My Home Fibre Network Disintegrated

I have fs.com armored cable installed for 10 years now. Different times and spools. It is all in perfect shape. They test all their cable. Something is almost certainly disintegrating your cable. If you have any spare old pvc pipe or something in the basement, hit it with a hammer and see if it is brittle (the hammer should bounce). If it is brittle, I would not hang out in the basement until you figure out what is going on.

One random guess other than gases of various sorts: If you have the lights on a lot, it's possible you have lighting that is not properly uv filtered somehow.

(It theoretically could be lots of heat/humidity vs certain types of cable jackets, but that would be obviously noticeable most of the time)

The fiber and even the armor itself looks fine in your pictures and I bet the error rate is zero. Outside of bending, i can't see how you could damage the fiber when the armor is in perfect shape. That armor will unravel if you really damaged it. The speed thing is not how fiber works. It's hard to get marginal link enough to generate retries that degrade your speed by 10%. Most of the time either you have full speed link, no link, or so many errors speed is zero. The optics almost always have rx/TX signal strength DDM you can look at

Also did you say you direct buried it in cement? If so it's not rated for that. Direct burial and concrete tight/safe are not the same thing at all, not the least of reasons being concrete is highly alkaline (ph12-13) when poured

Thanks HN folks for all the comments. To clarify a bit, the cables are pulled through PVC conduits under the flooring before being buried in cement. Currently the hypotheses for why the cable disintegrated so quickly is hydrolysis and paint solvents. Singapore is extremely humid but this doesn't explain why the exposed cabling on the other end is still healthy and not crumbly.

The second possibility is that I keep the leftover wall paints (Nippon Paint Vinilex 5000) in the same room and have noticed that much of the solvents have evaporated. It is possible that the solvents in the air might have caused the cable to fail in 3 years. It would explain why the other ends that aren't exposed to the air inside the bomb shelter aren't falling apart.

Some other learnings from this. Buried cabling should always be permanently fixed and attached to a patch panel instead of dangling in the open. That was the original plan but I figured it wouldn’t be an issue. I was wrong. Always measure exact length of buried fibre cabling as they aren’t meant to be stored in loops.

If you buy a consumer product labeled "military grade" you are buying snake oil. And not just snake oil, incredibly over priced snake oil.

Looking at the pictures it looks like the fiber itself might be inside of that spiral metal conduit in the middle and the outside is just abrasion protection. There are way too many strands for that outside bit to be the fiber. It's obviously bad that the outside plastic disintegrated, but it looks like the buried cables might be fine.

I have a similar problem on my car where the 12v wiring is disintegrating like this because the manufacturer tried to switch to a more environmentally friendly wiring. Now the wire jackets turn to dust at the slightest touch or if they vibrate too much. I'm forever tracking down intermittent shorts in the wiring harness.

There's no link to the data sheet of the actual cable, but, yeah, looks like this should not have happened in such a short timeframe unless there's something really funny going on in that room, like ambient temperatures above 50 degC.

Another thing that should not have happened is installing the cable in loops in this way: any 'building' or 'underground' type cable needs to be of the exact length required at the demarcation point, fastened properly to prevent movement and terminated on a proper patch panel (can be a one-port box-type thingy for small setups), from where you use regular patch cords to connect your equipment.

(Loops are definitely allowed though, but that use case is mostly for aerial fiber to enable repair splices, and there are some very specific bend-radius and strain relief requirements, which, again should be spelled out in the cable data sheet)

Andromeda strain

That seems incredibly fast for plastic to degrade like that. I wonder if you could have something generating ozone in there.

From the photos, it does not look like the fibers themselves are damaged. You should check the error rate on both sides. If it is 0, the not optimal values of your speedtest are not related to your fiber. If it is not 0, the more likely issues are in order: connectors to clean (buy a cleaning pen), bend radius somewhere, faulty optics, then the fiber. You can also pay a professional to run an OTDR on your fiber. It would show where the fiber is degraded.

Regarding the last few sentences about the speedtest, Fibre doesn’t degrade in a way that you get 30 to 40% line speed. DSL did that, fibre doesn’t.

Speedtests for 10G are complicated and will show low numbers because of all the different TCP parameters and schedulers. Sometimes because peering links of your ISP or the speedtest providers are saturated.

I’ve had this failure on soft-touch usb cables from the 2000’s, not related to movement, just in a box in room temperature storage they disintegrate like this. It was described to me as thermoplastic elastometer degradation but I’m not really satisfied with that vague of an answer. Main comment thread when I first jumped in to discuss it: https://news.ycombinator.com/item?id=28054090

There are very survivable fiber cables designed for stage and A/V setups for instance, and even "real" military grade ones. But the common thin LZSH stuff is surprisingly resilient in my experience, so long as it didn't kink the OP would probably have been fine with a "standard" cable. In any case I would always try to place fiber in a place where it can be re-pulled.. conduit, tray, or a plenum.

I bought a big spool of 6 strand Corning stuff a long time ago for various projects, the cost and diameter don't increase much to add some protection lines even if you never imagine using them they can save you a re-pull if you bugger something up in construction.

Fs.com are a well regarded company. The OP should contact them and see if there's a recall on those cables or something. Sounds similar to what happened with some mains power cables sold by a hardware store in Australia.

Buried under cement/concrete. A good reminder of the benefits of planning to install some conduit.

I believe, he might have stored some solvent in the vicinity of the cable. Anyway it won't affect the optical performance of the cables. It's just the loss of mechanical protection. The disintegrating sheathing could be repaired by shrink tubing, which is more convenient than by wrapping it up in tape.

