What Voltage Do CCTV Cameras Need
Analogue and AHD cameras run on 12 V DC — this is the de facto standard for most budget and mid-range units. A portion of IP cameras also operate at 12 V, while higher-end dome and PTZ models commonly require 24 V AC or DC. Before selecting a power supply, check the camera spec sheet for both voltage level and current type (AC/DC) — they are different devices.
Why Camera Power Draw Increases in Winter
The IR illuminator is the hungriest component in any camera. Below freezing, IR LED efficiency drops, and the illuminator controller automatically raises current to maintain image quality at night. In practice, a camera with IR illuminators can draw 20–40 % more than the rated value measured in a warm lab. A power supply sized too tightly will trip its protection circuit regularly in winter, taking the system offline at the worst possible time. The rule: add at least 25–30 % headroom above the combined rated draw of all cameras.
Voltage Drop on Long Cable Runs
Cable is not an ideal conductor. The longer the cable and thinner the gauge, the more voltage is lost to resistive drop. Cameras located 50–80 m from the power supply can see a drop of 0.5–1.5 V. Most cameras tolerate 10.5–13.5 V, but at the low end recording quality and reliability suffer.
The solution is an enclosed LRS-series Mean Well supply with output voltage trim (Vadj potentiometer on the case). Set the output to 12.5–12.8 V and the far end of the longest run will see a stable 12.0–12.3 V. DIN-rail HDR and NDR models do not have this trim — for a distribution cabinet with long cable runs, choose an LRS in a separate enclosure rather than HDR.
How Many Cameras Can One Power Supply Support
Quick calculation: sum the rated current draw of all cameras, add 30 % headroom for IR and temperature, then select a model with a nominal current rating at least equal to that result.
| Model | Current, A | Power, W | Cameras at 500 mA each (30% margin) | Mounting |
|---|---|---|---|---|
| LRS-50-12 | 4.2 | 50 | up to 6 | Enclosed |
| LRS-75-12 | 6.0 | 72 | up to 9 | Enclosed |
| LRS-100-12 | 8.5 | 102 | up to 13 | Enclosed |
| MDR-40-12 | 3.33 | 40 | up to 5 | DIN rail |
| HDR-60-12 | 4.5 | 60 | up to 6 | DIN rail |
| NDR-75-12 | 6.3 | 75 | up to 9 | DIN rail |
If the system lives in a distribution cabinet, DIN-rail NDR or HDR is more convenient. If the power supply sits in a separate enclosure alongside the DVR/NVR, choose an LRS with its own housing and Vadj trim.
24 V IP Cameras: When and What to Choose
Some mid-to-high-end PTZ and dome cameras run on 24 V DC. Voltage drop is still a concern, and PTZ cameras can draw 1.5–2 A each. For this segment: LRS-100-24 (4.5 A / 108 W) or NDR-120-24 (5 A / 120 W) for cabinet installation.
How to Calculate Power Requirements
A detailed calculation covering cable type, gauge, and run length is in the article How to Calculate Power Supply Wattage. The quick CCTV field formula:
- Count cameras by type.
- For each type, use the rated draw with IR at full brightness.
- Sum total current.
- Add 30 % — this is your minimum nominal rating.
- Select the next standard model size up.
LRS vs HDR and NDR: Cabinet vs Enclosure
LRS is an enclosed format with its own metal housing — mounts with screws or on DIN via adapter. It has Vadj trim, which is essential for long cable runs. HDR and NDR are native DIN-rail designs, convenient alongside MCBs and relays. HDR lacks PFC and suits loads up to 60 W. NDR-75/120 covers higher DIN-rail power without PFC. For CCTV cabinets with no harmonic distortion requirements, PFC is unnecessary — choose HDR or NDR and avoid paying for features you do not need.
All models are genuine Mean Well products with warranty, shipped from stock. Full range in the Industrial Power Supplies section; Mean Well lineup at Mean Well. Not sure which model fits? Send us your camera list and cable lengths — we will select the right supply within one working day.
