Grounding a Small Network Across Two Buildings

[JRRB]

I'm trying to centralize our network wiring that currently has 5 switches among 2 floors - no home-runs. I'm also trying to network a 2nd building 125ft away for which there is already empty underground PVC conduit running from a shed attached to Building 1 and the basement of Building 2. There will be about 22 drops in Building 1 and 10 in Building 2.

Sketch of setup:

http://www.mediafire.com/imageview.php?quickkey=ohm5eq2rmmm&thumb=6

An OFNR, non-conductive fiber optic cable, with a transceiver at each end will connect the 2 buildings. I choose fiber not for speed but so I don't have to worry about lightning protection, differing ground potential, etc. (right?). Everything else will be Cat5e.

Is it necessary to ground the patch panels and transceivers if the items have no manufacturer specified way to do so? Are the grounded plugs on the switches sufficient?

Building 1:
A single 24-port patch panel mounted on a 1U metal wall bracket
24-port switch with metal chassis and grounded plug attached to a 1U metal wall bracket

Shed attached to Building 1:
Surface mount 12-port patch panel
Transceiver, likely a metal chassis but no ground plug

Building 2:
16-port switch with metal chassis and grounded plug, mounted on a 1U metal wall bracket
Surface mount 12-port patch panel
Transceiver, likely a metal chassis but no ground plug

I have searched online and the NEC for days on this topic and can only find information on larger setups with dedicated telecom rooms, large racks, grounding bus bars, etc., but nothing on small setups.

I've found some do-it-yourselfers online who have grounded things by running a wire from the chassis, rack, etc. to a screw on the nearest grounded outlet, but for some reason this seems incorrect to me.

I can see a fat stranded cable coming out of large electrical panels in the basement and shed. In both places they are attached to a copper water pipe via a clamp with two screws. Our phone system is also connected to this ground. I THINK I read somewhere the proper way to ground equipment is to run a wire from whatever it is you are grounding directly to this ground. Is this necessary for my setup? How am I suppose to do that? What could go wrong if I do/don't?

 

[wires]

Good for you! Using fiber between buildings is the correct thing to do.

Are the shed and building one on the same electrical ground? If not another bit of fiber is a good idea.

As long as you are plugging all equipment that comes with grounded plugs into correctly grounded outlets you should be fine.

 

[JRRB]

Thanks, wires. Yeah - the shed and building 1 are on the same ground.

Grounding my three small patch panels seemed like overkill to me but just wanted to make sure.

 

[mikeydidit]

I agree with wires, that fiber runs was a good way to go with this. It boils down to about the same money vs. copper and protection. Plus you now have overhead in way of speed of connections. You didn't mention which mode of fiber you are going to be using (single or multi (50 or 62.5). On a short run like that one you should be able to do a GIG no problem. If you see needing 10 GIG later then you may want to install SM.

The only other thing i would mention (as it looks like you on the right path) is to go with a indoor/outdoor rated fiber. This will keep you from having jelly filled cabling. High smoke cables (PE) in commercial buildings must be terminated within 50 of the building entrance or be ran in rigid conduits.

When is the last time you helped someone, just because you were able to?

For the best response to a question, read faq690-6594

 

[JRRB]

Thanks, Mikey. I was going to go with 62.5 multimode with SC connectors to go with the transceivers. The transceivers will limit the speed to 100Base-TX, but that will be fine for our purposes. I only went fiber to avoid grounding/lightning issues, which is why I went with a cable with a non-conductive sheath.

Cable:

http://www.l-com.com/item.aspx?id=1751

Transceiver:

http://www.newegg.com/Product/Product.aspx?Item=N82E16833156006

Perhaps I am choosing the wrong cable though. My current plan is to have the fiber terminate within feet of coming out of the conduit, locating the transceivers in the basement and shed. I suppose if I went with an indoor/outdoor cable, I could run the fiber all the way into building one and put the transceiver by the main patch panel. Maybe this breakout cable would be better?...

http://www.l-com.com/item.aspx?id=1578

... if L-Com will put connectors on for me. It appears to be beefier for outdoor use but will still let me use indoors like you said. I'm looking for a $2 to $3 per meter price. Thank you, again.

 

[JRRB]

Now that I found l-com's custom order selector, running the fiber inside building one all the way to the main patch panel will be a little too expensive. I also realized the connectors will make it difficult to run into the building. So it will be terminated within 10ft of coming out of the conduit like I said. I still may go with the breakout cable if it's better for outdoor use than my original selection.

 

[mikeydidit]

The breakouts are good (and sometimes necessary) on very high speed applications. I don't see the added expense for 62.5 MM. We usually use those on SM for over 10 gig connections.

Here (and if this were my project) i would have a minimum 6 strand (and I agree that 62.5 is good for most applications) pulled into this building all the way to the patch panel. Then have it terminated with whatever ends you choose.

This does several things.

1. 1 less patch place and one less place to use patch cords = 1 less place for trouble.
2. When the contractor is through terminating, these connections and total length of the fiber run is shot with a OTDR to make sure 1. the cable is good and 2. the ends that were terminated are good (around less than .5 DB loss.)

Then you will have something trouble free until someone with a backhoe finds it for you..

When is the last time you helped someone, just because you were able to?

For the best response to a question, read faq690-6594

 

[JRRB]

Thank you for all the info Mikey. Since I'll be doing the install myself and have no fiber experience (or fiber testers), I was going to get pre-terminated cables. It's obvious I'll have to consider this portion of the project a bit more.

 

[wires]

Check out LANshack.com,

http://www.discount-low-voltage.com

or eBay for pre terminated fiber assemblies.

You only need 2 fibers but 4-6 would be nice for redundancy. However it appears that you are only running a short distance (50') so as long as you can replace the fiber easily it does not that big a deal.

It does look like your original cable is actually a patch cable. How do you plan to run between the buildings? Underground conduit?

 

[JRRB]

Thanks, wires. There is underground conduit ready to go, PVC, at least 2.5 inches diameter, and it's empty except a pull line. Several extra conduits too. Running and if necessary replacing in the future shouldn't be difficult. Just want to make sure I don't use something completely wrong. I will check those sites.

 

[JRRB]

Err... the conduit is metal. They screwed some PVC onto the end that does... nothing.

 

[SYQUEST]

You can also check out Fiber Instrument Sales @ 800-500-0347 or fiberinstrumentsales.com, they have Everything fiber! They are very friendly and answer all tech questions.

....JIM....

 

[cwc3]

pull a new jetline along with new run