Security Surveillance Power
CCTV adapters, 12V/24V PSU, UPS backup
CCTV Power
A practical guide to powering surveillance cameras — 12V/24V DC adapters, centralized multi-output PSUs, PoE for IP cameras, and UPS backup that keeps recorders online.
How surveillance cameras are powered
Most analog and HD-over-Coax cameras run on 12V DC or 24V AC from a plug-in adapter or a centralized power box. IP cameras can take the same low-voltage DC, but the dominant modern method is PoE (Power over Ethernet) — delivering both data and power over a single Cat5e/Cat6 cable per IEEE 802.3af/at/bt. Choosing between them comes down to camera count, cable distance, and whether you need the recorder to stay up during a power outage.
12V DC vs 24V AC for CCTV
12V DC is the default for bullet, dome and turret cameras and matches the 12V/24V CCTV adapters most installers stock. 24V AC is preferred on longer runs because it tolerates more voltage drop and is safer to run in conduit for PTZ and heater-equipped cameras. Rule of thumb: keep 12V runs under ~30 m (100 ft), or step up to 24V AC / a centralized supply for longer distances.
Centralized power: multi-output PSU / power box
A multi-output CCTV power box (typically 12V 10A–20A, 8/16/24 fused channels) feeds an entire camera bank from one location next to the NVR. Benefits: one fused supply to service, individual channel fuses that isolate a fault, and a single UPS point that protects every camera at once. The trade-off is a thicker home-run of cables back to the box; plan trunking accordingly.
PoE for IP cameras
PoE removes the local power brick entirely. 802.3af delivers 15.4 W (most fixed IP domes), 802.3at ("PoE+") 30 W (PTZ, heaters), and 802.3bt ("PoE++") up to 60–90 W (mini-NVRs, pan-tilt-zoom with wipers). Maximum structured-cable distance is 100 m; beyond that use a midspan injector or a PoE extender / PoE switch. PoE simplifies audits and centralizes backup power at the switch.
Backup power (UPS) for surveillance
A surveillance system is only as reliable as its uptime. A line-interactive or online UPS on the NVR and PoE switch keeps recording through grid dips and short outages, and a LiFePO4 UPS battery extends runtime far beyond lead-acid for sites with unstable mains. Size the UPS to the NVR + switch + camera load, not just the recorder.
Wire gauge, distance and voltage drop
Voltage drop is the #1 cause of night-vision "ghosting" and camera reboots. Use thicker cable on longer runs:
| Distance (one-way) | 12V camera load | Recommended conductor |
|---|---|---|
| ≤ 15 m | ≤ 1 A | 18 AWG (0.75 mm²) |
| 15–30 m | ≤ 1 A | 16 AWG (1.0 mm²) |
| 30–60 m | ≤ 1 A | 14 AWG (1.5 mm²) or step to 24V |
| > 60 m | any | 24V AC or local PoE / midspan |
Keep end-of-line voltage within ±10% of nominal (10.8–13.2 V for a 12V cam). When in doubt, measure under load before final termination.
CCTV power selection checklist
- Count cameras and note each one's rated voltage/current (printed on the label).
- Decide topology: distributed adapters (simple, per-camera) vs centralized fused box (easier service, one backup point) vs PoE (cleanest for IP).
- Add 20–30% headroom to total wattage for inrush and future cameras.
- Size cable for voltage drop; switch to 24V or PoE on long runs.
- Put one UPS on the NVR + switch so recording survives outages.
- Verify certifications for the market (CE for EU, UL for North America).
Related products
CCTV Power FAQ
What voltage do CCTV cameras use — 12V DC or 24V AC?
Most fixed cameras use 12V DC; PTZ and long-run installs often use 24V AC. Always match the camera label — mixing 12V and 24V on the same power box will damage cameras.
How far can I run 12V CCTV cable before voltage drop?
Keep 12V DC under ~30 m (100 ft) with 18 AWG, or use 16/14 AWG for longer runs. Beyond ~60 m, switch to 24V AC or PoE to avoid night-vision artifacts and camera reboots.
Is PoE enough to power my IP cameras?
For fixed IP domes, 802.3af (15.4 W) is enough. PTZ or heated cameras need 802.3at (30 W); pan-tilt-zoom with wipers may need 802.3bt (60–90 W). The total PoE budget is set by the switch.
Do I need backup power (UPS) for a surveillance system?
Strongly recommended. A UPS on the NVR and PoE switch keeps recording through outages; a LiFePO4 UPS battery extends runtime well beyond lead-acid for unstable grids.
Centralized power box vs individual adapters — which is better?
A centralized fused box is easier to service and backs up every camera from one UPS point, at the cost of home-run cabling. Distributed adapters are simpler per camera but harder to back up centrally. Pick by install size.
Need a Custom Power Solution?
37 senior R&D engineers. OEM/ODM from 500 units. Samples in 3-7 days.
Get a Quote WhatsApp Us