Fiber

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marley1

Supreme [H]ardness
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Jul 18, 2000
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Hey guys, I have a client who is expanding into the next building. I know everyone here says to run fiber between buildings instead of Cat6 so I was thinking of doing that.

I need to get pre-made fiber cables and 2 fiber to ethernet converters (or may replace both switches with the Dell with fiber.

Any input
 
What are you wondering? The buildings may already have some dark fiber for you, if you don't want to run it yourself.
 
Fiber is always the way to go between buildings.
You will almost always run into ground difference issues at some point, which can lead to network instability, port loss, or even entire switch loss.

I would recommended against premade fiber. It is hard to pull and if it breaks in the middle you are screwed. Get a contractor to run armored fiber (fiber in a conduit) and terminate it for you. It is worth it in the long run.
 
we have a conduit run between both building in a PVC pipe. I need some premade cables that i can just pull through the large conduit.

I looked at some fiber converters have used Trendnet ones before but see it is SC connector.

where can I order premade ones?
 
If you are just going straight through a conduit then premade should work ok, just be careful when pulling.

I would not order the fiber until you know what equipment you are putting on each end so you know what type of connector you will want. You can get adapters and whatnot but I prefer to avoid them when possible. If you can spare the cash I would pull 2 lines just to be safe. I prefer to always pull at least one extra; I always end up using it later on down the road.

I used to get my fiber from cablestogo but I have switched to monoprice. price is less than half but the cables identical.
 
If you can't get fiber between the buildings but have Cat5/6 available you could create a simple optical isolation, like this:

Get a POE fiber media converter (converts Cat 5/6 RG45 to fiber). Run your cat5/6 between the buildings. On one end terminate it normally but include a POE injector - either a dedicated injector or use a port on a POE switch. On the other end DO NOT CONNECT IT ELECTRICALLY to anything in the building - connect it only to the POE fiber media converter - then run a short fiber connection to your network in that building. Your choice to connect to existing fiber termination on a switch or use another media converter. This method gives you electrical isolation between the two buildings but you don't have to run new fiber between buildings to get it. Very important that the only electrical component that is not isolated - the media converter - is powered via POE from the other building. Otherwise you defeat the whole purpose by creating a power/ground tie between the buildings.

One remaining risk - how much you care probably depends upon exactly where your buildings are. A lightning strike outdoors anywhere near your inter-building conduit could be a bad thing. If you are at any risk of lightning I'd suggest running the Cat5/6 connection on BOTH ENDS though an appropriate protection device.

Of course - at the end of the discussion - the best way to achieve electrical isolation is to run fiber between the buildings and don't put any copper in the inter-building conduit. I only offer this suggestion in the off chance that becomes impossible or too expensive.
 
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Anyway to do this without fiber? cost is around 2g, possible to run fiber and then maybe have a like suppressor or something?
 
marley1 said:
sorry can we run cat6/cat5 and use a lightning suppressor?
Click to expand...

The problem with copper is two-fold:

1. Ground potential differences between the buildings. Putting wire between your nodes where there might be ground potential differences risks putting voltage onto your cat5/6 cable. And I don't mean just a little bit of voltage - in some cases it could reach levels that puts your equipment at risk, possibly including the risk of smoke and fire. The only way to fix this either with a pure fiber solution or an 'optical isolation' solution as I described my previous post.

2. Induced surge (aka lightning). You can protect from surge with surge/lightning protectors, but this will do nothing to solve the problems of ground potential differences.

You've got to electrically isolate the buildings. This requires putting something other than wire between them. For this application the only reasonable solution is fiber, either all the way or in the form of optical isolation.
 
marley1 said:
sorry can we run cat6/cat5 and use a lightning suppressor?
Click to expand...

The main issue is not from lighting it is from ground potential differences. The two buildings can be at significantly different potentials due to differences in foundation, soil/moisture content, electrical connections, wind-induced electrostatic buildup, etc. Normally not an issue, it might become one when you provide a really decent path between the two buildings via copper. This can fry equipment in a heartbeat. It may also be against your commercial building code to run ungrounded wire between buildings. Speaking of code I hope the conduit you are planning on using does not contain power lines, this is a big code no no and also a copper networking no no.

I have used something just like the fiber whip you posted in a pinch and it worked great, I was just nervous the whole time I was pulling.

If you choose to run copper between buildings, which I STRONGLY advise against, you can get isolation transformers for both sides but I have never seen one that was rated above 10/100 and have no idea of their reliability or if they even work like they claim to.

The thing to ask yourself or to convey to your manger is this: Is it worth saving $1000 now to run copper only to have to replace switches, servers, and computers down the road that were killed by grounding differences or lightning traveling down an ungrounded wire?
 
schnell said:
...If you choose to run copper between buildings, which I STRONGLY advise against, you can get isolation transformers for both sides but I have never seen one that was rated above 10/100 and have no idea of their reliability or if they even work like they claim to...
Click to expand...

Isolation transformers do not work for balanced-line digital signals. Won't work be 10, 100 or 1,000 base-t. Optical isolation is the only workable solution - and as everybody has said its best of you just do it optical all the way between buildings.
 
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