PT-4 power leads are typically used to connect the 18 gauge pair of power cable to RG-59 Siamese cable to a security cameras DC power plug input. PT-4 power leads can also be used with pro box style security cameras that do not typically have a DC power plug attached to them. Box security cameras typically have screw terminals for a positive and negative wire connection. If you are using plug and play cables, you can attach a PT-4 to the cameras power terminals for a clean connection to your plug and play cables. You can see an
example wiring diagram here. PT-4s provide 1 foot of cable and a male connector for CCTV Camera power. The diameter of the connector is 2.1mm which is the standard size used for plug and play cables.
The above diagram show how PT-4 leads are typically used when installing CCTV cameras with
premade Siamese coax cable. The
AHD-BL5H HD CCTV camera used in this example is a dual voltage camera, which means that it may accept a 12V DC or 24VAC power supply. Dual voltage security cameras almost always have a terminal blog to connect a power source to, instead of the standard 2.1mm female plug that most 12V DC only cameras have. The PT-4 is used to connect a the power cable on the pre-made Siamese cable to the camera. The raw cable end of the PT-4 attaches to the screw terminal block on the camera and the 2.1mm male connects to the female side of the Siamese cables.
In this example, a multi-channel power supply box is used (on the DVR end). So, a
PT-3 female power lead is used to connect the other end of the Siamese cable to the terminal block of the power supply box.
Using PT-4 Power Leads with RG59 Coax Cable
If you plan to use individual power transformers (instead of a multi-camera power supply box) with RG59 Siamese coax cable, you must attach a
PT-4 power cable lead on the DVR side of the cable run. This allows the 18/2 power cable to attach to the 2.1mm female power lead of the power transformer.
Here is a complete security camera system installation diagram that uses a RG59 cable with an individual power transformer powering the camera from the DVR side of the cable run. You may click on the image for a higher resolution view.
- The RG59 Siamese cable is cut to the exact length required.
- On the camera side of the cable, a BNC connector is attached to the RG59 coax and a PT-3 power lead is attached to the 18/2 power cable.
- On the DVR side, a BNC connector allows the coax cable to connect to the video input of the DVR and PT-4 is attached to the 18/2 power wire with B connectors so that the power cable can attach to a individual power transformer - which has a 2.1mm female power connector.
Mr. 
