PoE surge protection.

[luk8899]

I have a system with 10 cameras and 3 L3 managed PoE switches (cheap Tenda TEG5310P). One switch is installed in my house, it has 4 cameras connected via cables that go out of the building and are run on the edges of the roof overhang. 3 have these tiny PoE 48V to 12V adapters and one has builtin PoE. Another switch is in a detached garage(the cable connecting them is undergound). That switch has 4 cameras too. 2 on the building itself and two connected with 60m of underground cable on a 6m tall steel pole. The third switch, also attached with underground wiring, is in another building. The third switch has only 2 cameras, both attached via about 60m of underground cable and located on a 6m tall steel pole.

We've been having lots of lightning storms around here, although none of them was causing lightning within half a km. Also most of this ligtning activity was happening during the day. One night at 1:36am one of my switches PoE chip died (it still supplies power, but one can't get the temperature, also it shows no power statictics, it makes a hissing noise and the whole switch gets very hot very quick) - this is the switch at home. Also 3 cameras connected to it had their PoE adapters die. Then on switch no 2, one camera on a steel pole had its PoE adapter die (the other on the same pole - with builtuin PoE is fine). And in switch no 3 same thing. One of the cameras on the pole has a dead PoE adapter. It seems like a calssic surge, but it happened while there was no lightning storm nearby so I'm guessing, perhaps it came via the power line? No other devices were damaged at home. I have whole home surge protectors in my electric panel.

So the question is, what do I need to add in terms of surge protection to prevent this happening in future. Add ethernet surge protection? To all cables? Or just some? Get better quality PoE adapters? What do you do to prevent lightning and power surges caused by lightning destroying parts of tyour system?

 

[Teken]

I have a system with 10 cameras and 3 L3 managed PoE switches (cheap Tenda TEG5310P). One switch is installed in my house, it has 4 cameras connected via cables that go out of the building and are run on the edges of the roof overhang. 3 have these tiny PoE 48V to 12V adapters and one has builtin PoE. Another switch is in a detached garage(the cable connecting them is undergound). That switch has 4 cameras too. 2 on the building itself and two connected with 60m of underground cable on a 6m tall steel pole. The third switch, also attached with underground wiring, is in another building. The third switch has only 2 cameras, both attached via about 60m of underground cable and located on a 6m tall steel pole.

We've been having lots of lightning storms around here, although none of them was causing lightning within half a km. Also most of this ligtning activity was happening during the day. One night at 1:36am one of my switches PoE chip died (it still supplies power, but one can't get the temperature, also it shows no power statictics, it makes a hissing noise and the whole switch gets very hot very quick) - this is the switch at home. Also 3 cameras connected to it had their PoE adapters die. Then on switch no 2, one camera on a steel pole had its PoE adapter die (the other on the same pole - with builtuin PoE is fine). And in switch no 3 same thing. One of the cameras on the pole has a dead PoE adapter. It seems like a calssic surge, but it happened while there was no lightning storm nearby so I'm guessing, perhaps it came via the power line? No other devices were damaged at home. I have whole home surge protectors in my electric panel.

So the question is, what do I need to add in terms of surge protection to prevent this happening in future. Add ethernet surge protection? To all cables? Or just some? Get better quality PoE adapters? What do you do to prevent lightning and power surges caused by lightning destroying parts of tyour system?

The solution isn’t just the installation and use of a certified UL / cUL IEEE SPD (Surge Protection Device). Lightning / surge protection is a System.

In simple terms a low resistance Earth ground. Proper shielding and isolation. SPD to absorb and shunt to ground excess voltage / current.

If you want to know more ask here or search on this forum about SPD, Surge Protection, Grounding.

 

[luk8899]

The solution isn’t just the installation and use of a certified UL / cUL IEEE SPD (Surge Protection Device). Lightning / surge protection is a System.

In simple terms a low resistance Earth ground. Proper shielding and isolation. SPD to absorb and shunt to ground excess voltage / current.

