Calvin Thomas shared some of the greatest wisdom concerning pulling Ethernet cable.. Sadly it is only us Professionals who have pulled lots of cable, throughout many different environments, whom understand the value in pulling LOTS OF SPARE runs.
So let me expand on the topic:
- I pull a minimum of 3x what I need; and,
- Always give a plentiful extra amount of slack (make cables TOO LONG, longer than you think you need)
Pulling 2x the amount of cable, would ONLY protect against a failed/failing/damaged cable, with the spare (2nd) cable acting as a replacement to the bad cable.
That said, 2x the amount of cable, does NOT provide for future needs and expansion.
Pulling 3x the amount of cable needed, barely covers both damaged cables & future expansion, and thus brings me to sharing that on client site projects I oversee, I usually pull 4x the cable.
As an example, yesterday, we finished a nightmare project in which we've been working on for almost 6 weeks, involving alot of dirt moving.. We trenched 500+ ft 2+ ft deep[with high end Ditch witch].
To my point, there was a home run that I spent about a day and began. We needed a single cable, so, I naturally pulled 4. You'd think that'd be enough, right?
Heck no! Tech's spent about two days finishing that run.. So a week or two later, after burning thru all 4 lines (with one being bad and unusable because it required PoE, had to re-pull cable (just two this time). And this was PAINFUL as a result of the cable run GOING THRU about 30-50 ZIP ties [only reachable by ladder] which supported & affixed the cables. Alot of ladder moving and climbing!
Speaking about that same run, had another cable run which went an additional 100+ ft beyond to an Outdoor AP. Ironically, when cable was pulled for that particular AP, only a single spare was pulled, so 2 home run's. Fast forward, the AP cable was BAD and HAD to be replaced. You might think, no problem, they pulled a 2nd spare cable, right?
Heck no, it wouldn't be that easy, to just use a spare cable pulled at the same time. Why not? Because there was NO MORE spare cable. THE CLIENT informs us, during the project, that he needs an Ethernet cable to [a device located along that run; which was some solar controlling equipment for a massive solar panel array at distant location of the property].
The point is that, NOT ONCE, but friggin TWICE, on the same run, we had to re-pull cable. Ya know that having to RE-DO something just once is painful enough, but f'ing twice?!?!? And that happened to THE GUY [me] whom pulls MORE SPARE CABLE THAN ANY OTHER PERSON or company!
That project was so custom, that I encountered and had to deal with I think, every possible issue that could be:
Ethernet runs far exceeding 100m/328ft (handled with Ubiquiti NanoSwitches; very inexpensive solution @ only $50/ea);
Inline PoE switches unable to handle the necessary current for all the PoE devices downstream;
Ethernet cable [following PoE standards, such as 4,5+/7,8- passive being incapable of handling downstream device current needs;
No equipment or method(s) by which to even measure, test and/or identify current draw of any particular PoE device(s) or Ethernet cable;
IP Cameras Infrared at night causing current draws that exceed switch and cable capacity causing many other Cameras and other PoE network devices to power cycle, rotating across many devices;
Personally expecting any 24vdc PoE device to power on and function properly with 12+ vdc, which has been my experience; Discovered [only after using a LAB Bench Adjustable Voltage & Current Power Supply] that some Ubiquiti outdoor equipment (AP's & Bridges) would not power on UNDER 18vdc. This issue presented as a result of voltage drops over long cable runs, where in our case, many devices were functioning and say there was 15vdc at the device ends, while some devices (those AP's & Bridges) refused to even power on.
Amcrest 4k Cameras refusing to power on... Yay.. Cameras were satellite cameras at distant locations [without home runs to PoE rack switches], and network connected via wireless Ubiquiti bridges. I had custom passively [fed] power to NanoSwitches [which powered up just fine] that passively passed thru the PoE power downstream thru all switch ports.
Not getting into all the details of the newer PoE standards, it's a headache and hassle to deal with... One of which requires the device (ie an IP Camera) to talk back and forth with the Switch, BEFORE, the switch will turn the power on and send PoE power down the Ethernet cable to the camera. In my wise logic, I assumed that if I passively injected [PoE power] [always being on] that the Cameras would power up just fine. Instead, after I identified the problem and solution, complained to my co-worker about having to custom manufacture special PoE power cables for every single dam camera. He wouldn't believe it or me and the ensuing loud verbal argument, might have led spectators to believe that it was the 4th of July.
The solution was to terminate a short patch cable in which at one end, the std passive PoE wires (4,5+/7,8- which are the Blue & Brown pairs) were not inserted into the crimped RJ45 but instead soldered [and covered with heatshrink] to a barrel power connector which plugged into each camera's power jack [beside the Ethernet jack].
