CCTV installation is a specialist trade and one that is best reserved for security industry professionals. While many general electricians may offer this as a service, they simply do not have the specific knowledge and experience to offer the same level of expertise.
As well as the physical installation of the equipment, there are many factors to consider such as optimum positioning of the cameras, set up of the DVR, integration with other security measures such as intruder alarm and the settings of the system itself.
We also know the market better and can make informed recommendations on the specifications of the system such as whether it should be IP or analogue HD, how many cameras you need and where to put them to minimise interference from weather conditions and full training on how to get the most from the system.