Cat5 wiring and lightning protection

Discussion in 'Chit-Chat' started by cam235, Apr 16, 2018.

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  1. cam235

    cam235 Pulling my weight

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    As a rare thunderstorm rolls through here, I'm just wondering- how long a run of Cat5 cable do you put in before starting to think about surge protection? Or does that even do any good? For example I have about 40' running at ground level to a camera near the front fence for a license plate cam. Now I'm sure nothing would withstand a direct hit, but is the normal ethernet magnetic isolation good enough for somewhat-nearby strikes?
     
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  2. looney2ns

    looney2ns Known around here

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    You will get a variety of opinions, but Shielded twisted pair, with a surge protector where the cable enters the house, can help mitigate damage. Of course, the shield must be properly grounded to be effective.
    https://www.amazon.com/Ubiquiti-Net...8694&sr=8-1&keywords=ubiquiti+surge+protector
     
  3. TonyR

    TonyR Known around here

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    +1 to what @looney2ns said.

    Nothing on this earth can protect from a direct hit, but having the following can help in a nearby strike. The best insurance is to unplug everything but we all know that is not going to happen every time.

    I'll go so far as to say you should install one of those ETH-SP's he suggested ANYTIME you have CAT-5e or 6 outdoors, use STP (shielded twisted pair) between the outdoor device and the ETH-SP. Use shielded RJ-45's, tie both of them (each end) to the shield and/or drain wire. From the ETH-SP to the LAN inside the house do NOT use STP.

    At the side of the house where the ETH-SP protector is mounted, if at all possible sink a 4 ft. galvanized ground rod (a 6 ft. copper-clad steel rod is better) within 12" to 18" from the ETH-SP, tie the ETH-SP grounding tab to that rod with #10 copper, dressed as straight as it can be (no sharp bends) from the rod's clamp to the ETH-SP.

    Avoid if at all possible tying into utility co.'s ground buss and having that ground wire from ETH-SP to ground rod over 2 foot in length.
     
  4. spork

    spork Young grasshopper

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    All cables entering the house are required by code to be bonded to a single point ground. Adding extra ground rods makes the problem worse if not bonded properly. If everything isn't at the same potential you are giving lightning another path causing more damage.

    I would guess the way most people install their cams is against code. I'm no expert but the only legal way is to probably use the service entrance for every cable.
     
  5. TonyR

    TonyR Known around here

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    You have no idea what you are talking about. Additionally, the terms 'grounding' and 'bonding' are not interchangeable...further evidence that you're out of your league.

    Now you are just spouting nonsense.

    These are low voltage cables and aren't require to have their shield grounded by code anyway so 'the Code' you are referring to is not applicable here. These conductors sure won't be joining 120/240 volt, split-phase electrical service wiring in proximity OR their ground point. You go ahead and do yours like that if it suits you.

    'Nuf said.
     
  6. cam235

    cam235 Pulling my weight

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    I can see where a single ground makes sense but is 12V yard lighting etc. done that way too? I wonder about holiday light strings in the yard (which generally don't even have a separate ground wire)?

    I guess a water pipe is not a cable but when I had the main electrical panel updated last year, they told me to pass city inspection they also had to have two (2) separate ground rods located near the water pipe entrance in front, so that is what they installed. Meanwhile the electrical panel and its separate grounding rod is in back.

    I guess I should qualify, "nothing I'm likely to afford/ want to do" re: direct strikes, because at least for commercial radio sites, supposedly it is possible:

    "The protection from lightning of radio communication sites can be achieved and protection from even direct lightning strikes is possible. The author is familiar with many examples where direct strikes have occurred and full protection has been achieved." -from http://www.novaris.com.au/images/stories/Sales Kit/SK09/Radio Comms.pdf

    [​IMG]
    image from Commercial Lightning Protection System Design - Lightning-protection-institute.com
     
    Last edited: Apr 16, 2018
  7. spork

    spork Young grasshopper

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    So I guess my question is where in the code does it state that low voltage cables can enter from outside without being grounded? I would like a definitive answer myself on if its actually legal. Just trying to learn here...

    cable and satellite companies I think are required to use the service entrance as well?

    I do know that adding extra ground rods to stuff that is in anyway connected to the electrical in your house can cause a lot more damage if they aren't bonded. This was written for antenna systems but shows how adding extra grounds causes more trouble.

    Station Ground

    I would be somewhat concerned about having a run of cable laying on the ground for some distance without a correct path for lightning.
     
  8. aristobrat

    aristobrat Known around here

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    Where I live, code seems to very city by city. Where are you located?
     
  9. aristobrat

    aristobrat Known around here

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    Do you use that (and the UniFi device) for cameras mounted in your soffits?
     
