Complete Guide to the CCTV Series: A Decision-Making Path Starting with “How Many Cameras to Install” (All 8 Articles in One Place)

This page is the entry point for the entire CCTV series.Eight articles may seem like a lot, but they all come down to one question:How many cameras do you need to install?Once you answer this question, the links below will take you directly to the one or two articles you need to read—no need to go through everything from start to finish.

The in-store CCTV articles cover power supply, NVRs, switches, storage, brand comparisons, and actual installation. This page reorganizes them in “decision order” and indicates when you need to read each article.

Step 1: Count the cameras

How many cameras do you need to install?	Read this article directly	Then read
1–2 cameras	WiFi Cam or PoE Cam	SD Card vs NVR
3–4 cameras	SD Card vs NVR	How to Choose from 13 NVRs
5–8 cameras	How to Choose from 13 NVRs	Three Formulas
9–16 cameras	How to Choose from 13 NVRs	PoE Switches
17+ cameras	NVS36 36-Channel Real-World Setup	PoE Switches

The core logic of this table:The number of cameras determines whether you need an NVR; once you need an NVR, whether the NVR has PoE ports determines whether you need a switch. Once you understand these two points, you will not buy the wrong equipment.

Step 2: What each of the eight articles covers

Article	What question does it answer?	When should you read it?
WiFi Cam or PoE Cam	How to choose between four power options (battery / WiFi / PoE / DC), and the differences between Reolink and EZVIZ	When you are still deciding which technology to use
SD Card vs NVR	The cost breakeven point for 1–4 cameras, the risk of silent failures, and differences in recording timelines	For 1–4 cameras, when you have not yet decided whether you need an NVR
How to Choose from 13 NVRs	A four-tier comparison of all the NVRs in the store, including which models do not have PoE and which do not include a hard drive	Once you have decided to use an NVR
How to Choose a PoE Switch	65W 5-port vs 120W 8-port, and situations where you do not need a switch at all	When the NVR has no PoE ports or not enough ports
Three Formulas for Power, Bandwidth, and Hard Drive Capacity	How to calculate the power budget, bandwidth, and hard drive capacity	When you want to calculate whether your specifications are sufficient
NVS36 36-Channel Real-World Setup	36 channels but only 4 camera ports: three power architectures and the actual capacity with 48TB	For 17+ cameras or multi-story industrial buildings
EZVIZ H8C + Reolink Switch	The real connection setup for a single camera, what you lose when mixing brands, and where recordings are stored	Only want to install one, but want PTZ
How much does CCTV for a shop cost?	Practical budget breakdown for SMEs	The boss wants a cost estimate

The other three are feature articles to read as needed:Video doorbells(7 models compared),Reolink battery cameras(No cabling possible at all),27 EZVIZ models(Already decided to use the EZVIZ ecosystem).

Step 3: The three most common wrong turns

This section is worth more than the two tables above—because we encounter these three mistakes every day.

Mistake 1: Buying the NVR first, only to discover that it doesn't provide power

NVS36 has 36 channels butzero PoE ports; EZVIZ X5S and Reolink NVS12W have none either. If you buy any of these three and don't have a switch, not a single camera will start up.

By contrast, NVS4, NVS4E, NVS8, and NVS16 come with built-in PoE, so you can connect the cameras directly. Therefore, you must confirm one thing before placing your order:Does this NVR have PoE ports?

Mistake 2: Buying the cameras first, only to discover that they are incompatible with the brand

PoE power is standardized (IEEE 802.3af/at), and any brand can supply power to them—so there is no risk here. ButNVRs are not: Using an NVR across brands relies on ONVIF/RTSP, and PTZ control and AI detection will mostly stop working.

So if you plan to use an NVR,you should choose one brand from the start, with the cameras and NVR from the same brand. Starting with cameras from Brand A and later adding an NVR from Brand B is the most common source of wasted money.

Mistake 3: Assuming a memory card can replace an NVR

One or two cameras can indeed work this way. But four cameras with memory cards provide only 3 daysof recording, while an NVR with 4TB provides 23 days—and costs even less. More insidiously, when the microSD card fails, the camera continues to operate and display video as usual;only the recording stops silently, and you won't receive any notification.

Step 4: Complete equipment lists for three common setups

Scale	NVR	Switch	Hard drive
4 x 2K cameras (residential/small shop)	NVS4-NHD (built-in 4 ports)	Not required	2–4TB purchased separately
8 x 4K cameras (two-storey shop)	NVS8-NHD (built-in 8 ports)	Not required	1 SATA + eSATA, up to 12TB
36 x 2K cameras (industrial building)	NVS36 (zero PoE)	5 x 8-port 120W	3 × 16TB

The most important point to remember:Only setups of 36 channels need a switch.For the 4-camera and 8-camera options, the NVR provides power on its own—a switch would be an unnecessary expense.

Step 5: If you only want to buy one thing

Your situation	This is all you need to buy
1 camera, with a power outlet	H8C PoE + 12V power adapter + microSD
1 camera, with only an Ethernet port	H8C PoE + PoE switch (or PoE injector)
4 cameras, brand-new installation	NVS4-NHD + hard drive + 4 PoE cameras
8 cameras, brand-new installation	NVS8-NHD (built-in 2TB) + 8 PoE cameras
No way to run cables	Reolink battery-powered camera or NVS12W (Wi-Fi NVR)

Not sure? Ask us.Tell us: ① how many cameras you want to install ② whether there is an Ethernet port at each location ③ how many days of footage you want to retain. These three answers are enough for us to determine the complete list and provide a quote.

Frequently Asked Questions

Which article should I start with?

Start with “How many cameras do you want to install?” and check the table in Step 1. For 1–2 cameras, read WiFi vs PoE; for 4 or more cameras, read the NVR buying guide.

Do I definitely need to buy a PoE switch?

Only when the NVR does not have PoE ports (NVS36, NVS12W, X5S). NVS4／NVS8／NVS16 come with built-in PoE and do not require one.

Can cameras from different brands be connected to the same NVR?

Technically, yes (ONVIF／RTSP), but pan-tilt-zoom control and AI detection will mostly be unavailable. We recommend using the same brand.

What is the cheapest recording solution?

1 camera: a microSD card. 4 cameras: NVS4-NHD + 2TB hard drive, approximately HK$1,330 (excluding cameras).

How many cameras are typically installed in Hong Kong homes?

2–6 cameras. The main entrance, hallway, and living room are the three most common locations; village houses may also add the parking area and back door.

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