What Size PoE Switch for 8 CCTV Cameras? UK Guide 2026

Eight cameras need at least an 8-port PoE switch, but the total PoE budget decides whether it actually works, not the port count. Add up each camera's maximum draw from its datasheet, add 20-30% headroom, and choose a switch whose total budget clears that figure, ideally with a spare or uplink port. As an illustration, if you assume 8 cameras at about 8 W each (64 W), you'd need roughly 77-83 W of total budget, so a switch rated well below that will fail once every camera is running, even if it has enough ports.

Eight PoE ports plus a spare or uplink port, and a total power budget comfortably above your cameras' combined draw plus 20-30% headroom.

Port count is the easy half. Eight cameras need eight PoE ports, and the link to your NVR or network shouldn't take one of them, so look for a switch with a separate uplink. If you expect to add cameras later, step up to a 16-port rather than filling the switch on day one.

Total budget is where undersized switches fail, because all ports share one pool of power. The IEEE 802.3af standard allows up to 15.4 W per port (about 12.95 W at the camera after cable loss) and 802.3at up to 30 W (about 25.5 W). The per-port ceiling is not the budget: some 8-port switches pair that 30 W ceiling with a total of only 110 W, so eight cameras fit only if their combined datasheet draw, plus headroom, stays within that figure.

To size it, add each camera's datasheet draw, then multiply by 1.2 to 1.3, in keeping with Techlogics's advice never to plan for 100% PoE utilisation. If all you know is the class, eight 802.3af cameras at the 15.4 W limit come to 123.2 W, so roughly 148 W to 160 W with headroom, which is already beyond a 110 W switch. Many cameras draw less than their class limit, which is why a Hikvision PoE camera or any other brand should be sized from its own datasheet. Edge AI Stack puts most 8-camera builds at 120-180 W once surge, cable loss and headroom are counted.

One PTZ, a camera with long-range IR beyond 50 m, or a heated outdoor unit needs 802.3at and moves the total noticeably.

Cable choice, system layout and NVR selection are covered in our PoE CCTV system, Cat6 and Cat5e guides.

How do you calculate the real PoE budget?

Add up each camera's maximum datasheet draw, apply 20-30% headroom, and compare the result with the switch's total PoE budget, not its per-port rating.

1. Take the maximum power figure from each camera's datasheet, not the typical one.
2. Add all eight together.
3. Multiply by 1.2 to 1.3.
4. Check the answer against the switch's total budget.

Worked example

Assuming each camera draws about 8 W (an illustrative figure, not a datasheet value):

8 cameras × 8 W = 64 W 64 W × 1.2 to 1.3 = roughly 77-83 W required budget

Real maximum draw is often higher than 8 W, especially on cameras with strong IR, motorised zoom or heaters. Swap in your own datasheet figures before buying.

Why 120 W is comfortable

A 120 W-class switch clears 77-83 W with room to spare. That margin matters because IR LEDs draw more at night, heaters can add load in cold weather, and cameras may pull a brief surge when they boot together. Planning tools such as the Techlogics PoE calculator advise against ever planning for 100% utilisation.

Cable loss on long runs

Port output is not what reaches the camera. Per PATRONUM's PoE guide, 802.3af ports deliver up to 15.4 W but about 12.95 W arrives at the camera, and 802.3at ports deliver up to 30 W but about 25.5 W arrives. The gap grows with run length, so on runs approaching 100 m, budget for the switch supplying more than the cameras use.

Should you choose 802.3af or 802.3at ports?

Choose 802.3af for most fixed cameras, and 802.3at where a camera has powerful IR, motorised zoom, heaters or PTZ.

IEEE 802.3af (PoE) supplies up to 15.4 W per port and 802.3at (PoE+) up to 30 W, and slightly less reaches the camera because of cable loss. The PoE power budget calculator adds that loss for your run length, plus a safety margin, to the camera draw. IEEE 802.3bt (up to 60 or 90 W) is typically reserved for high-power applications such as PTZ, so most eight-camera sites will not need it.

