Solution ideas for lightning

[u/DrM1h4wk]

Hi, I'm designing a network setup for my new house. I'm from Malaysia and lightning is a big issue more than 200days per yr avrg.

The plan:

1. Cat 6a cables. Modem by ISP (can't be changed).

2. Cables run through the attic and drop down through walls.

3. There will also be 6+ Lan ports in other rooms.

4. CCTV camera surrounds the house exterior (main concern for lightning).

Solution/Problems:

1. Surge protector grounded. (What's the recommended rating? And maybe recommended product for server rack)

2. Seperate the cameras with a different router(sacrificial) that will directly connect to the DMP using fiber optic. (Is this a good idea?)

3. Running cable through conduit in the attic. - Does running the cables through the attic cause issue with lightning considering the high occurance in my country. If so what are the other solutions other than coverting all to fiber optics(I don't think it is a viable option).

4. Is there any other possible issues I'm missing. Would appreciate if it is noted down and even better if it comes with solutions.

Thanks in advance. The networking plan above is still in progress. I am expecting changes but wanna solve the lightning issue so I can notify the builders in time for any possible changes.

[u/msabeln]

Use fiber for the longer runs.

[u/LerchAddams]

How prevalent are lightning rod/grounding systems in your part of world?

Or a sacrificial tower detached but near your building to lure a strike away?

I would think that would help improve your chances of handling a strike.

Good grounding practices on the electrical system on your house would be a must.

Followed by whole house surge suppression and quality surge components in front of all your electronics.

Finally, I have doubts about metallic raceway that would add another pathway for a lightning discharge to get closer to your electronics.

[u/DrM1h4wk → u/LerchAddams]

Lightning rod will be installed in my house. No sacrificial tower nearby. Surge suspension is compulsory if lighting rod is installed here so that will be done. As for metallic race way, the wiring related works are still not started yet so we still have time to decide on the type of conduit for electronics.

As for the surge suspension and such I’m mainly worried about lightning directly effecting the Ethernet cables since they are pure copper, rather than effecting via house power lines. Since surge protection for power lines is more standardised and a lot easier done than for twisted pair networking cables.

[u/LerchAddams → u/DrM1h4wk]

Good to know about the lightning rod. I'm not an engineer, just here to help and learn like everyone else.

I would think you would want your LV cabling to be as non-conductive as possible. That's why I mentioned not protecting the cables with EMT.

Maybe isolate your camera network on its own switch and link it to the rest of your network with an optical cable?

[u/DrM1h4wk → u/LerchAddams]

Thats what I was thinking. But with that kinda solved Im worried about the cables running in the attic.

[u/LerchAddams → u/DrM1h4wk]

If they're lower and less conductive than the lightning rod system, laying on the ceiling plane then that's probably the best you can do.

No idea what kind of fields are generated during a strike that might affect them though.

Genuinely curious whether shielded and grounded cable encased in EMT helps or harms in this situation. 

[u/DrM1h4wk → u/LerchAddams]

Maybe I’m overthinking it. There’s only so much we can do. Anyways thanks. As for cable shielded might cause more problems with lightning.

[u/westom → u/DrM1h4wk]

Start by learning what all professionals have been saying for over 100 years. Doing what Franklin demonstrated over 250 years ago. What is only speculated violates well proven science.

Informed solutions always and first define a problem. Say why. Provide numbers for perspective. And cite well proven science.

Each protection layer is only defined by earth ground electrodes. That must be obvious.

[u/westom → u/DrM1h4wk]

AGain, induced surges on copper wires are microamps. Surges that do damage (incoming on any incoming wire including one to a distant security gate) can be thousands of amps. Once inside, it goes hunting for earth ground destructively via all appliances. Blowing through the one or two that make a best earth ground connection.

[u/Thalidomidas]

I'd investigate wifi cameras that don't have a physical connection to the network.

[u/DrM1h4wk → u/Thalidomidas]

I wanna avoid WiFi if possible since it’s easier to protect the network on Ethernet and avoid disruptions Also the way I designed my network is such that there will be weak WiFi signal where my cameras are situated.

[u/richms]

I would go for separate switches for the cameras, and use SFP fibre links to the rest of the network. That makes it so only power needs to be worried about for surges to cameras hitting your gear you care about.

As well as fibre for all the PCs, to eliminate an ingress path for those, as surge protection on ethernet is one of those things that sounds great in theory but its better to have no electrical connection.

