What exactly do you mean by running an extra cable? As in run 2x cat lines to each camera?
Yes, especially if this is a very difficult location to run the Ethernet cable. Doing so allows you to grow and add on in the future and saves you time later.
In the worst case scenario the cable can be repurposed to power other devices such as microphone, speaker, lights, sensors.
Let’s just assume you say you didn’t have enough cable on site. Worst case scenario is you run a (Pull String) during the first pull.
With the pull string in place it doesn’t matter you didn’t run the second line. Because you can do so later when it’s convenient or finances are more available.
It should be noted that (IF) you forego the shielded cable and live in a lightning prone area. Do NOT coil your service line next to the camera and in stead leave enough on the other end for a service loop.
If you have complete access where the camera is you can simply secure 2-5 feet of extra cable higher up in the rafters in a (U) shape. Secure the extra cable just with painters tape as it’s easily pulled apart.
Coiled wire is / will act like an induction coil (magnet) when energized. Lightning will induce EMF into the coiled wire resulting in a really bad day for everyone!
Lastly, some tips that I hope will benefit you in the future.
Marking: Label each end of the cable with a sharpie using alpha numeric values. Mark the cable on both ends at two foot intervals. Follow up with the painters tape wrap it around a few times and mark what ever you had in sharpie.
Take clear tape and wrap the painters tape to protect the ink.
The above is the cheapest DIY method to mark cables. In the professional world it’s sharpie -> heat shrink label - Zip Tag.
As it relates to RJ45 connectors I know it’s all the rage to use pass through connectors as it’s easier to see the cable order.
But I would encourage you to purchase dead end connectors that use a (Load Bar) which makes it just as easy to confirm the wire placement.
In all cases you must use dielectric grease especially if you use pass through connectors as the end of the copper will oxidize quickly and short out the camera / port / switch!
Always squeeze a small drop into the connector as well. This will assure when the pins are pressed into the cable there’s no air gap to oxidize the copper.
