Fiber-optic isolator?

Do any of you know of a small (read this as short) fiber link I can use
on a long CAT-5E line to isolate two buildings' routers/hubs from ground-
potential variations that might cause wire-connected equipment to fail?

My idea is to run Cat-5 for the long line, then insert a Cat-5 to fiber
to Cat-5 link somewhere in the line as the electrical equivalent of a
"thermal break". My reasoning is that I already have the copper, and
fiber over 500' would be quite expensive. Correct me if I'm wrong.

I live in a lightning zone, and the two buildings are on different
transformers, so the potential differences could be large.

Thanks,

LLoyd

On Wed, 06 Feb 2008 19:24:57 -0000, "Lloyd E. Sponenburgh"
<lloydspinsidemindspring.com> wrote in
<Xns9A3C92AE2CB41lloydspmindspringcom@216.168.3.70 >:

>Do any of you know of a small (read this as short) fiber link I can use
>on a long CAT-5E line to isolate two buildings' routers/hubs from ground-
>potential variations that might cause wire-connected equipment to fail?
>
>My idea is to run Cat-5 for the long line, then insert a Cat-5 to fiber
>to Cat-5 link somewhere in the line as the electrical equivalent of a
>"thermal break". My reasoning is that I already have the copper, and
>fiber over 500' would be quite expensive. Correct me if I'm wrong.
>
>I live in a lightning zone, and the two buildings are on different
>transformers, so the potential differences could be large.

<http://www.transtector.com/productdata?class=ALPU>

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John Navas <(E-Mail Removed)> fired this volley in
news:(E-Mail Removed):

> http://www.transtector.com/productdata?class=ALPU

Thanks. I've used Transtector plug-in protectors with good success.

I was looking for something more in the line of "non-sacrificial"
equipment, though.

The cheapest multi-mode pre-terminated fiber I can find (with a pulling
eye) is about $500 for a 400-foot run. Then two media-converters add
another $150, or so.

I was hoping there was a "link in a box" arrangement for this very
purpose.

John, have you used the Transtectors for this purpose? If so, how do
they hold up to nearby cloud-to-ground or cloud-to-powerline strikes?

LLoyd

On Wed, 06 Feb 2008 20:54:05 -0000, "Lloyd E. Sponenburgh"
<lloydspinsidemindspring.com> wrote in
<Xns9A3CA1CA830D6lloydspmindspringcom@216.168.3.70 >:

>John Navas <(E-Mail Removed)> fired this volley in
>news:(E-Mail Removed) :
>
>> http://www.transtector.com/productdata?class=ALPU

>John, have you used the Transtectors for this purpose? If so, how do
>they hold up to nearby cloud-to-ground or cloud-to-powerline strikes?

Yes. I've not had one die, but then we don't get many thunderstorms
around here.

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They make media converters. They're CAT5 10/100 on one end and fiber on the
other. You can span up to 1km with them. Allied Telesyn made some decent
low-end ones. Check eBay for them. Then you'll need the fiber cabling, and
have it terminated with the appropriate ends for your media converts (often
either ST or SC connections). When you pull (or bury) the fiber consider
getting a bundle with more than just one pair. If a fiber should break
you'd want a spare in there. I'd pull at least a 4 strand.

-Bill Kearney

"Bill Kearney" <(E-Mail Removed)> fired this volley in
news:(E-Mail Removed) t:

> They make media converters. They're CAT5 10/100 on one end and fiber
> on the other. You can span up to 1km with them. Allied Telesyn made
> some decent low-end ones. Check eBay for them. Then you'll need the
> fiber cabling, and have it terminated with the appropriate ends for
> your media converts (often either ST or SC connections). When you
> pull (or bury) the fiber consider getting a bundle with more than just
> one pair. If a fiber should break you'd want a spare in there. I'd
> pull at least a 4 strand.

Yes, that's the other viable option. I haven't gleaned Ebay yet for
supplies, but if I buy new 62.5/125um 4-strand cable with SC connectors
and a pull ring, it'll cost over $500 for just the cable to go 400 feet.

It's more of a mental block, I guess, than anything else. I was hoping
for a solution in a box, but when I look at rigging it up myself, then
suddenly I cannot see the advantage of just running a short optical
jumper -- I seem to lean to making the whole link out of fiber, and doing
away with the copper entirely.

Oh, well... I do NOT want to have to replace the components every time we
get a strike on the lines down our road. We pretty much have had to do
that in the past (when on dial-up). Just like the high-speed link will
be, our phones are common to both buildings, even though the power is on
separate transformers; and every time one building took a hit, both ends
got fried.

So I suppose I'll suck it up and go the optical/media converter route.
(yet another $700 out of the construction budget)

LLoyd

On Fri, 08 Feb 2008 12:13:50 -0000, "Lloyd E. Sponenburgh"
<lloydspinsidemindspring.com> wrote in
<Xns9A3E499681DEDlloydspmindspringcom@216.168.3.70 >:

>Oh, well... I do NOT want to have to replace the components every time we
>get a strike on the lines down our road. ...

That's likely to happen in any event unless you install serious
lightning protection.

