Home closed-circuit TV (CCTV) systems are growing more popular as they become more affordable, and many buyers are doing the installation themselves. CCTV cameras require two wire connections to power the system, plus a 75 ohm RG-59 coax cable to send the signal. Consider purchasing Siamese cable because it has the RG-59 coax and the power wires in one easy-to-install cable. Most cameras come with a power supply with a cord which must be cut so the Siamese cable can be spliced in to provide power to the camera.
Run the Siamese cable from the camera location to your recorder or monitor.
Cut the power cord and connect the wires from the camera end of the power cord to the Siamese cable red and black wires using the butt splice connectors.
Strip the RG-59 Coax and install a BNC (British Naval Connector) to each end of the of the coax Siamese cable according to the instruction which came with the connectors.
Connect the camera coax cable to a BNC barrel and the other end of the barrel to the Siamese cable.
Connect the wires from the power supply cord to the red and black wires on the other end of the Siamese cable using butt splice connectors.
Wrap all butt spice connectors and barrel-to-BNC connections with electrical tape to keep moisture out and reduce corrosion.
Plug in the power supply and adjust your camera.
The most difficult part of wiring a CCTV camera is correctly installing the BNC connectors. Purchase a few spare connectors so you can practice. There are videos on YouTube which show how to correctly install BNC connectors. There are several types of BNC connectors and each type requires a different type of crimping tool. Do not use twist-on BNC connectors or wire nuts to make your connections; both of these parts have a high tendency to fail over time.
All of the camera voltages are considered low voltage so there is no danger of electrocution. When connecting the power wires from the Siamese cable, do not get the voltage reversed or you could damage your camera. Note that the power supply cable has two wires and one is marked with a stripe, a ridge in the insulation or some other type of marking. Always connect the marked power supply wire to the red wire in the Siamese cable and you will never mistakenly reverse the polarity of the voltage.