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 shows 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 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 an 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 an individual power transformer - which has a 2.1mm female power connector.