A switch with enough ports but not enough watts is the most common fault on IP camera projects. Cameras drop at night when infrared switches on — exactly when you need them.
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Uplink ports are extra and not counted. Device power per IEEE 802.3 at the device; 16% cable and conversion loss added back; 20% headroom. PTZ assumed 25 W, terminals 12 W, phones/APs 8 W — check datasheets.
Ports for every device plus uplink and spare, and a budget above the total draw.
Solid copper, not CCA. Copper-clad aluminium drops voltage and fails PoE on long runs.
One UPS on the switch keeps every PoE camera alive — cheaper than a UPS per camera.
Ventilated. A PoE switch at full load runs hot.
For runs beyond 100 m.
Between buildings, and anywhere a run crosses power cables for a long stretch.
VLANs keep cameras off the office network.
The honest trade-offs.
| Consideration | PoE 802.3af | PoE+ 802.3at | PoE++ 802.3bt |
|---|---|---|---|
| Power at the switch port | 15.4 W | 30 W | 60–90 W |
| Power at the device | 12.95 W | 25.5 W | 51–71.3 W |
| Typical devices | Fixed cameras, phones | PTZ, face terminals, APs | Large PTZ, heaters, displays |
| Maximum cable run | 100 m | 100 m | 100 m |
Every one has cost a real project real money.
Sixteen ports on a switch with a 120 W budget cannot power sixteen 8 W cameras at night.
Do this: Add up device maximums, add 20%, compare with the budget.
Copper-clad aluminium is cheaper and fails on long PoE runs.
Do this: Specify solid copper Cat6 and check the box.
Ethernet stops at 100 m, PoE or not.
Do this: Add an extender or fibre.
One power cut drops every camera.
Do this: A UPS on the switch covers them all.
A PTZ that boots then reboots is usually underpowered.
Do this: Put PTZs on PoE+ ports.
Heavy video traffic slows the office.
Do this: Separate VLAN or a dedicated switch.
Rules we apply on every installation. Share this with your installer.
A camera's infrared LEDs and any heater switch on at dusk, raising its draw. Size the switch on the datasheet maximum, or cameras reboot at night — when you need them most.
A PoE switch near its full budget runs hot, and heat shortens its life. The calculator adds 20% on top of the device total.
Dahua puts the PoE budget in the model: PFS3110-8P-96 has 96 W, PFS4226-24ET-240 has 240 W. It is the fastest way to check a quotation.
Port 7 on the switch should be Camera 7 on the drawing. Unlabelled runs turn a ten-minute fault into an afternoon.
Sixteen 4 MP cameras on H.265 need roughly 30–50 Mbps to the NVR. A 100 Mbps uplink runs close to its limit and drops frames under motion.
Outdoor cameras bring lightning-induced surges back along the cable. An earthed rack and surge protection on outdoor runs protect every port.
The network is where CCTV projects quietly fail. Four questions, in this order.
Copper-clad aluminium has higher resistance, runs hot under PoE load, and fails progressively. Solid copper only — we stock both, and we will tell you which is which.
IR illumination raises consumption after dark. A switch sized in daylight drops cameras every night at dusk.
Leave 25% headroom. No headroom means no tolerance for a marginal cable or a failing camera drawing more than it should.
One misbehaving camera can saturate the segment. Separate the VLANs or accept that a camera fault becomes an office outage.
It carries surge between structures. Use fibre, and it solves the distance problem at the same time.
A recorder on UPS with the switch unprotected records nothing during an outage. Protect the whole path, not just the recorder.
Port count, PoE power budget and cable distance decide the switch. Nothing else matters as much.
Four to eight PoE ports, with enough power budget for IR cameras at night when draw peaks.
Every product above is one DigiMark Solution imports, stocks and warrants. Pricing is quotation-based and depends on quantity and configuration — request a quotation or ask on WhatsApp.
What a network BOQ must state for quotations to be comparable.
| Sector | What to specify | Typical scale | The clause bidders exploit |
|---|---|---|---|
| Factory / industrial | Total PoE budget in watts, not just port count; IP-rated enclosures; surge protection; fibre between blocks | 50–300 cameras | State the night-time power figure — it is the number that matters |
| Corporate / office | VLAN separation from office LAN; managed switches; rack-mount form factor | 20–100 cameras | Specify managed, or you will be quoted unmanaged and the separation requirement is silently dropped |
| Government / defence | Managed and auditable; separate physical network where required; surge and lightning protection | 100+ cameras | Physical separation versus VLAN separation is a security decision — state which |
| Hospital | Redundant uplinks; UPS on all network equipment; no single point of failure on critical corridors | 50–200 cameras | Specify UPS runtime for the switches, not only the recorder |
| Campus / multi-building | Fibre backbone; core routing device; per-building access switches | Varies widely | Give the inter-building distances in the tender or every bidder will guess differently |
We will size the switch, budget and UPS.