I'm going to be installing an outdoor camera mounted under the eave of my parents' house. I am under the impression I should use shielded cable because static can build up on the camera and damage the switch. Yes, I know I need to use shielded connectors and ground the switch. Am I right? What's the best practice? The internet is all over the place on when and how you should use shielded cable.

All I know is I installed an AP in a friend's gazebo using unshielded cable and after a while it wouldn't connect at 1 Gbps. Plugging it into a different switch port works for a while and then it drops back to 100Mbps. I have reterminated the cable a few times. I also installed an outdoor AP at my parents' with unshielded cable, and it works fine. I installed one at my house with shielded cable, and it works fine.

What is the best practice?

I'm not aware of any issues with static buildup on devices. If you're using shielded cable, you should use shielded connectors and ground the cable.

My guess, without seeing pictures, with that one install is that water is wicking down the cable somewhere and damaging the switch - EMI interference wouldn't be resolved by plugging it into another port.

Yep, I would use the shielded connectors and connect the drain wire on both ends. Plugging into the switch connects the shield to the switch ground.

The misbehaving install's switch is in a cabinet inside a building. There's no water anywhere near it. And it's located in rural Vermont, which I don't think is a high EMI environment. Not near power lines or anything either.

If the cable is going to be run outdoors, then definitely get one rated for outdoor use (or run in a conduit). UV and weathering will rapidly cause deterioation of standard ethernet cable and the plastic will start cracking. These small cracks plus a bit of moisture in the air will start causing weird and unpredictable issues.

I know when running ethernet cables between buildings you have to be careful not to create 'ground loops'. That is, if you have a camera powered by a supply in one building, and then run a shielded cable to a switch in another building, you risk joining the earths of the two buildings together. I think in these cases unshielded is better.

Yes, I know. My question is whether I should use shielded cable for devices mounted to the outside of the building. The cable won�t be exposed to the outside.

If there is possible interference present (although in the location described that does not sound likely), then shielded yes. But max length is 100M. I suspect that approaching that length will be an issue also. I also am working in the assumption this CAT6 cable for those speeds?

Under an eve and reasonably weather-protected? Regular Cat 5/6 cable will do the job. Up on the peak of a roof or on a tower? Shielded is a good idea. The only shielded I'm using is on a radio tower with other uses.

Ubiquiti AirMax stuff by chance? They're well-known for doing this. Ubiquiti's "solution" of using shielded cable doesn't make a difference. A friend of mine has a Wireless ISP and we've tried multiple combinations. All of the older Ubiquiti stuff will eventually exhibit this problem. He's made his own home-build surge protectors which HAVE made a difference. But honestly, on top of my office building I'm using a Nanobeam M5 with regular white indoor Cat5E cable with one of his surge protectors. It's made it through numerous hurricanes and the Florida sun. Still connecting at full speed. This Nanobeam replaced an original Nanobeam which would drop down to 10Mbps and stay there until it was rebooted.

It's regular Unifi, actually - the AP-AC Mesh. Maybe it suffers from the same issue.

I already bought the shielded cable. At worst, it's just a little extra work to terminate it.

There was exterior extreme weather shielded cable before I retired and sold my wiring service.
Absolutely waterproof and -50C to 150C
Not cheap but the only type that was offered to customers with outdoors work that we feel comfortable offering any warranty.

Neat, yeah, the install I'm doing won't have the cable exposed (it'll go straight from the junction box to the back of the camera).

I've done lots of PoE camera runs for myself, family and friends. For runs <200 ft, I wouldn't waste your time or money with shielded cables. The shielding is to avoid RFI or EMI. That's really only needed for speeds >1Gbps or longer runs. PoE cams only use a few Mbps of bandwidth each. For runs from my core switch to all the general jacks/devices in our house I usually just go with Cat 5e because it's cheap. For intra switch, intra rack, or AP to core runs, I use Cat 6 or SFP+.

If it's under the eaves, you'll prob not have to worry too much about weatherproofing it, but I'd still recommend using the waterproof Ethernet connector thingy if your camera(s) come with them. I skipped it on an install, and after a few years the RJ-45 pins went bad and I had to re-crimp a new connector. This time I used the waterproof connectors and I've never had another issue. I don't think it directly got wet, but it's humid where I live so that might have contributed.

This is why I would terminate the cable in an attic and then use a regular patch cable to go from there to the device. This way, you can just swap the cable if you ever need to without replacing the entire run.

I haven't had an issue with the ports on those and I have a small amount (10) at my office. The arena near here has a boatload of them and while they have issues, the APs have behaved.