Cat5 wiring and lightning protection

[TonyR]

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 ?

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?

 

[TonyR]

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?

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.

 

[spork]

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.

 

[xtropodx]

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.

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.

 

[TonyR]

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.

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).

 

[Tinman]

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

 

[camerafool]

I recently lost some outdoor cameras and POE switches to lightning. Fortunately I'd isolated the switches serving those cameras with a short length of fiber optic cable. Setup is cleaner if your switch has SFP port(s) as you'll only need one media converter.
https://www.amazon.com/gp/product/B004Z9301I/
https://www.amazon.com/gp/product/B004RB4LOY/
https://www.amazon.com/gp/product/B003CFATL0/

 

[aristobrat]

Fortunately I'd isolated the switches serving those cameras with a short length of fiber optic cable.

I've been meaning to do this with my setup, thanks for the reminder. Amazon order placed!

 

[griffths]

Likewise, this has been on my to-do list for a while and since Spring has sprung I am getting into the thunderstorm season.

I followed what @camerafool spec'd out but made a few minor tweaks to save a few bananas and satisfy my OCD for OEM products.

Total for the parts below came to around 60.00 shipped because I was able to find an open box on the TP-Link media converter from Amazon Warehouse Deals.

• 2 Meter Multimode Duplex Fiber Optic Cable
• TP-Link Gigabit Ethernet Media Converter
• Cisco GLC-SX-MMD SFP 1000Base-SX Short Haul Multimode Module with DOM

Something important to keep in mind if you are considering this is to ensure that your cable modem (or whatever component you are isolating) has a Gigabit Ethernet port on it or the media converter I listed won't work as it ONLY supports Gigabit Ethernet on the copper side and, of course, your network switch must have a SFP port on it to accept the SFP module if you follow my recipe above.

 

[aristobrat]

Done! I might have to rethink that 1ft fiber cable though, ... or at least move it to the lower port on the top switch. yipes

 

[camerafool]

If your switch doesn't have SFP port, you'll need two media convertors.

 

[griffths]

If your switch doesn't have SFP port, you'll need two media convertors.

I still believe my caution regarding the need for Gigabit Ethernet is accurate but maybe you can confirm if those media converters are autosensing on the copper side. It is my understanding that they ONLY work at Gigabit speeds on the copper side and so won't work in 100Mbit equipment.

 

[camerafool]

It is my understanding that they ONLY work at Gigabit speeds on the copper side and so won't work in 100Mbit equipment.

^^ this is correct, I tested my TP-Link MC220L convertors and 100 won't work. There's a model MC100CM with 10/100Mbps specs.

 

[griffths]

@camerafool, thanks for confirming that. It isn't totally clear on the Amazon website and it will save folks here the hassle of buying an incompatible media converter.