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John Navas <(E-Mail Removed)> fired this volley in
news:(E-Mail Removed):

> On Fri, 08 Feb 2008 12:13:50 -0000, "Lloyd E. Sponenburgh"
> <lloydspinsidemindspring.com> wrote in
> <Xns9A3E499681DEDlloydspmindspringcom@216.168.3.70 >:
>
>>Oh, well... I do NOT want to have to replace the components every time
>>we get a strike on the lines down our road. ...
>
> That's likely to happen in any event unless you install serious
> lightning protection.
>

That, I can do. I installed medical business-management systems for 22
years here in Florida. The considerations for _guaranteed_ thrice-annual
strikes on incoming service are costly, but do-able.

LLoyd

"Lloyd E. Sponenburgh" <lloydspinsidemindspring.com> wrote in message
news:Xns9A3E499681DEDlloydspmindspringcom@216.168. 3.70...
> "Bill Kearney" <(E-Mail Removed)> fired this volley in
> news:(E-Mail Removed) t:
>
> > They make media converters. They're CAT5 10/100 on one end and fiber
> > on the other. You can span up to 1km with them. Allied Telesyn made
> > some decent low-end ones. Check eBay for them. Then you'll need the
> > fiber cabling, and have it terminated with the appropriate ends for
> > your media converts (often either ST or SC connections). When you
> > pull (or bury) the fiber consider getting a bundle with more than just
> > one pair. If a fiber should break you'd want a spare in there. I'd
> > pull at least a 4 strand.
>
> Yes, that's the other viable option. I haven't gleaned Ebay yet for
> supplies, but if I buy new 62.5/125um 4-strand cable with SC connectors
> and a pull ring, it'll cost over $500 for just the cable to go 400 feet.
>
> It's more of a mental block, I guess, than anything else. I was hoping
> for a solution in a box, but when I look at rigging it up myself, then
> suddenly I cannot see the advantage of just running a short optical
> jumper -- I seem to lean to making the whole link out of fiber, and doing
> away with the copper entirely.
>
> Oh, well... I do NOT want to have to replace the components every time we
> get a strike on the lines down our road. We pretty much have had to do
> that in the past (when on dial-up). Just like the high-speed link will
> be, our phones are common to both buildings, even though the power is on
> separate transformers; and every time one building took a hit, both ends
> got fried.

lightning protection is not just about the convertor....

note every convertor i have seen uses a power feed, so your isolation scheme
has a couple of holes in it - a strike at either end will cause a spike on
the ground voltage as the strike dissipates to earth.

i have also had RS422 equipment with part of the card vaporised rather than
just not working when there was a strike on a road - our expensive shielded
cable ran a couple of meters away and 1 m down........
>
> So I suppose I'll suck it up and go the optical/media converter route.
> (yet another $700 out of the construction budget)

golden rule for telecomms is that the expensive bit is digging the hole -
put down multiple tubes so you have some future options (rule of thumb used
to be £100 / m for public roads - on a private site things should be
easier).

and since the fibre is inherently safe you can run a power cable down
another tube in the same hole in the ground (or even the same one, but big
cables tend to break small cables in the same duct when you pull them in)
>
> LLoyd
--
Regards

(E-Mail Removed) - replace xyz with ntl

On Feb 8, 11:40 am, "Lloyd E. Sponenburgh"
<lloydspinsidemindspring.com> wrote:
>>> Oh, well... I do NOT want to have to replace the components every time
> >> we get a strike on the lines down our road. ...
>> That's likely to happen in any event unless you install serious
>>lightningprotection.
> ,,, The considerations for _guaranteed_ thrice-annual
> strikes on incoming service are costly, but do-able.

First, routine to have direct strikes and no damage. Your telco
connects its $multi-million computer to buildings, via overhead wires,
all over town. Every thunderstorm typically creates maybe 100 surges
- without damage. If every wire is earthed where entering the
building, then lightning need not seek earth ground, destructively,
via interior electronics.

Same solution was installed in FL's Orange County Emergency Response
facilities. Protectors and isolation were not a solution:
http://www.psihq.com/AllCopper.htm

A first building may act as a lightning rod to find earth ground,
destructively, via electronics in the second building. Solution was
discussed recently. This problem and a simple, inexpensive solution
that was standard even 100 years ago is in "Long cat5 run question" in
alt.internet.wireless on 24 Jan 2008 at:
http://tinyurl.com/2h69ho

Second, any protector destroyed by a surge was not providing
protection. But failure (by being grossly undersized) gets myths to
promote those effective and grossly overpriced solutions. The
standard protection system means a direct lightning strike and
resulting surge is not even known. Properly earthed protection is that
routine and effective that nobody knows when it happens. Earthing
defines quality of any surge protection 'system'; including essential
short (low impedance) connections from each wire to a single point
earth ground.

Third, a least expensive solution is also most effective. Only one
component is always required in every surge protection system: earth
ground. That requirement applies to every incoming wire - not just a
Cat5 cable. Damage is created when a surge is permitted inside the
building - permitted to find earth ground, destructively, inside that
building. One path might be incoming on AC electric and outgoing to
earth via that Cat 5 wire. Do not assume damage on a Cat 5 cable is
due to a surge entering on Cat 5 wires. A surge could also be
incoming on AC mains and outgoing to earth ground, destructively, via
Cat 5 wires.