If you want to know more ask here or search on this forum about SPD, Surge Protection, Grounding.

Thanks for answering . I have good grounding where switches are located(in all 3 buildings), but there is no grounding where cameras are. I have used foil shielded wire just in case I need it in future, but I haven't got the shields connected at camera side (the Poe adapters don't use shielded rj45 receptacles).

Can ethernet surge protection be effective if it's only on the switch side? If not and you have to have both sides, can you use the Ethernet cable shield as ground connection?

 

[Teken]

Ideally everything is shielded and connected to the single point earth grounding system in the home / business electrical system. For shielded Ethernet cable to work as expected and offer shielding and grounding both RJ45 connectors must be the shielded type.

That same cable either inserts into a switch / POE switch which is powered by grounded 120 / 220 / 230 / 240 VAC system.

If the Ethernet cable goes to a panel it too must be shielded which gets connected to a grounding bus bar to ease interconnection for all equipment like a switch, panel, UPS, NVR, NAS, Server, Rack to the single point grounding system of the home. If you only have enough finances to protect one end of the network infrastructure than it makes sense to install the SPD at the camera.

If you can only install the SPD at the switch side that’s fine too but it’s a compromise.

Shielding & Grounding is one the most important aspect of RFI / EMI protection

Isolation and decoupling is the other parts in the solution using fiber to isolate and decouple the copper wiring using a media converter. Other ways are to use PtP wireless connectivity to bridge the two sides to the home network. Extreme solutions are to use a independent solar system that powers & transmits either via fiber or PtP wireless bridge.

As it relates to physical lightning protection at a tower / poll it’s always low resistance grounding with the correct (AWG) gauge of grounding wire that bonds to an approved grounding rod. Next is a lightning rod, lightning brush, to active ion generation to dissipate positive ions from being present and thus reduces the incident of lightning being attracted at the top of the pole or tower.

In case it wasn’t made clear a camera mounted to a pole that has Ethernet cable going back to the home is ONLY grounded at the home! There are obvious conflicts because normally a pole is installed in the ground! The same metal parts of the camera are also connected to the metal pole which is somewhat grounded to earth.

This is why you see most of the cameras have plastic RJ45 connectors to decouple itself from the frame.

Regardless the purpose of shielding is to prevent the Ethernet cable from acting like a giant antenna! Any voltage potential seen on the cable is shunted to earth ground. When a SPD is in place it offers an added layer of protection where a voltage rise comes through the wiring from other entry points like a camera, switch, telco, coaxial.

 

[luk8899]

Thanks. My grounding setup is a bit complex. Initially all 3 buildings had their own grounds. Then the house and the closest building grounds were connected together with direct underground wire. So they are now one ground. Building no 3 is separately grounded. I might change this in future, but for now it has to stay that way.

The house and building no2 both have class 1+2 SPDs on utility entrances.

Switches should be good up to 6kV of surge based on the datasheet. This makes me think the switch fault is not related to the surge. I just discovered that the poe chip doesn't report the temperature nor power at the same time.

This means these Poe splitters are extremely sensitive. If the switches are well grounded and they have some surge protection built in(it doesn't say which class, only that it is, up to 6kV"). It doesn't inspire confidence any surge protection at the switch will be able to protect these adapters.

I opened one (pic below) and they have absolutely nothing in terms of surge protection. Probably just rain falling on the cable building up static electricity is enough to kill one of these. That's not good as I don't have more space where cameras are to fit surge protection in front. If anyone knows poe 48v to 12V 2a splitters with surge protection please let me know.


Edit: I've just been checking prices of PoE Ethernet SPDs for 4 and 8 ports and prices are absolutely bonkers considering these are consumable items without ability to replace individual failing SPDs. I can get Poe switches cheaper than what they want for these devices.

It seems a DIY electronic project is in order. My wish list for such SPD:

• modular (2 or 4 ports units so less than 8 have to be replaced)
• proper class 2 SPD (maybe 2+3?)
• some way to test it is still working.
• cable interface on both ends so doesn't waste rj45 plugs.