Reading the datasheet

The per-port rating and the total budget are separate lines, and the second one limits you. The figures below are a specification example for working the arithmetic, not a recommendation of a particular model: 8 PoE ports, one RJ45 uplink, one SFP uplink, 30 W per port and a total budget of about 110 W.

• Demand if every port drew its maximum: 8 × 30 W = 240 W.
• Supply: about 110 W, shared across all ports.
• Average per port: 110 W ÷ 8 ≈ 13.75 W, which is below the 15.4 W af ceiling. Eight cameras each drawing the full af maximum would need 8 × 15.4 W = 123.2 W, so they would not fit.
• What does fit: eight cameras work only if their combined datasheet draw, with your planned headroom, stays within 110 W. Three cameras at a full 30 W take 90 W (3 × 30 W) and leave just 20 W for the other five.

So "30 W per port" tells you what one port can deliver, not what eight can draw together. For a mixed site, such as seven fixed cameras and one PTZ, add up each camera's real draw rather than its port class.

Which PoE CCTV camera? Whichever one the camera's own datasheet says will fit your port class. That applies equally to a Hikvision PoE camera or a PTZ.

Is an 8-port switch enough, or should you go to 10 or 16 ports?

Eight cameras fill an 8-port switch completely, so the NVR needs somewhere else to plug in, and an 8+1+1 layout solves that.

That layout gives you eight PoE ports for cameras plus two uplinks, one Gigabit RJ45 and one SFP fibre. Hikvision's DS-3E0510P-E is a typical example. The uplinks take the NVR or the link to your router, so no camera port is lost.

Watts matter more than ports

Port count says nothing about power. The DS-3E0510P-E allows up to 30 W per port but only 110 W across the whole switch, so eight ports at full draw would ask for 240 W it cannot give. Moving to 10 or 16 ports without a bigger budget just gives you sockets you can't power. Read the total wattage on the spec sheet before you compare port counts.

Planning for later

If a ninth or tenth camera is likely, a 10-port or 16-port unit saves a second purchase. Pick it on the budget figure first and the port count second.

A spare port is also the obvious place for a PTZ camera or an access point. A PTZ typically needs 802.3at, which supplies up to 30 W per port, according to Patronum's PoE guide. Add that draw to your calculation now rather than discovering the shortfall later.

Unmanaged or managed?

An unmanaged switch is plug-and-play and is enough for most 8-camera systems. Managed models only earn their extra cost if you need to separate camera traffic from an office network or monitor individual ports. For a standalone set of eight cameras and an NVR, you can usually skip them.

Why does PoE budget, not port count, usually cause the failure?

The ports share one power supply, so eight sockets don't guarantee the switch can feed eight cameras at full draw simultaneously. Some 8-port PoE+ switches allow 30 W per port but list a total budget of only 110 W to 120 W, so the ports can promise more than the supply can deliver.

What overload tends to look like

These are typical patterns, not guaranteed ones:

• Cameras reboot or drop around dusk, when infrared typically switches on and draw rises.
• The last camera plugged in never powers up, because the budget is already spent.
• Everything looks fine in daylight but becomes unstable at night.

Cold weather can make this worse. The Techlogics calculator warns against planning for 100% PoE utilisation, and cold weather is one of its reasons. Heated housings also raise draw, and Patronum notes that heating, long-range IR (over 50 m), motorised zoom and PTZ typically need 802.3at rather than 802.3af.

How to check

Take each camera's real draw from its datasheet, whether it's a Hikvision PoE camera or another make, and add them up. Then multiply by 1.2 to 1.3 to leave a 20–30% margin and compare the result with the switch's total budget, not its port count. As an illustration, eight cameras drawing 10 W each is 80 W, which points to a budget of roughly 96 W to 104 W or more. One 8-camera sizing guide, Edge AI Stack, puts typical real-world requirements at around 120–180 W once surge, cable loss and headroom are counted.

Fix ladder

1. Move to a switch with a higher total budget.
2. Reduce the number of high-draw cameras (PTZ, heated, long-range IR) on that one switch.
3. Split the load across two switches.

Powering a camera without a switch

A single-port PoE injector can power one camera, and many recorders have PoE ports built in. Recorder choice is a separate decision, covered in the NVR article.