CCTV Power Supply

As the name implies, a CCTV power supply provides electric power to a closed-circuit television camera.

Since many users install more than one camera, one CCTV power supply may distribute power to a number of cameras. This saves on running standard house or office wiring and installing a power bar and single-camera power source for each camera.

AC or DC?

Some CCTV cameras need AC, some need DC, and some are dual-power.

The two popular choices are: 24V (volt) AC; 12V DC.

Many power supply units can be switched to accept either North American 120V or European 240V power.

How Many Cameras?

Some power supply units simply have one output channel, supplying the 12V DC to a single camera.

Other units support multiple cameras. A small power supply may have only four power channels. It is easy to find a supply with 18 channels. Each channel can power one camera.

How Much Power?

One CCTV power supply may draw as little as 100mA, or one-tenth of an ampere. Dome security cameras may draw 300mA.

A typical power supply will provide 500mA (one-half ampere) per channel. So a four-channel supply will draw 2 amperes, whereas an 18-channel supply will draw 9 amperes from the building's wiring.

Infra-red cameras may require more power. Some manufacturers provide 1-ampere per channel to cover the most demanding cameras.

Each channel should have its own fuse or breaker, so a short circuit to one camera does not interfere with the others.

Where to Install?

The CCTV power supply should be in a secure location, so thieves cannot disable all its cameras by pulling one plug.

If the security installation uses a central DVR (Digital Video Recorder) to "tape" all the cameras, it makes sense to install the power supply there too.

In Case of Emergency

A serious security installation needs some protection from external power outages. Even a battery-based UPS (Uninterruptible Power Supply) can keep the CCTV power supply running - and the cameras - running for a limited time.
Equally important is a UPS for the recorder and for the real-time monitoring station.

Comparison Shopping

The lack of one or more of these features may indicate low quality or a potential problem.

The output power should be "regulated." This means that the output stays at a constant voltage even if the input fluctuates. The UPS might provide power regulation, so this might be a reasonable trade-off.

Each output should have a fuse (or breaker) to protect against overloads or short circuits.

The unit should remain cool under normal operation. Heating may indicate that the wires are a smaller gauge. That is a cost saving to the manufactures, but lessens the service life to the customer.

Any cooling should be by free air convection.

Many units are built to accept any input voltage from 100V to 240V AC. This may not matter at one installation, but it may be a symptom of other cost-cutting.

Look for high efficiency. These units will run day and night, so they should be as efficient as possible.

Excessive noise is a sign of inefficiency, and perhaps of poor design.

If it is worth installing a video security system, then it is certainly worth installing a high-quality CCTV power supply.