Power over Ethernet and the National Electrical Code
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- Опубликовано: 1 июл 2024
- This video focuses on the NEC requirements for twisted pair cables used in a Power over Ethernet application. This technology is already taking a share of the commercial lighting market, and most experts agree that it is not going anywhere soon.
www.ryanjacksonelectrical.com
Great summary. I own a UL508A panel shop. We love Class II circuits. Our favorite flavor are 24VDC with a 4A 1077 circuit breaker. According to UL508A, all devices on these "limited energy circuits" are not to be investigated by UL. Allows us a lot of freedom to buy unlisted components and install them in our control panels.
I’ve been electrician for many years. I was like you, I didn’t really care about anything over 480 and certainly didn’t care about low voltage. I started doing fire, cctv access etc about a dozen years ago and I love it. I get to do lots of control work. Relays and timers etc. I find it much more interesting than the typical commercial electrical work.
I see the Axis thumbnail mid span. Axis = cost a lot and fails a lot but when it’s working it’s great.
Edit: I hate the sloppy work that is the standard of the low voltage world.
The biggest issue I foresee is some fellow electricians exceeding the distance for PoE of 100 meters that’s the standard of distance in the various IEEE 802.3 (af,at,bt type 3 and bt type 4) . It happens with DATA all the time let alone PoE but it will happen for PoE I’m sure of that.
Also Generally I agree with Ryan on everything except how he dismissed the note 2 out of hand due to connector limitations. That note is relevant if you use a better connector (Phoenix contact makes connectors rated for 1.75a) and if you understand those standards IEEE 802.3af, IEEE 802.3at use only four conductors for power. The IEEE 802.3bt type 3 can use 4 or 8 and IEEE 802.3bt type 4 uses 8. This might save some headache using the note 2 on peoples install regarding bundling BUT I think why he dismissed it out of hand like that is changes post install from 4c run install changing to 8c when bundled for 4c and that not getting changed since all the PoE stuff is basically plug and play by anyone.
The standard is 90m max length for the structured install. The 100 is overall wire length allowed before signal loss. You have to leave length for the cabinet and desktop connections.
worried about electrical safety of poe when usb is pushing 300 watts over a 40 gauge chineesium aluminum "wire", plugged into a death trap non-isolated usb charger.
Great video Ryan as always
Ryan is back
Ryan. Awesome presentation
Really enjoyed it. Keep up the great work
I would love to hear more about this subject if there have been any updates. Thank you for sharing this information, Ryan!
copper clad aluminum twisted pairs ethernet cable is all over Amazon and are fairly cheap.
hard to tell if cable is 100% copper unless cut into it.
cannot tell the type of metal by weight, unless the gauge of the twisted pair is advertised and true.
and then, there is also the problem of solid vs stranded twisted pairs.
this area definitely need more standardization.
agreed. thanks for pointing out the cheaper amazon cables. I didn't know that.
Glad you’re back!
Awesome video, thanks again Ryan and do you know if PoE lighting is also going to be installed in dwelling units or just commercial ?
@@rafaelvelasco6357 I think it will mainly be residential, at least for awhile.
@@rafaelvelasco6357 I've yet to see PoE lighting in residential. But, I'm sure it will be. With commercial, it's literally a drop-in replacement -- they fit into the standard 2'x2' ceiling grid.
@@RyanJacksonElectrical I think industrial will be the first to uptake, I'd be pushing for it in any building. No electrician needed, immediately ties into automation via cisco which I already know.
I just finish a airport job that lighting was controlled with Cat 5E. the dimmers ,switches, occupancy sensors power/ dimmer power pack was Daisy chain with cat5E. Acuity n light system within a fresco controller.
Its crazy to me that people like that can still exist but the more I think about it I'm not surprised. I've come across electrical distribution houses that don't stock ANY wire smaller than 14 AWG, even besides all the crusty electricians I've had to deal with who refuse to strip a wire with anything other than their Kliens. Even when they are faced with 400 connections in front of them that just happens to be sitting beside a box of auto strippers.
Thank you for the pointers !
Wow great message for apprentices..
As far as inspections go, how does the inspector know an ethernet cable is using POE. And even still how many conductors in the ethernet cable are being used for current. In a residential environment I could potentially have ethernet cables going from "no where" to "no where" if the equipment, (switch, camera, access point) is not installed before the electric inspection. I dont use POE injectors, I just use POE switches. As far as data with power, how does the NEC define data?
