@ Westrom
I spoke in detail with Elk engineers directly with this. I had a project that went well beyond the 4K 485 distance and the M1 was on the short list for proposed panel solutions.
Bringing 485 into a FOC and then from another FOC back to copper adds latency and a few other issues and Elk themselves said it will not work properly and the M1 will not be happy when it polls the devices. The latency will also slow down the bus and introduce some other issues.
That said, I use FOC's all the time and bend data to all different formats and media, have I tried it on an M1, no, but speaking with the engineers and my application for a multi million dollar property, it was not an option. (BTW, the house is on Zillow at the moment on 20 acres for 62 million).
I didn't bring up the noise point, UTP and STP should address this, barring any other consideration, however ferrites and optical isolation can be used to help mitigate the introduction of RF or other interference besides basic noise. Optical isolation does not mean the installation or running of fiber or FOC's.
LV cabling in the same raceway as HV is perfectly legal and acceptable by code and perfectly safe, the only caveat is what I mentioned....the insulation must be rated the minimum for the highest voltage that is within the raceway. IE: if you have 600V THWN in the conduit, the LV cabling is not required to be separated as long as it's jacket carries the same or greater voltage rating. There is no requirement for fusing, overcurrent protection, etc. because when the cabling leaves the raceway, it is not connected to a system that operates on HV. That is also assuming the insulation of all the cables is intact and there is no damage while pulling the cabling in. Once the cabling leaves the raceway into an enclosure, handhold, etc. at the earliest possible location, the cabling should be separated.
I've had to perform this dance many times....CCTV cameras on lighting poles, installed after the asphalt/concrete is down and cutting is not an option or budgeted....the "oops" factor of installing contacts and comm's out to gates and operators...How about elevator traveler cables (they have 600V and LV in the same cable) they end up in a enclosure at both ends that has 600V and lower and LV..... like I said, the cabling is out there if you look for it and it can be installed and still be compliant, but are the materials and methods going to be known at the big box stores, nope.
