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CCTV Buyer's Guide To Power Supply Units

CCTV Buyers Guide Part 2: PSUs

    In this section:

  1. A B C
  2. What To Avoid
  3. 60 Second Guide
  4. The Facts
  5. Related Guides
  6. Did You Know?
  7. Jargon Buster
  8. In The News
  9. Have Your Say

Powering cameras and recording equipment in the right way is critical to a lasting & quality CCTV installation. Get it wrong and you could waste hours trying to correct voltage drop issues and interference. Our CCTV Buying Guide helps point you in the right direction…

Download as PDF


A B C to go for...

Rack Mount PSU

A quality regulated PSU is essential to get the maximum life span from your CCTV equipment. Overvoltage will eventually kill a camera.
Be smart when choosing which voltage to go for. 24V AC devices require less current than 12V DC so are great where long cable run exist.
Choose a multi-port and fused power supply unit, if 1 camera cable gets struck by lightning that fuse will blow but the other cameras should remain unaffected.


12V DC Plug
  • Choosing a PSU with insufficient capacity. A heated housing switching on in cold weather or IR LEDs switching on at dusk can easily double current consumption.
  • Risking shorts by using pre-formed DC leads or Zulug DC connectors.
  • Alarm power supplies, they are 13.8V and will eventually blow up a 12V dc camera even if not on day 1.
  • Power interruption problems by installing a back up UPS for your CCTV system.

60 Second Guide

60 Second guide
  1. Select a style according to the installation space.
  2. Select a voltage according to the installation framework.
  3. Calculate the total consumption of your equipment.
  4. Take care when running out your cable not to stretch or bend the run to excess.
  5. Multiply by 1.5 to calculate Amperage and allow for good operating headroom.
  6. Select the PSU(s) that fits the job the best.

The Facts

The Facts

A 12V DC CCTV camera will usually need more than 10V to operate, any less can result in a loss of picture completely or poor images at night. Basic CAT5 and alarm cables will struggle to supply this over 100 metres runs.

Related CCTV Tips:

How to fit CCTV

Did You Know

Did you know?

"TV Pick Up" is a common phenomenon where demand for power significantly surges during the advert breaks of popular TV shows or televised sports events. At half time when England played Slovenia in the 2010 World Cup a surge of nearly 1300 MegaWatts occurred, the equivalent of half a million kettles being boiled.*

Source: *National Grid press release

Jargon Buster

Jargon Buster

AC - (Alternating Current) Used to indicate that voltage or current in a circuit that is alternating in polarity at a set frequency, often 50 or 60 Hz.
DC - (Direct Current) Electrical current which flows in one direction.
Wattage - This a form of power measurement so to calculate what rating of PSU you need when only have the Wattage spec of a DC item, as a rough guide simply divide the voltage by the watts eg, 12/24 = 0.5A or 500mA.

Read the full CCTV Jargon Buster here

In The News

In the News

In February 2016, the USA adopted the new Level VI energy efficient regulation designed to conserve power usage in both consumer and industrial products. It not only requires manufacturers to improve energy consumption on devices when active but also in no-load operation. The EU is expected to follow suit within months. ** For compliant PSUs, see here.

Source: **EPSnews.com

...and Finally

And Finally

This guide plus other handy CCTV installation tips can be downloaded FREE from our CCTV Installer's Help Zone.

Have Your SayTell us what you look for when selecting a CCTV product in our 30 second CCTV survey

Next Time: CCTV Buyer's Guide Part 3: LCD screens

CCTV Blog: Check out our CCTV industry expert's blog here!

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