  10. TonyR

    TonyR Known around here

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    Dang..."you can lead a horse to water, but....."

    That's EXACTLY what the shield on the STP is for in post # 4 above. It is plugged into a function-specific surge protector which has its own driven ground rod to assist, not guarantee, in diverting static and EMI that was impressed onto the CAT cable from a nearby lightning strike or high-energy lightning event that would otherwise find its path to ground by using the data & POE pairs instead and toasting the device on the other end (IP cam, 5 GHz radio, etc.).

    Some folks are using some terms interchangeably and incorrectly and misunderstanding their purpose and function; "grounded conductor" and "grounding conductor" are not the same thing. They also do not share the same purpose as the "Neutral conductor" in an AC power supply or the "DC-" or "return" in a DC power supply. Granted, in a perfect world the white-insulated neutral conductor (the return for an AC device) and the green-insulated or bare copper earth ground conductor (protective ground for an AC device) are at the same potential but the ONLY place they are physically (and legally) tied together are in the service panel. On the other side of the house that same green or bare earth ground wire coming from the panel can be as much as 5 Ohms resistance to the ground as measured on that rod driven for the ETH-SP surge protector to tie to the shield on the STP entering the house. Why would I NOT want the lightning to be attracted to my STP's shield instead of sending it into my house? Eh?
     
    Last edited: Apr 16, 2018
  11. Mr_D

    Mr_D Pulling my weight

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    Mine enters the attic through a soffit vent, after passing through a grounding bock under the eves which is connected to a water pipe.
     
  12. TonyR

    TonyR Known around here

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    Excerpt below from EC Magazine's "Codes & Standards, Know the Rules":

    "The NEC also indicates that are some low voltage systems that are not permitted to be grounded. Those rules are found in Section 250.22(4) and (5). Section 250.22(4) provides a reference to 411.5, dealing with low voltage lighting systems. The secondary circuits supplied by transformers for these lighting systems are not permitted to be grounded. Examples of these systems include low voltage landscape lighting systems...."

    "Summary

    Low voltage systems are either grounded or ungrounded. When a low voltage system is grounded, one conductor of the system is intentionally connected to ground (earth). Equipment supplied by electrical systems of any voltage is generally required to be grounded unless the supply system operates at less than 50 volts, or where equipment is supplied by a low voltage system that is grounded in accordance with 250.112(I)."
     
  13. spork

    spork Young grasshopper

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    my concern was lightning / surge currents finding a lower resistance path through your house wiring and electronics to another ground rod. All I was trying to say is that lightning can come from the other way and end up damaging more stuff.

    thanks for the nec codes.
     
  14. TonyR

    TonyR Known around here

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    Then the rod closest to the entrance is not doing it's job? Possibly. But after living in GA and AL for half of my 69 years, I can say for certain that "lightning is gonna do whatever it wants to do and will ruin whatever it wants to".

    We get lightning here that just the sonic percussion alone will knock pictures off the wall. I've seen it come in through power lines, phone/DSL lines (the most common) and satellite coax lines. After you've put that 65" 4K UHD 3D TV on a $150 UPS, better unplug the power and the HDMI cable coming in from the satellite DVR because I've seen it go thru all that like it was a straight wire...glad I had a $250 / 5 year Geek Squad Protection Plan on a $2,500 TV in 2016. They replaced the 2 year old TV, refunded the difference in price between the old TV and the new and gave me a new 5 year plan....all at no additional cost as an apology for 3 failed attempts in 12 weeks to fix the TV on my premises.

    My point? All the preparation, surge protectors, UPSes are not an absolute guarantee, because in AL, FL, GA, MS, LA, TN & SC it's not a question of IF something is going to get fried...it's WHEN will it get fried. :facepalm:

    You're welcome.
     
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  15. looney2ns

    looney2ns Known around here

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    You can include, In, Il, Ky.

    And to clarify, we are talking about induced surges, not direct strikes. Induced, can occur from strikes up to 2 miles away. Big difference.
    A famous poster here, who is a network engineer, once said it simply "Ground Everything".
     
  16. looney2ns

    looney2ns Known around here

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    In my case, the surge protectors are in the garage, just prior to the switch. Along with shielded cat from cam to surge.
     
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  17. TonyR

    TonyR Known around here

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    Noted, Thx!

    Yep. And a direct hit.....say 'Bye Bye"!
     
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  18. spork

    spork Young grasshopper

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    here is a thread on cctvforum

    Lightning Protection - CCTV Forum

    This gentleman has installed cams that have taken direct hits. Also there are amateur radio operators that take direct hits on their antennas almost every storm that have never lost a modem etc. Whenever you read how its done the answer is always the same which is bonding all the grounds together. What I meant by another ground rod causing problems is that by being there it could prevent your primary ground from doing its job during a strike. I should have saved some of the threads I came across where amateur operators have had their stuff fried from creating a separate station ground.