When you said 8P8C connectors are rated for 1A, is that per pin or for the entire connector? Presumably per pin like the cable ampacities? (so a 4-pair PoE injector could supply up to 4A on an 8P8C connector?) Otherwise the PoE injector you show at 15:00 would be noncompliant since it's rated for 23W@21V per port.
I found one source saying they are typically rated for 1.3A, not 1.0A, but it didn't mention per wire or total. However, the minimum rating to meet IEC 60603-7 is 1.0A per contact, so that's the way the standard is written. It has to be per contact, as both the power and return have the same current. But, when two conductor pairs are used for power, there may be an imbalance between the pairs. That's likely driven by the different twist rate to minimize crosstalk between pairs for data transmission yielding one path being longer than the other causing resistance differences. That difference is limited to 20% by IEEE PoE standards, but not all 8P8C are necessarily PoE. I've seen it used for RS-232 back in the day when that was popular.
15:23 Stock only the tiniest cable ties and you won’t need to worry about more than 7 cables per bundle.
NEVER EVER use cable ties made in lack of quality control lying cheating china. We had several china brands in work and all wete junk. At least 25% of them nroke while installing. A lot would break if you just moved tied bundle. Can't wait until computer geeks are installing luminares and PoE cables in drop ceilings.
As a computer need who dealt with IBM Bus and Tag cables (conduct or as big as my pinky) I have always had my doubts about UTP. I did run UTP in my house because I like WiFi less. Just like power wiring, termination of UTP is very dependent on the quality of work done. My prediction is that if POE becomes widespread, that amateurs will make connections that are unsafe.
While POE was designed for data network devices, using POE for lighting will inevitably lead to a race to the bottom in quality as manufacturers try to get price advantage. The place I see the biggest problems is cheap transformers as the POE source. Where will these transformers be located and when they fail will they cause fires?
It certainly looks like POE lighting will dominate within a decade. No more line voltage drivers.
still gotta get that power from someplace. just instead of ballast drivers you have poe injectors. the driver still exists, it's inside the light. so you're converting from 120 volts to 48 volts then to whatever voltage the light is running at, which is actually current regulated. we can add a lot more complication to that. lets have it call home to the "cloud" and automatic updates that reboot every light at a time you can't control and have your password stolen so some 10 year old kid can play with your lights from across the country. one day, 10 years from now the company running the servers in the "cloud" will close their doors and all your lights stop working. I'm not happy damn it :-)
Good points
Now they are led drop ceiling light powered by POE. Crazy
New USBC protocol 270 w.... I'm going to install low voltage DC receptacles in my home. Looking forward to Future flat screen TVs powered by USBC. Looking for installing solar panels with no need for an inverter exclusively to run all DC electronics and lighting... And POe cameras
I have a question at 13:30 and 13:51: Ryan, you seem to be saying the connector limits the current of the entire cable to 1 amp, and your graphic's text says the same. Is this a mistake or just me misunderstanding? When I read informational note 2 at NEC 725.144, it specifies this is "per contact" not per connector. The table is for each conductor within the cable so I want to understand this means the connector limits the entire 8 conductor cable to 8.0 amps, not to 1.0.
Great point David, I think you're right.
ive been memorizeing config b rj45 pass trough conector for cat5e or cat6 ethernet cable so i can run camera cables poe white orange, orange, white green, blue, white blue, green, white brown, brown
I was hired once at a company that installs and maintains wifi networks. the guy training me asked if I knew the order of the colors. easy, I know it better than the alphabet. but instead of saying white I say striped, that's just how I remember it. somehow he claimed I was wrong, even though I said the exact same thing in a way that makes better sense to me.
Great teaching Ryan. All of us have to get familiar with POE (Technology). Just one question, even if the cable is - LP, the terminations still will be 1 amp? the only thing is that we can bundle them without derating right?
Yes, exactly right.
@@RyanJacksonElectrical Thanks a lot. Blessings. for you and your work
This dinosaur thanks you, we must be prepared for when this POE...Comet Hits.
How is "bundle" defined for ladder tray? I could have 75 cables in a tray that is only stacked 3 wires high. No way that is the same heat build up of 75 wires in a round bundle. In the tray for the one center wire on the top you would only have 1 wire and on the bottom a bar every 12" under 1 wire. Also what about wires being bundled through a chase between floors? And that is the only instance they are bundled in high density. I see engineers spec. A couple of 4" conduits to accomplish this.
It's not defined. The ampacity adjustments are usually not a lot to worry about, however, as the power flowing through a cable is going to be limited by the source and by the load.