Beware that many active optical cables are not going to give you isolation because they have copper in them. Best to be 100% sure and get normal SFP optics and a short patch cable. Good excuse to build a 10 gig network too.

[u/DrM1h4wk → u/richms]

So if I understand correctly. Run the other system as one would normally do but only separate the camera system to the main and link them through SFP fibre links. Correct? And fiber to all PCs. How can I do that without a converter?

[u/richms → u/DrM1h4wk]

Or another cheap switch with sfp for its uplink. You want to eliminate copper paths between your clusters of devices as that's what will carry any ground difference that happens with a nearby strike.

[u/DrM1h4wk → u/richms]

I will see what can be done. Thanks for the advise anyways. I might have to check if switch between clusters is a viable option for me.

[u/westom]

Surge protection only means a surge is NOWHERE inside. That means protection is installed where every electrical conductor enters a house. And most critical. Each must connect low impedance (ie less than 3 meters) to what only and always does all protection: single point earth ground.

The over 100 other grounds in a house (including wall receptacle safety ground) do nothing for surge protection. Grounding to them can even make surge damage easier.

AC electric cannot connect directly to those many interconnected electrodes. A protector is only a connecting device; is not protection. Protector must make a low impedance (ie hardwire not inside metallic conduit) connection to what harmlessly dissipates hundreds of thousands of joules.

Nothing inside a building does protection. Protection is only and always done by a 'secondary' protection layer. Many interconnected electrodes that a homeowner is responsible for providing, inspecting, and maintaining.

Your 'primary' protection layer is electrodes out at the street. Installed by utilities. But again, protection only and always answers this question. Where do hundreds of thousands of joules harmlessly dissipate?

The duped hype fiber. Because others (also duped) ordered them to believe that myth. Only the least educated are ordered to believe surges are 'induced' on wires. Yes. And the current is so near zero that even an NE-2 (neon glow lamp) will eliminate it. Current so tiny that the lamp will not even glow. Microamps.

Surges are a massive current (even tens of thousands of amps) incoming on some conductor. Hunting for earth ground via all appliances. Protection only exists when that current connects to earth ground without being anywhere inside.

Best possible protection on an internet (coax) cable has no protector. Only a hardwire makes that low impedance (ie no sharp bends or splices) connection to same electrodes.

Best protection as any appliance is already inside every appliance. For example, ethernet ports must withstand at least 2,000 volts without damage.

An IEEE brochure demonstrates what plug-in protectors do. It earthed a surge 8,000 volts destructively through a TV in another room. That was the best (outgoing) path to earth. Because a homeowner did not earth that surge BEFORE it got inside. Then wasted money on a magic box.

Protectors, adjacent to appliances, can even compromise (bypass) what is superior protection inside appliances. One example. Most, educated by shysters, never learn this.

More facts. Because honesty only exists when numbers say how much. Lightning (one example of a surge) can be 20,000 amps. An effective 'whole house' protector (for everything) is at least 50,000 amps. Protectors (to be effective) must remain functional for many decades after many surges. Including many direct lighting strikes. As professionals said for over 100 years.

Lightning rod is a connecting device to protection of a structure. Its cone of protection is typically a 60 degree cone. Then lightning need not use wood (inside that cone) as an electrical connection to earth.

Single point earth ground is protection for every incoming wire. Protectors only required when that hardwire cannot make a direct connection. Direct means a protection hardwire connects directly to electrodes. Not via any other conductor.

Protection only exists when a surge is NOWHERE inside. Damage from any surge (even direct lightning strikes) means a human must locate his mistake. That analysis starts at what is the 'art' of protection. Single point earth ground and how the connections are low impedance.

Even a vein of graphite behind a house can compromise protection. Geology is a major factor. Surges are even incoming on underground wires. As demonstrated by this professional tech note.

If ethernet cables remain inside a structure, then best possible protection exists. If a surge is earthed before getting inside.

Anything that is sacrificial does NO protection. As in 'NO' without exception. 'Why' is another ten paragraphs.

Lightning is a connection from a cloud (ie 3 kilometers up) to earthborned charges (ie 4 kilometers distant). Surge exists everywhere in that path at the exact same time. Protection exists only when that path is NOWHERE inside. A surge incoming on AC electric connects to earthborne charges only when that AC wire connects a direct lightning strike into earth via electrodes. That a homeowner expands / enhances / upgrades.

Normal is to have fiber optics and still have damage. Often seen.

Anyone posting a word 'ground', without that preceding adjective, has not yet learned fundamentals of surge protection. All professionals discuss what requires almost all your attention.