Power Surges

Power surges


Axis cameras are designed to resist voltage transients to a certain degree. This design depends on proper installation.

The network cable connecting the camera to a switch may pick up strong magnetic and electrical fields in its immediate proximity, leading to voltage transients propagating along the cable. Through the use of a shielded network cable (STP), the electrical energy is instead trapped by the shield, and diverted to ground without ever reaching the camera. This requires the shield to have an unbroken path to ground through the Power Sourcing Equipment (PSE), usually a Power over Ethernet switch or a midspan.

Figure 1: Always use shielded cables to protect against transients.

For this to work, it is imperative that the PSE is properly grounded. An Axis PoE midspan should always be connected to a grounded socket for the shielding to function properly.


Figure 2: A network switch with a dedicated ground terminal.

Some desktop switches (as in the image above) might not have a ground connection through the power line, in which case the switch must be grounded separately.

Always consider the entire cable path when performing the installation. If you are connecting several network cables together to reach the camera, make sure each cable and all patch panels and couplings are shielded.