    I'm not here to insult or question anyones knowledge as this is a very helpful forum but to do your own research and learn from those that take regular hits on their gear.
     
  19. nbstl68

    nbstl68 Pulling my weight

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    My place took a hit to the garage or very nearby last May. It blew out lights, sockets, sprinkler controller blown off the wall. I have up to 150 ft runs of cheap-o CAT5 ( reused from a prev returned Costco Q-See crap camera kit before I knew better) on some of the camera runs; quality shielded CAT6 on others. A Cyberpower UPS on the POE switch connecting them.
    No damage to any of the cameras occurred.

    A few clips of the strike.
    Lightning
     
  20. xtropodx

    xtropodx Young grasshopper

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    So, regardless of CatX cable, whether shielded or not, not having it grounded vs having it grounded will make little difference then in instances of direct hit ?

    Why would you bother grounding CatX cable then ?

    If everything is turned off & unplugged during a lightning storm, & cable is not grounded (or properly), can cables & PoE devices still be damaged if lightning hits down the road or nearby?
     
  21. TonyR

    TonyR Known around here

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    Because direct hits are less likely to occur and not every nearby strike causes so much ESD (Electro Static Discharge) as to cause catastrophic equipment damage when shielded and properly grounded.

    And the only way you can know if having it in place helped you is to remove it and wait....and wait....it's a lot like testing hand grenades so you know all of them are good ones and will work when needed...get my drift? :cool:
     
    Last edited: Apr 17, 2018
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  22. TonyR

    TonyR Known around here

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    Very unlikely but anything outdoors, unplugged or not, grounded or not, is fair game depending on how strong the nearby hit is. Down the road? ....you're likely OK.
     
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  23. spork

    spork Young grasshopper

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    I found another article that may be of interest. Its highly detailed about surge damages to ethernet ports.

    Designing Ethernet Cable Ports to Withstand Lightning Surges

    a clip from the section on gpr

    "Ground Potential Rise
    When lightning strikes the ground, currents up to 100 kA flow through the soil toward the center of the earth. However, since the soil has a finite resistance, the lightning current IL spreads out in many directions, represented by IL1, IL2, and IL3 in Figure 4. This creates a voltage gradient that can be represented as a set of equipotential half-spheres, indicated by the blue lines in Figure 4.

    If there are two devices nearby that each have a separate reference to ground, the surge current IL1 flowing through the soil creates a momentary difference VDIFF in the potential at the two separate ground points GND1 and GND2. This voltage difference can be several thousand volts if the lightning strike is nearby. Reference [1] contains a more detailed description of the mechanisms that lead to GPR.
    Figure 4 shows a mechanism called ground potential rise (GPR). GPR is perhaps the most complicated mechanism to explain, but it is often the root cause of surge failures on communication cables."

    Also if you read further in the comments there are others that suspect issues from having different ground references.
     
  24. xtropodx

    xtropodx Young grasshopper

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    So if you're using Cat6A S/FTP cable along with Cat6A shielded jacks, given that this would all be shielded anyway & reduce interference, why would you bother grounding this cable/jack setup if nearby/direct hit would cause damage regardless? I get it's for venting any interference that the line gathers but still, if it's already better to begin with why bother.
     
  25. TonyR

    TonyR Known around here

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    For God's sake, man! I don't know how else to re-state... "And the only way you can know if having it in place helped you is to remove it and wait....and wait....it's a lot like testing hand grenades so you know all of them are good ones and will work when needed" as above in post #21 to your virtually identical question!

    I'm begging you...PLEASE...do NOT use any kind of STP or shielded jacks and PLEASE don't ground anything, OK? Please do NOT spend an extra $100 in an effort to ASSIST in safeguarding $1K-3K worth of equipment. You are the kind of person that will ask and ask for advice and when that advice is given you'll argue the horns off a billy goat asking why you should take that advice. DISCLAIMER: I am not responsible for possible ESD damage or your neighbor running off with her son's little league coach.

    BTW, shielding of any kind does little good if not properly grounded; the EMI, RFI or ESD will likely NOT be directed away from the data-carrying conductors, the POE conductors or the equipment if the ground is NOT in place. WARNING - another simple analogy: It's like the lottery; if you play there's no guarantee you will win, but if you do NOT play, you are guaranteed NOT to win.

    Am I right? What do you think? (It's a rhetorical question).:facepalm:
     
    Last edited: Apr 20, 2018
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  26. Tinman

    Tinman Pulling my weight

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    Also remember all these grounding codes are to protect YOU as well as your equipment. The last thing you want is lightning entering your home. So it is money well spent, insurance can replace everything but YOU :)
     
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