The world still needs dinosaurs. I'd much rather call in someone who knows their job inside and out than someone who claims to be able to do everything. The generalists tend to be mediocre at best. I've yet to find an electrician who was worth a **** at running data systems. (those are very different wires, for very different applications.)
Interesting
Nothing wrong with having cat wires against the roof. That's the whole point you can drill straight through no fire risk. Realize 192 wires is 4 48 port switches. On a typical building floor that is very common. Also they added the must be copper because if you poke around from 2008 through 2019 they were making copper clad cat 5e. If you picked up a box and though damn is that empty, it was copper clad. Data didn't care and it saved money now they added power, which is more than those wires can take.
I agree that you wouldn't start a fire drilling through the cable. My thought is that you must comply with certain portion of 300.4, why not all of it. We are either concerned about damage or we are not, no sense in only going halfway.
@@RyanJacksonElectrical kinda, the code is to protect from fire and safety. If it's stupid but safe we're not nannies, though you're right it's probably the best place to put it. My concern is you're going to start seeing people push lots of rules to try and pull PoE/Data to keep up the walled garden that has become electrical work. I look around my home and I can see in the near future only needing a single 120v outlet per room maybe. With the exception of the garage, kitchen and basement of course.
Been watching some videos on POE lighting the few I have watched does not mention anything about exit lights ?
I've never seen them, but if they don't already exist I think they will soon. With their low power consumption it seems they'd be a prime candidate.
Watched a vid maybe 6 months ago and they stated that somebody did a new office where all the luminares including the exit lights were Poe. In our area years ago if you had dual primary service you did not need a battery for exit ligjts. With LED can not believe how small the batteries are in exit ligjts.
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Yeah the electrician's will still doing lighting.... Case in point, I just saw house with over 70 canless recessed lights installed with 120 going to each one of them through a little junction box with a transformer... One for each light.... Absolute insanity... Absolute waste of copper. They could have put an inverter in the basement and ran 16 gauge in zones to each one of those lights that dropout less than 10 w each.
_"The primary concern is reducing the threat of fire..."_ Bull. They just want to poke their noise into a new business. Where's the _evidence_ of PoE cabling starting fires? (nowhere, because they don't. plus, CMR and CMP cables don't burn.) Even with 802.3bt, that's 100W delivered with 71W available at the device -- so 29W dissipated across all 8 wires, and to drop that much it'll be a pretty long run. (so less than 24mW per foot [150ft drop]) It would take some very large bundles -- with ALL of the runs providing type 3 or 4 power levels -- to even generate measurable heat. And it will never be hot enough to start a fire. Your cheap-as-sin chinesium PoE power supply, however, is much more of a fire hazard. (as is bolting the PS to the roof and then driving a screw into it from the other side.)
(translation: because a growing number of installations are switching to PoE fed LED lighting, the NFPA doesn't want to be left out. You can't escape The Code.)
The substantiation was based on a UL fact finding study. UL. 2015a. Fact Finding Report on Power over Local Area Network Type Cables (4-Pair Data /
Communications Cables) . Washington: SPI (Society of the Plastics Industry).
@@RyanJacksonElectrical Thanks! Reading the 164pg report now. First take... UL pushed 2x the power current PoE standards allow. (802.3bt [2018] is just shy of 1A *per pair* not per wire.) Also, the IT world has been using PoE for over a decade (and telco for half a century); I'd like to see the proof it's _actually_ caused fires.
@@RyanJacksonElectrical Oddly uncharacteristic testing from the UL. Having sent things through the process, I'd expect them to test with their usual "real world" conditions, not hundreds of feet of cable looped into a single-span-light-bulb-filament. And it still didn't cause a fire -- the way they tested, it stops once the now-single-wire breaks. Way to "take it to extremes"! I've never seen anyone bundle 100 cables out to 100W PD's. (cameras, APs, POS terminals, PoE powered switches, etc.) [that'd be 10KW of PSE's in the rack/closet. that's an insane amount of power, btw.] Even in the densest MDF/IDF's I've seen, the large bundles split out rather quickly.
I think what we're preparing for is more a case of power-over-cat5, and less power-over-ethernet because many of these LED lights aren't actually using the data part of the spec. Some of the higher end lights are addressable -- to control brightness, color temp, etc., but the cheap ones have no comm logic in them at all. Class 1/2/3 cabling should have similar derating and bundling constraints as other "power" wiring, _if they're being used to carry power._ This will be hard to police in communication systems as it's hard to know (a) which cables will be used for power, (b) how much power those cables will carry, and (c) where in the bundle each power carrying cable lives (a cable in the center can't carry the same load as one on the edge.) Data cabling is a highly dynamic environment.