Is this fibre cable toast?

[OrangeX]

Me and my dad have been wanting to do a network upgrade for some time and last Saturday. We laid a fiber cable through a cable conduit going through our house and after we were done, we realized the outside had cracked. On the packaging it just says that it's a multimode simplex 850nm OM4 cable. On the inside i could see a blue-green wire like thing that did not look damaged.

When I asked on Discord, I just got a "Yeah, probably broke", so I'm asking here now. It wouldn't be the end of the world, if it was broken but we would have to lay the ca. 3,5m of cable again through a tight conduit.

 

TL;DR is this cable broken?

[Aaron_T]

The only way to be sure one way or the other is to plug it into a tester. But likely yes, it is. Better question though, after going to all that effort to get a fiber network setup going, would you really want to risk leaving that cable in place even if it did test good?

[Skiiwee29]

yes, shes broke. Fiber is very sensitive to any bends, kinks etc.. this is well beyond that. 

[Electronics Wizardy]

Yea looks bad, you can test it, but even if its works id replace it.

 

THere is cabeling that is made for pulling through conduit, id get that s a replacement.

 

 

[OrangeX]

I didn't specify but it didn't break in the conduit or while pulling it through the conduit. While it was hanging on a sharp edge, my dad or me pulled on it to hard and it broke, we'll be getting the same cable as the fit is VERY tight.

 

[Electronics Wizardy]

12 minutes ago, OrangeX said:

I didn't specify but it didn't break in the conduit or while pulling it through the conduit. While it was hanging on a sharp edge, my dad or me pulled on it to hard and it broke, we'll be getting the same cable as the fit is VERY tight.

 

Id still get a cable made for conduits if sharp edges are a issue. There much better at handling stuff like that.

 

Also id personally run single mode, as I don't see a reason to go multimode, but you do you.

 

 

 

 

[OrangeX]

I'll update you when I can check if it works, will definitely replace asap (probably not with multimode or shielding because we have very specific networking hardware on one side)

[OrangeX]

You all doubted me, but it works perfectly without any problems at 10gbit

[Alex Atkin UK]

15 minutes ago, OrangeX said:

You all doubted me, but it works perfectly without any problems at 10gbit

Its more that you've destroyed its protection and potentially could degrade further over time, or cause drop outs due to errors.

[OrangeX]

Obviously we're gonna shield it with plastic to protect it.

[Jameszy]

why use undersized conduit? the stuff is cheap.

 

"Link On" sounds like its trained at 10g, but ive had ethernet cables train at 1g and not give me the thruput... YMMV..

 

whats 4m of fibre cost? why not just pull a new cable and not risk future issues?

[Falcon1986]

1 hour ago, OrangeX said:

Obviously we're gonna shield it with plastic to protect it.

If replacement of 3.5m of fiber and labour is going to be expensive and your workflow that depends on this fiber connection isn’t critical, then you can do your patch-work and hope it continues to perform as it should. But I can assure you that the manufacturer wouldn’t be able to back up rated performance while the cable is in its current condition.

 

That being said, what you have now might last 5 years before showing signs of degradation rather than 10 years. Fiber uses light for communication, and the direction that light travels can change dramatically if it encounters any little defect in that fiber housing. While the link status shows 10Gbps, you won’t know the quality of data transmission until you really start using it and find out that you’re getting a lot of corrupt data... at 10Gbps!

 

If the folks on Discord warned you already and you’re still not going to heed similar advice given here, then the consequences are all on you.

[OrangeX]

Clarification: the conduit is 3,5m long and can't be replaced. The cable is 30m long and must be entirely pulled through from the top. The house was built in the 60's and the last time someone changed the conduit to one bigger was 20 years ago.

[tt2468]

I'm gonna go ahead and disagree with a lot of the users in this thread, the fiber could very well be fine. Only way to test would be to plug in your transceivers and see if a link pops up.

 

As you saw, it works fine. Modern fiber is incredibly tough against bends, kinks, and all kinds of abuse. What you want to avoid is having a kink in your fiber during normal operation, but it's actually difficult to break modern fiber like om3/om4.

 

On 2/24/2021 at 8:55 AM, Jameszy said:

"Link On" sounds like its trained at 10g, but ive had ethernet cables train at 1g and not give me the thruput... YMMV..

Fiber can't really be compared to ethernet in this way. With fiber, it's either broken or it isn't. The only way you can get performance problems is if your cable is kinked to a quite extreme amount, where you get significant enough signal attenuation for the transceivers to not be able to compensate. I've had scenarios where cables were chewed on and damaged in a very similar way to OP, and those cables are still working great to this day. Just a few days ago I pulled some SMF through a quite busy 1" conduit and it got bent in half during pulling, but the actual fiber is completely undamaged.

[OrangeX]

It was working for about a week until it wasn't because we had to do something unrelated, pulled on it and broke it. We replaced it and it now works without any problems. The cable was not broken in that picture, it only broke later.