 

[Teken]

Thanks. My grounding setup is a bit complex. Initially all 3 buildings had their own grounds. Then the house and the closest building grounds were connected together with direct underground wire. So they are now one ground. Building no 3 is separately grounded. I might change this in future, but for now it has to stay that way.

The house and building no2 both have class 1+2 SPDs on utility entrances.

Switches should be good up to 6kV of surge based on the datasheet. This makes me think the switch fault is not related to the surge. I just discovered that the poe chip doesn't report the temperature nor power at the same time.

This means these Poe splitters are extremely sensitive. If the switches are well grounded and they have some surge protection built in(it doesn't say which class, only that it is, up to 6kV"). It doesn't inspire confidence any surge protection at the switch will be able to protect these adapters.

I opened one (pic below) and they have absolutely nothing in terms of surge protection. Probably just rain falling on the cable building up static electricity is enough to kill one of these. That's not good as I don't have more space where cameras are to fit surge protection in front. If anyone knows poe 48v to 12V 2a splitters with surge protection please let me know.
View attachment 195779

Edit: I've just been checking prices of PoE Ethernet SPDs for 4 and 8 ports and prices are absolutely bonkers considering these are consumable items without ability to replace individual failing SPDs. I can get Poe switches cheaper than what they want for these devices.

It seems a DIY electronic project is in order. My wish list for such SPD:

• modular (2 or 4 ports units so less than 8 have to be replaced)
• proper class 2 SPD (maybe 2+3?)
• some way to test it is still working.
• cable interface on both ends so doesn't waste rj45 plugs.

If the shielded cable is already in place as you said the easiest and most productive (next steps) are to use the correct shielded RJ45 connectors on both ends.

Adding a SPD of any kind no matter the cost will NOT help prevent the wire you have now to act like a giant antenna.

The SPD will not protect the existing Ethernet wiring from (induced voltage) generated by a lightning strike.

Only a properly terminated (shielded RJ45) connectors that are properly grounded to the switch. Which is bonded to the single point earth grounding system in the home will offer that protection.

As stated earlier using fibre is also a tried and true method to isolate and decouple the copper wiring from two points. It should be noted (IF) you use armoured fibre cable it too must be properly grounded!

Lastly, it’s imperative to also understand (IF) you have a coiled service loop on either side of the installation.

You literally have a giant coiled antenna & magnet!

Besides the very long antenna you have now in place. The service loop of wire if in place is an induction coil just waiting to be energized to become a giant magnet.

This magnet once induced by lightning will generate hundreds to thousands of volts! Anyone who is involved with radio knows it doesn’t take a very long antenna to send / receive a signal from across the world.

As such what do you think dozens of meters of copper wire will do? Never mind a coiled service loop of Ethernet cable that isn’t properly shielded and terminated to a single point ground?

 

[luk8899]

I'm leaning towards the understanding that shields acting as a giant antennas picked up a nearby lightning strikes. Perhaps the shape of the cable influenced why some cables were affected and not the others.

I'll be testing grounds and redoing rj45 on the switch ends to have the shields connected today (on one side only where the ground potential is different on the remote end).

Also hopefully today I'm getting a new PoE switch so I'l lbe able to test if all 3 adapters in the house are definitely broken(but all the switch ports connected to them are so there is 99% chance they are dead too).

Does everyone, in areas with lightning, have surge protection for their outdoor PoE cameras? What do others use for surge protectioon of PoE etherne? Fiber is out of the question for me. I have to make do with copper.

 

[Teken]

I'm leaning towards the understanding that shields acting as a giant antennas picked up a nearby lightning strikes. Perhaps the shape of the cable influenced why some cables were affected and not the others.

I'll be testing grounds and redoing rj45 on the switch ends to have the shields connected today (on one side only where the ground potential is different on the remote end).

Also hopefully today I'm getting a new PoE switch so I'l lbe able to test if all 3 adapters in the house are definitely broken(but all the switch ports connected to them are so there is 99% chance they are dead too).

