POE Lighting

[wwhitney]

By the way, take a look at 725.144. It makes clear that POE is covered by article 725.

It (2017) also requires copper conductors (no CCA), and it explains the -LP rating the cvillej17 mentioned. It's the ampacity of the conductors in the cable.
And the informational note says the -LP rating reflects being in an arbitrarily large bundle; higher ratings apply in smaller bundles.

Cvillej17's recommendation of having a rating of at least -LP(0.6A) corresponds with the current per conductor being 480 ma max rather than 960 ma. Not sure why -LP(0.5A) wouldn't be sufficient.

Cheers, Wayne

 

[Amps]

I read an article on PoE that had to do with the RJ45 connectors being used. Lots of arching issues and fires due to poor crimping and low grade connectors.

 

[petersonra]

I read an article on PoE that had to do with the RJ45 connectors being used. Lots of arching issues and fires due to poor crimping and low grade connectors.

There are a lot of electricians who firmly believe that they can make up a better connection in the field with a pair of pliers and whatever connectors they might happen to have than a machine can make in a factory and refuse to buy pre-terminated cables.

 

[hbiss]

I read an article on PoE that had to do with the RJ45 connectors being used. Lots of arching issues and fires due to poor crimping and low grade connectors.

I never thought about that aspect. Even if the conductors themselves are sufficient to handle the current, the "RJ-45" was never meant to handle current to begin with.

There are a lot of electricians who firmly believe that they can make up a better connection in the field with a pair of pliers and whatever connectors they might happen to have...

I've always been against the field installation of connectors but when you add power handling it can only be a disaster.

-Hal

 

[Todd0x1]

Installed properly with the correct tooling, field applied RJ45s are every bit as good as factory applied. Biggest problem outside of just plain doing it wrong, is people using RJ45s for stranded wire on solid wire and vice versa. There are different types and it is imperative to use the right one. Here's a picture of a properly installed field RJ45. I should get a magnified closeup of the side showing the 3 pronged contact engaging the solid wire.

 

[petersonra]

Installed properly with the correct tooling, field applied RJ45s are every bit as good as factory applied. Biggest problem outside of just plain doing it wrong, is people using RJ45s for stranded wire on solid wire and vice versa. There are different types and it is imperative to use the right one. Here's a picture of a properly installed field RJ45. I should get a magnified closeup of the side showing the 3 pronged contact engaging the solid wire.

How do you know this? Just believing it is true does not make it so. Factory cables are also factory tested at the time they are made with some pretty sophisticated equipment. I don't see too many electricians with anything other than testers that only check for continuity and pin out, if they even have that.

 

[Todd0x1]

How do you know this? Just believing it is true does not make it so. Factory cables are also factory tested at the time they are made with some pretty sophisticated equipment. I don't see too many electricians with anything other than testers that only check for continuity and pin out, if they even have that.

thanks for bringing that up, I should have said' installed properly with the correct tooling and tested with a cable certifier,'

 

[Amps]

Factory cables have their place but if you have to fish cables in walls, etc. the RJ45s can get beat up. Sometimes making them in the field is the only way especially for custom lengths.
Another thing I came across when almost buying a bundled IP camera kit was the type of factory cables that they supplied in the kit. They were cat5 CCA. Copper Coated Aluminum. I let them know that it was not a good idea to use that type of cable with PoE IP cameras and NVRs. So they added a note on their website about it. Did I get any sort of perk? No.

 

[Todd0x1]

Isn't there a distance limit for stranded wire in the ethernet spec?

 

[electrofelon]

How do you know this? Just believing it is true does not make it so. Factory cables are also factory tested at the time they are made with some pretty sophisticated equipment. I don't see too many electricians with anything other than testers that only check for continuity and pin out, if they even have that.

Chinese (who probably make 97% of these) reliability and quality control is questionable however

 

[Amps]

100 meter distance limitation for Ethernet. (330ft).

 

[hbiss]

Factory cables are also factory tested at the time they are made with some pretty sophisticated equipment.

True but factory cables are tested for ethernet use NOT power handling.

-Hal

 

[hbiss]

Isn't there a distance limit for stranded wire in the ethernet spec?

Stranded should NEVER be used as building wire. It's use is strictly for the manufacture of patch cables.

-Hal

 

[Todd0x1]

100 meter distance limitation for Ethernet. (330ft).

Right, but of that 100 meters I think only a portion of it can be stranded.

 

[Todd0x1]

Stranded should NEVER be used as building wire. It's use is strictly for the manufacture of patch cables.

-Hal

my point. which precludes factory made patch cables run to devices.

 

[GoldDigger]

Isn't there a distance limit for stranded wire in the ethernet spec?

I do not see offhand why length would be different for stranded vs. solid. Unless stretching could cause an impedance problem.

 

[hbiss]

I do not see offhand why length would be different for stranded vs. solid.

As far as I know there is no difference.

You don't want to use stranded for building wire mainly because you can't use it with insulation displacement terminations like patch panels. It's also very confusing if field connectors are installed because most likely the installer will only have solid wire connectors.

