Although the cable used for digital video security systems does not carry a high voltage charge, coax surge protection is still required to protect your system from lightening and even overzealous power outages, and power surges.  If a surge makes its way to the camera or to the DVR your system could be destroyed.

While power outages and other non-lightening power surges are highly irregular for digital video security camera systems, coax surge protection is needed much more often, especially if you have outdoor cameras that could be a target for a random lightening bolt hit.