Long Cat5e runs

Feb 13, 2006 10 Replies

Hello all: I'm connecting 4 adjacent houses to a broadband satellite feed thru a Dlink DI-604. The cable runs will be 275ft, 190ft, 175ft, and 150 ft. Cable is standard cat5e flooded. Should this setup work ok?



snipped-for-privacy@yahoo.com wrote in part:

It might work, but not for years. The lengths are well within spec (100m).

The weakness is lightening protection. Any nearby (~150m,

1/2 second) lightening strike is very likely to fry ports/cards.

-- Robert

Didn't consider the lightning issue.... Any way of lessening the risk?

Fiber or wireless.

Anything with copper means the person with the weakest protection will allow it into all.

I'd up the other fellow's range to anything within a 1/2 or more. More if it hits a power line.

Can you get reasonable line of site to the various places from the home base. Especially a winner if you can get it to all from the same spot. Best from a setup point of view is if you can "see" everyone from a thin wooden attic gable.

The best way is to use fiber.

Use grounded lighting protectors (something like:

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there are plenty of other alternatives) Bury the cable in conduit.

A direct hit is always going to fry your equipment. A near miss probably will fry some things (but at that point your network will be the least of your problems (ie. your other household electronics)).

Thought about wireless, but very thick tree coverage; no LOS. Cable will be buried about 1 ft deep. Would standard emt conduit shield it from induced charge?

snipped-for-privacy@yahoo.com wrote in part:

No. The problem is not induction. The different building ground-stakes will be driven to different potentials during a nearby strike. Then the Cat5 becomes a ground-path.

-- Robert

This really isn't a problem. Ethernet is transformer coupled and as long as you use proper grounding (both the house and ethernet service entrance) it'll be OK (a direct hit will almost always fry something, and the electrostatic discharge from a near miss.will probably fry something (although it might not be obvious why your computer keeps randomly crashing)).

If this was a problem, then we wouldn't have telephone/DSL or cable TV service (or satellite dishes), etc.

none wrote in part:

With something like 500V isolation and perhaps 1500V breakdown. Almost nothing during a lightening strike when ground gradients are kV/m

Correct, if you can find Cat5 ethernet protectors and put the service entrance close to the groundstake. Unfortunately, many people think they can run wire without these precautions.

-- Robert

And what most folks don't know is that the MOVs wear out over time. And even with these you can still get differential voltages as you have two paths into each house. One from the power, one from the Ethernet.

As long as they are all tied to the same ground potential for the house there is a very very very much reduced potential voltage differential spike. But when you tie multiple houses together with multiple service entrances, it gets much harder.

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