Yes, I agree with you. 2-3" is very likely. Sometimes I can only have 1" the most. So far we use only the shielded ethernet cable. Some technicians find it very hard to crimp them, lol. And we dont have any issues with noise. Do you place the ethernet cable and power cable in the same trunking? Or rather is there any standard (allows or against) it? So far, we place them in the same trunking and they work. I know this is just marginally reasonable, worried that there are standards forbid it (placing ethernet and power cable in the same trunking).