I sympathise with burying cables that you think are for life, only to need to replace them later.

We ran fibre cables in the ceiling when constructing our house. I requested the electrician to shield the cables with some tubing, but he probably thought I was being extreme. We have 9 cables, 2 of them don't work, likely from being bent by mistake or something.

The wiring is intermixed with electrical and ethernet (for cameras) cables, making the process a bit tricky. At least for us we might only have to cut the ceiling boards in a few places to help guide the replacement cables.

Upvote for posting about a failure. We should all be more vocal about our failures.

Anyone in the US military that has bought 'military grade' Bates shoes and pulled them out of a locker after a year just to see the soles disintegrate can likely tell you the value of 'military grade'.

This is why you always bury a rugged, big diameter tube, and run the cables inside of that.

Is it a humidity problem? in our climate in the Med all kinds of plastic, pu and rubberised materials will just start cracking and flaking after a year or two.

I’d be acquiring or borrowing a fusion splicer and splice protectors then getting them into a fixed enclosure on the wall with socket outlets.

It seems like wizardry when you first see it, but actually fusion splicing fibre is not hard at all once you’ve done it a few times.

The most important part is the cleaving, always use a high quality cleaver.

Chances are very high the fibres themselves in the cables are absolutely fine, they are remarkably resilient given their size.

The link to the product says "TPU outer jacket". That's thermoplastic polyurethane, which is well known for degrading via hydrolysis:

https://en.wikipedia.org/wiki/Polyurethane#Hydrolysis_and_bi...

...so it is a bit amusing to see "TPU Jacket Features Water, Abrasion Resistance" in the product description. PVC or PE would be far better and more common.

> A main component of why I was in sheer horror was the fact that I had stupidly buried all of these cables under my cement flooring in PVC trunking from my shelter to all of the rooms in the flat.

This I don't quite get .. as I understand it "PVC trunking" is a type of cable channeling / ducting.

I do a lot of cable and pipe layout around houses, farms, workshops, worksites, etc. and it's routine to use pipes / ducting / channels to allow other cables to be threaded through after or to replace bad cables.

As much as cable deterioration sucks it should be a relief to have ducting to pull good through after the bad.

This looks like regular hydrolysis, same thing that happens to shoe soles after any number of years.

I don't think it's fair to make fun of the cable specifications, seems to me they held up just fine despite the jacket disintegrating. The article doesn't mention the error rate, but I wouldn't be surprised if it was still zero.

Would that be this item? [1] The product description and SKU match.

It's not clear who "FS" is. A reseller? A manufacturer? They seem to be in Singapore. There's no excuse for the external plastic sheath disintegrating. They must have formulated the plastic wrong. The terms specify a 30 day warranty.

Here's a catalog of real mil-spec fiber optic cables.[2] This is overkill for home applications; you put these in a fighter jet.

In between are Telecom Industry Association compliant fiber optic cables. That's what telcos use. There are US manufacturers with real plants and addresses.

[1] https://www.fs.com/products/70220.html

[2] https://www.glenair.com/catalogs/fiber-optics.pdf

That's weird. Only place I've seen a rapid degradation of cables were those getting direct sunlight.

The conclusion paragraph seems doubtful to me though - unlikely that speeds will slow down from a cables external plastic flaking

Was there a technical reason for not using corrugated ducts in the concrete, maybe because it's a shelter?

What’s the advantage of using fiber optics for home networking over 10Gbe Ethernet?

FS.com is great for all kinds of fiber stuff… but curiously, nothing long-distance. I never really understood it; you can get a 40-channel DWDM setup (including tunable 100gig SFPs) just like nothing, but a drum of quite normal G24 loose tube cabling meant for outdoor use? Nope. You'll have to go elsewhere for that. And I guess that's also what happened here; the poster picked the best thing they had for the purpose, and it's just not that good.

I've also had problems with their pigtails also being weird, by the way (layers separating so that automated cutters can't stretch the pigtail properly). It's weird when everything else is so good—it's as if they only care about what's going on internal to a data center and you never need to do a splice. :-)

This is why should never-ever directly bury cables in the ground/walls/floor and ALWAYS use rigid PVC and/or flexible PVC tubes from site to site and pull the fiber or UTP cables through those tubes.

As an alternative if you are networking a single location and you don't mind seeing some finishing profiles on the walls (or want something easy in a pre-existing situation) you can also drill somewhere along the wall and feed the cables directly down to the floor or up the ceiling and cover them up.

But always, ALWAYS, make them easily accessible and easily removable.

Got plenty of experience to say no cable will survive a lifetime, and if you experience a problem without easy access you are fucked.

The coils are too tight. The tension on the plastic pulled it apart.

FYI "military grade" is code for "cheapest bidder."

If it's any consolation, you can have fiber without jackets as long as they are cable-managed very carefully.

When you design, build or renovate your house, always plan for future replacement of cables and pipes!

Coiled up high-speed fiber optic cables suffer data-abrasion due to centrifugal forces. Either reduce data speed or arrange those cables in straight lines with space-grade angle connectors.

If the point of a home lab is to learn useful lessons where your customers don't pay for your stupidity (or more politely: your learning journey) then this guy's next employer is definitely getting their money's worth.

But that reminds me of something: I spend money on hobbies, but I spend the absolute minimum amount of money possible on home IT research and learning. Fuck that noise: if my employer wants a lab, they can damn well pay for one.

> military grade cable

Bruh