- Ubiquiti passive PoE Injector 'bricks' [always putting out 24vdc] at a half amp (0.5 Amp) deceptively incapable of power multiple devices (2 to 4 PoE devices)
During this project, I encountered problems and hurdles, never before seen or thought of [by myself] over the past 25 years of doing this [work professionally and paid].
Excess cable slack having caused a very weird issue at one location with 4 devices (PoE Switch powering 3 IP Cameras). This was a 100ft+ run of expensive Direct Burial Cat6 cable inside 1" conduit buried in an appx 2ft deep trench. Despite the Switch powering on and remaining on, and despite the cameras appearing to power on and show link lights on the switch, the Cameras were not functioning and had no network communication. I'd had a large excess of cable slack (30-50ft) in which instead of cutting off, I first coiled up into a 2.5ft long bundle with large zip ties around it to keep the cable together as a bundle. I don't completely understand what was happening, but suspect the bunbled cable behaved like a wire coil and did something weird to the power and/or data running thru that cable.
After hooking up one of my custom mfr'd Inline PoE Ethernet Voltage and Amperage Current Meters, was I able to VISUALLY see the problem. The current draw was only 0.04 Amp's. This caught my attention, contrasted by all other locations drawing at least .20 to a half amp, usually was .3x or .4x Amp. Scratching my head, why this location was drawing less than a tenth of the current of any other location. Asking myself 'Whats differrent?' And I got to spend a half day, bathing in the dirt, digging up that slack, cutting it, re-terminating and then back-filling.
Years ago, there was a Texas based company/business, PoE texas or something, that made & sold PoE voltage regulator pigtails (regulated 12-48vdc down to 5 or 12vdc to power PoE devices such as IP Cameras). In my case, I needed a very specialized device, solution and piece of test equipment that to my knowledge doesn't exist commercially. I ended up ordering [at inexpensive price of about $4 ea [5 for $20] a qty of Chinese made dual display digitial DC Power & Current Meters
and proceeded to solder them up with a short piece of Ethernet cable with a keystone on the [input] end and an rj45 on the device end. I used them with any PoE device, unplugging ethernet cable from the PoE device, then plugged my inline meters rj45 end into the PoE device and the Ethernet cable into the keystone on the other end of my meter. The meter told me both the voltage going into the PoE device and the current being drawn [in Amps]. And for anyone whom wants to mfr such themselves, I chose to go self powered, meaning the meters were PoE powered to avoid the hassle of batteries.
At PoE device locations (Single poles containing a PoE powered switch with multiple Outdoor IP Cameras) in which current demands could not be met with Manufacturer PoE injector bricks, I chose to utilize [Universal] Laptop AC Adapters capable of up to 24vdc output at a couple amps;
For any longer length PoE run's, I utilized Variable Voltage 10Amp DC Power Supplies with Digital Display of the Output Voltage. We ordered these very inexpensively at $40/ea and utilized them [in the last Project} to power 7-12 PoE devices downstream. Yes, that's a $40 power supply to power a dozen PoE devices. And regardless of the length of our Ethernet cable run, we could raise or lower, the supply's output [while accounting for the voltage drop over the cable run] to precisely give us whatever voltage we desired at the cable run/devices end.
I.e. on one of our longest runs, we sent 36vdc down and had a 15vdc drop giving us about 21vdc at the PoE devices. If I wanted, could increase the power supply's output to 39vdc which would then give us 24vdc for the devices at the end of the run.
Though more costly, break out the Lab Bench Power Supplies!! Having experienced 6 different PoE power related problems, and needing more information (diagnosing things) I chose to just ordered a new 10 Amp Lab Bench Supply overnight from Amazon [was about $85]. If not permanently deployed for your PoE power needs, at least utilize one or two of these for testing & diagnosing both voltage needs & outputs, but also current draw and needs. You will be able to instantly adjust voltage and/or current levels while observing the impact on your PoE devices. Note that 10Amps is likely overkill and that 2 or 5 Amp supply's may meet your needs.
Overcoming standard PoE cable's max current limitations (translates to max number of downstream PoE devices in which can be powered by a single PoE cable. My solution was to send power down one of my SPARE Ethernet Cables, logically thinking, I chose to use the solid color wires (blue, brown, green, orange) for the Negative and all the White striped wires (Orange/White, Blue/Wh, Green/Wh, Brown/Wh) for the Positive and then Injected the power to the device(s) at the other end of the run by Splicing and soldering between the data and power ethernet cables
My key points are:
- PULL lots of extra cables on every run (a minimum of 3x your needs), as I say 'Four or more!';
- Waste the cable and ALWAYS plentifully give slack at both ends of your cable runs;
- Always run Outdoor Buried cable thru conduit! No if and or buts about it!
2021, Southern California, Home Depot, at only $4 per [10ft] section of 1" conduit, even the poor can afford it!
- If struggling with PoE, insert inline voltage and current meters at each end place;
- Utilize Lab Bench Power Supply's to light up your PoE run(s) & devices