reolink NVS4-4-Channel PoE NVR HD PoE Network Video Recorder [Hong Kong Official Stock] | HK$830 |
| Reolink NVS4E-NHD PoE Network Video Recorder [Hong Kong Official Stock] | HK$1,099 |
| Reolink NVS8-NHD 8-Channel PoE Network Video Recorder [Hong Kong Official Stock] | HK$1,178 |
| Reolink NVS16-NHD PoE Network Video Recorder [Hong Kong Official Stock] | HK$1,899 |
| Reolink NVS36 /RLN36 PoE Network Video Recorder [Hong Kong Official Stock] | HK$1,899 |
| Reolink RP-PN16 PoE Network Video Recorder [Hong Kong Official Stock] | HK$2,599 |
| Reolink NVS12W WIFI, 2TBHDD NVR [Hong Kong Official Stock] | HK$2,599 |
| Reolink NVS8-NHD 8-Channel PoE Network Video Recorder (Built-in 2TB Hard Drive) [Hong Kong Official Stock] | HK$2,599 |
| Reolink NVS16 4TBHDD NVR [Hong Kong Official Stock] | HK$3,599 |
| Reolink NVS8-5MB4 2TBHDD NVR KIT [Hong Kong Official Stock] | HK$3,899 |
| Reolink NVS8-5MD4 2TBHDD NVR KIT [Hong Kong Official Stock] | HK$3,899 |
| Reolink NVS8-8MB4 2TBHDD NVR KIT [Hong Kong Official Stock] | HK$4,599 |
| Reolink NVS8-8MD4 2TBHDD NVR KIT [Hong Kong Official Stock] | HK$4,599 |
7. Bandwidth: Why Does the Footage Lag?
| Resolution | Typical Bitrate | Daily Usage per Camera | Daily Usage for 8 Cameras |
|---|---|---|---|
| 2MP / 1080p | 2 Mbps | Approx. 21.6 GB | Approx. 173 GB |
| 4MP / 2K | 4 Mbps | Approx. 43.2 GB | Approx. 346 GB |
| 8MP / 4K | 8 Mbps | Approx. 86.4 GB | Approx. 691 GB |
Calculation method:Bitrate (Mbps) ÷ 8 × 86400 = GB per day. H.265 encoding saves approximately 40–50% more storage than H.264, so models marked H.265 will have significantly lower actual storage usage.
8. How to Calculate Hard Drive Capacity
| To retain recordings from | 4 4K cameras | 8 4K cameras |
|---|---|---|
| 7 days | Approx. 2.4 TB | Approx. 4.8 TB |
| 14 days | Approx. 4.8 TB | Approx. 9.7 TB |
| 30 days | Approx. 10.4 TB | Approx. 20.7 TB |
Formula:GB per camera per day × number of cameras × number of days ÷ 1000 = TB. The table above is estimated at 8Mbps / 4K. Actual usage will vary depending on scene activity, encoding, and frame rate. It is recommended to allow an additional 20% of capacity.
Some of our NVRs come with built-in 2TB or 4TB hard drives (as indicated in the model details); the rest are bare units and require you to provide your own hard drive. We recommend usingsurveillance-grade hard drives(such as WD Purple and Seagate SkyHawk). Do not use standard desktop hard drives—surveillance hard drives are designed for continuous 24/7 writing, and their service lives differ significantly.
9. Cabling and Networking: Five Practical Tips
- Maximum length of a single network cable: 100 meters—Add a switch as a repeater beyond this distance, or switch to fiber optic cable
- It is recommended that the NVR and cameras use a separate network segment—This avoids consuming office bandwidth and is also more secure
- Do not use indoor network cables outdoors—Ultraviolet rays and rain will make the outer jacket brittle; use outdoor-rated cables or conduit
- Waterproof the connectors—Outdoor connectors should be fitted with waterproof boxes or self-fusing tape; this is the most common point of failure
- Add a UPS—The NVR and switch must both remain powered during a power outage; otherwise, recording will be interrupted
10. Frequently Asked Questions
Can PoE switches mix and match cameras from different brands?
Yes. PoE power delivery is standardized (802.3af/at), so it works across brands. Whether recording works is an ONVIF issue and is unrelated to power delivery.
Does an NVR have to be connected to a monitor?
No. Most NVRs can be managed through an App or web interface, but HDMI output makes it convenient to view footage in real time.
Can I use only a switch without an NVR?
Yes, if the cameras support microSD or FTP uploads. However, centralized playback and management will be much more troublesome.
How many days of recording can 2TB store?
Approximately 5–6 days for 4 4K cameras, and 11–12 days for 4 1080p cameras. The actual duration depends on the bitrate.
If the NVR fails, can the footage on the hard drive be retrieved?
Most NVRs use proprietary formats, so the footage must be read by the same model or a compatible device. We recommend regularly backing up important footage.
Do I need to buy PoE++?
Only high-power devices, such as large PTZ cameras and cameras with heaters, require it. Standard fixed cameras are adequately powered by 802.3af.
11. Further Information and Related Topics
- WiFi Cam or PoE Cam— Four Power Supply Methods and Brand Selection
- Complete PoE Wired CCTV Solutions— Budget Packages and Practical Cabling
- How Much Does Shop Security Cost?
- Comparison of 27 EZVIZ Models