Does everyone, in areas with lightning, have surge protection for their outdoor PoE cameras? What do others use for surge protectioon of PoE etherne? Fiber is out of the question for me. I have to make do with copper.

The vast majority of the general public have nothing as it relates to a SPD. People by their very nature are reactionary to things that happen.

I use a combination of brands for different applications such as APC, Tripplight, Citel, Ditek, Siemens, Leviton, Pass & Seymour, etc

It’s important to have all four SPD Types in place for a layered protection. Type 1 at the service meter, Type 2 at the service panel, Type 3 at the point of use, Type 4 inline such as a POE, HVAC, etc.

Citel, Ditek, and others have been used for POE.

 

[luk8899]

The vast majority of the general public have nothing as it relates to a SPD. People by their very nature are reactionary to things that happen.

I use a combination of brands for different applications such as APC, Tripplight, Citel, Ditek, Siemens, Leviton, Pass & Seymour, etc

It’s important to have all four SPD Types in place for a layered protection. Type 1 at the service meter, Type 2 at the service panel, Type 3 at the point of use, Type 4 inline such as a POE, HVAC, etc.

Citel, Ditek, and others have been used for POE.

Thanks for sharing. I guess you're an example of someone having pretty good SPD setup.

I'd also love to hear of experiences of people with less than ideal setups. Hopefully living in places with lots of lightning and highly charged rain. To explain what I mean by highly charged rain consider that when I was a kid we run Ethernet wires between our apartment blocks - 12m above ground, 100m long roughly. Of course there was no SPDs, unshielded wire, and we just disconnected them when not in use and tied them around a radiator's pipe. I remember watching sparks over an inch long between the rj45 and the pipe, every 20s or so as the wire was rained on by a summer rain.

So I wonder, is there anyone there living in similar conditions that just gets by on shielding alone (for poe, ac power is another matter altogether).

Please note we're talking specifically about Poe (or Ethernet in general). Not so much power. Power surge protection for me is pretty straightforward. As you said. Class/Type 1+2 in the utility panel. Class 3 at devices if they need it. (I wasnt aware of Type 4) .


Now the new switch arrived, but I'm reluctant to plug it in. I'll be replacing rj45s connecting the shields when I go to fit the switch, but the dillema I now have is. Is it sufficient to connect the shields or do I need actual class 2 SPD on these Ethernet lines (on the switch end)? Assuming the answer is "yes doh", how strong of a yes is it? Is it, "yeah, better have one, but it should be fine for a bit" or "it will get killed by the first proper rain static, let alone lightning" - which is what has happened with shields disconnected on both ends. If the latter is closer to the truth I'll make my own, but it'll take a month or so. The question is, will I be replacing splitters and switches in the meantime?

Then the second thing is. I was thinking how can induced currents dissipate in various parts of my PoE system. Wiring and switches is obvious. Through whatever input protection switches have plus the shield. Cameras have DC minus bonded to their case which is either in a steel pole or a wooden structure. Then there are these poe splitters that on the long wire side connect the rj45 shield to dc-. On the camera side they use unshielded Rj45s.

So I'm thinking it is very likely what has happened so far (at least with isolated cameras on wood) the camera case has built up charge due to rain static (no evidence of nearby lightning, all cameras failing during heavy rain), this goes through dc- into the poe splitter until eventually it reaches breakdown levels sending thousands of volts over signal wires. So this explains killing all the splitters serving cameras on the house and the house switch (all isolated).

It also explains why the switches serving cameras on steel poles were not damaged. Steel poles provided enough of grounding to dissipate most of the charge, but crappy splitters got killed anyway.

Coming back to PoE SPDs.
The cheapest Ethernet/PoE surge protection I could trust (as they actually give the specifications and show internal photos) are these 4 port modules made by a local company. They cost about $100 each so $25 per port. And they use about $3 worth of parts per port. I'm planning to make my own if I have enough time.