I have one 15’ cable run through a wall and then behind a baseboard for about 6 feet. I’m not concerned about it being a fire hazard being low voltage DC. I’m not an electrician, but I would not think it would be against code given that homes are wired with Cat 5 cable without any additional shielding.
You have to be careful that you don’t have too much voltage drop on a long cable run. The larger the wire gauge, the less voltage drop. The monoprice cables here:
are 22AWG (lower number, thicker wire), which I believe is sufficient (but perhaps barely) for 15 feet (and they’re on sale for $1.85 right now).
Here’s a voltage drop calculator:
For the 15’ monoprice cable, it works out to .24V drop at .5 Amps (see attached). Just a guess on the amperage: the included power block is 1 Amp and is supposed to be able to handle 2 or 3 cameras, so I used .5 amps for this calc.
Bottom line: if you go longer than 15 feet, make sure the cable you use has sufficient gauge on the power wires for the length of run.