-Hal

 

[Todd0x1]

I do not see offhand why length would be different for stranded vs. solid. Unless stretching could cause an impedance problem.

I found it. Its buried in tia 568. 90M solid wire and 10M stranded for 100M total. The issue with stranded wire is insertion loss and how it behaves with the high frequencies ethernet operates at.

 

[Flicker Index]

Rock86,
Like any control system, there can be a lot to discuss, but to start, check out Platformatics.com. It is one of the lighting controls manufacturers in the PoE lighting space. They have an infographic on their website that might help you understand their system.
Igor, another manufacturer, is the market-share leader with systems all over the US and in 30 countries, globally. They have case studies on their site that show how PoE lighting can be implemented. Their website is igor-tech.com.

As in any PoE system, AC is converted to DC at the network switch. There are no AC drivers PoE fixtures. Instead, the LED arrays inside the fixtures are powered directly by a DC driver (node). In general, each network switchport provides up to 71 watts of power to a node. That node can power up to 4 fixtures, depending on the system and the power requirements of each fixture. Since an LED is a constant-current electronic device, the node is custom-tuned to match the mA draw of the LED array in the fixture(s). Local controls like sensors and wall switches also connect to the nodes and use the network cable for communication to control the system.
For Platformatics, each driver requires a homerun to a network switch. Igor's system allows network-daisy-chained nodes to power multiple fixtures, but there is still a power limit on each homerun.
In both systems, the node's homerun is connected to a network switch, which is connected to a central server. The server is used for system commissioning, monitoring, and occasional maintenance. The system scales like any network; more lights=more nodes=more switches.

For an open office area, multiple nodes would be necessary to power a room's worth of fixtures. HE Williams is a manufacturer that specifically sells PoE-ready lighting. They list nearly 1000 different SKUs, but because all their fixtures are LED, they can convert nearly any fixture they offer to a PoE-ready fixture. To accomplish this, they simply remove the AC driver. HE Williams owns Platformatics, so there's an obvious incentive there to offer PoE fixtures, but they also work with Igor and others. As long as the AC driver can be removed, nearly any LED fixture can be converted to PoE and dozens of manufacturers have done it.

I hope that's a good baseline without being overwhelming, but I can go into more details. Let me know when you'd like more info. As long as it might be beneficial for others here, I'm happy to post about it on this thread.

It's not a matter of simply "remove the AC driver". LED array configuration is dependent on the ballast. Both the ballast topology and LED array layout are often strongly dependent on the intended AC nominal voltage. Some LED lamps use nothing more than a series transistor or MOSFET used as a electronically controlled rheostat. Those intended for 120v nominal may have ten three-chip LED elements in series so that the string length is 30 in series (Vf of 80-90v) and two of those connected in parallel and the current is simply maintained by rapidly changing the rheostat's resistance. If the string length is maintained such that the voltage drop across the rheostat is 10% of the string voltage, then the ballasting efficiency is 90%. 230v version of this may have one string of 60 in series.

An LED lamp/luminaire that is designed with a 120-277v input using a booster PFC front-end LED ballast may operate at a voltage as high as 400v with as much as 141 chips in series (47 three chip LED elements in series on a mass produced PCB). The LED bearing PCBs are of course, mass produced. So to make this work, they'd have to use different LED PCBs requiring the optical end of the lamp/luminaire to be assembled separately or have the AC ballast replaced with a DC input LED ballast with transformation ratio in excess of 8 (50v input to 400v output) which will cost efficiency). It would have to be built with a different integrated LED ballast and/or different LED PCB.

 

[cvillej17]

It's not a matter of simply "remove the AC driver". LED array configuration is dependent on the ballast. Both the ballast topology and LED array layout are often strongly dependent on the intended AC nominal voltage. Some LED lamps use nothing more than a series transistor or MOSFET used as a electronically controlled rheostat. Those intended for 120v nominal may have ten three-chip LED elements in series so that the string length is 30 in series (Vf of 80-90v) and two of those connected in parallel and the current is simply maintained by rapidly changing the rheostat's resistance. If the string length is maintained such that the voltage drop across the rheostat is 10% of the string voltage, then the ballasting efficiency is 90%. 230v version of this may have one string of 60 in series.

An LED lamp/luminaire that is designed with a 120-277v input using a booster PFC front-end LED ballast may operate at a voltage as high as 400v with as much as 141 chips in series (47 three chip LED elements in series on a mass produced PCB). The LED bearing PCBs are of course, mass produced. So to make this work, they'd have to use different LED PCBs requiring the optical end of the lamp/luminaire to be assembled separately or have the AC ballast replaced with a DC input LED ballast with transformation ratio in excess of 8 (50v input to 400v output) which will cost efficiency). It would have to be built with a different integrated LED ballast and/or different LED PCB.

You are correct - some fixtures come with integrated drivers, so "simply remove the AC driver" was an oversimplification and technically incorrect. I don't know enough about each LED fixture manufacturer's build process to say how they integrate their components. The concept for a PoE fixture in general, though, is to build a PoE LED fixture that does not have a driver, but instead only an LED array, which is what HE Williams and others do with their production AC fixtures.