Much appreciated since I had a few glasses of wine and didn't have my glasses on when I typed it out on my phone.
The last time I looked at this, this is usually done using isolated DC to DC converters which have the transformer embedded right into the substrate.. So they are still magnetically coupled..... just within a single part....
Implementation methods vary - that's one approach - but a simpler and cheaper commonly used approach uses a downconvertor with an inductor, not a transformer, therefore having a direct connection to the internal circuitry.
On the receive side obviously? Would that then require that the transmitter be isolated?
You would certainly think so, but I've seen a couple of Hikvision NVRs where the ethernet cables were at a solid -48V to ground.
Not to mention not having to deal with the issue of metallic cable between buildings, use shielded or not, grounding methods, etc.....the whole kit and kaboodle.
FWIW, the transmit power on Ubiquiti (and most other mfgs.) can be dialed way down as needed.
Unless the following document is bogus, IEEE 802.3af requires port isolation from the body or case. There are 2 types of isolation, one where all the ports are isolated as a group, the other where every port is isolated individually. See "Electrical Isolation" near the end of the document.
Since our cameras use nominal 48 vole POE, I'll point out that the 6-inch rule is only for landscape and irrigation control wiring not more that 30 volts. Otherwise it's 6 inches with heavy metal conduit, 18 inches with PVC conduit, or 24 inches for direct burial. This is from NEC table 300.5(A). Is there an exception somewhere for network cables that I can't find? That would be nice.
True, but my assumption was he was trying to go building to building here where each had their own power/ground. POE doesn't necessarily apply in this case...
store.ui.com
It's been that way for about 2 years.
I can't offhand quote chapter and verse, but there's an exception to the burial and some other NEC rules that says (in my words) "utilities can do whatever they want to".
To some degree, yes. But like most things, there are exceptions, depending who you are. In this case, it's the railroad...they're older than dirt and pretty much do what they want to and when they want to do it.
Here in NC Spectrum uses a special machine to bury the cable so tree roots aren't a problem. I have seen AT&T hand bury fiber cable the way you described.Spectrum buries their network cables from the outside of the house to the pedestal by splitting the ground with a shovel then pushing the wire down. Usually it's 3 to 6 inches and this is common practice here in Florida where we have high sand content. Mine runs about 120 feet but you can see how they bury the cable when they don't feel like messing with tree roots.
View attachment 180408
And not that low voltage lighting wire is a communication protocol but it's 12-15VAC and typically is just thrown on the ground and maybe mulch or leaves covers it slightly over the years. That's how mine has been for 30+ years.
Before we moved into our house Spectrum was the provider for tv, internet etc. They had their ground tied to the natural gas line coming into the house about a food under grade.........Spectrum buries their network cables from the outside of the house to the pedestal by splitting the ground with a shovel then pushing the wire down. Usually it's 3 to 6 inches and this is common practice here in Florida where we have high sand content. Mine runs about 120 feet but you can see how they bury the cable when they don't feel like messing with tree roots.
View attachment 180408
And not that low voltage lighting wire is a communication protocol but it's 12-15VAC and typically is just thrown on the ground and maybe mulch or leaves covers it slightly over the years. That's how mine has been for 30+ years.
