Fiber optic?

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NE (9.06 miles @5.9 Degrees from Winged Horses)
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EC - retired
Customer called today about a damage by lightning to their building network system. The buildings are stretched on the property. They don’t know which building was closest to either strike but they sustained considerable damage in both buildings. I suggested they use fiber between the buildings for both phone and LAN. Would that help? Those are the only metallic paths between the buildings. IDR if the same primary feeds both transformer banks.
 
I suggested they use fiber between the buildings for both phone and LAN. Would that help?

Very much. If they did have copper telecom, there should have had proper protectors at each end but those will only go so far.

At this point, I'd never run new copper telecom between buildings. And given the way prices have gone, I wouldn't run multi-mode fiber, either; single-mode is getting cheaper all the time and it can run faster/farther. (Oh, and never run fewer than six strands anywhere. Maybe don't terminate all of them, but then you'll have some extra capacity at little extra cost.)
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
Very much. If they did have copper telecom, there should have had proper protectors at each end but those will only go so far.

At this point, I'd never run new copper telecom between buildings.

Unless they have an IP phone system, copper is the only way to do it.

Sounds to me like the OP's IT guy should be fired. I cringe to see what that "network" looks like. Guaranteed that there were no required protectors that might have helped or that they were properly bonded.

-Hal
 

FionaZuppa

Senior Member
Location
AZ
Occupation
Part Time Electrician (semi retired, old) - EE retired.
There have been fiber-connected remote shelves for years (I DEinstalled a Mitel SX2000 cabinet over 15 years ago). Certainly most newer systems will be IP-based.

Using TCP/IP stack is not a reason for fiber.

Going digital, or needing a better layer-1 for digital is.

Using single mode vs mutli mode fiber really depends on the application of such. If multi mode serves the purpose and there is no foreseeable need for single mode, then use multi mode fiber. If the price were the same, or only a few $$ diff, then certainly use single mode.

There are many reasons why lightning will still follow PVC or HDPE (plastic) piping underground. Even with plastic the conduit itself should be bonded to the earth (ground rods) at set intervals.

But, getting a strike by lightning is low probability, so most people ignore many simple things to do for protecting stuff from lightning
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
There have been fiber-connected remote shelves for years (I DEinstalled a Mitel SX2000 cabinet over 15 years ago). Certainly most newer systems will be IP-based.

Not familiar with Mitel but, yeah they did have some pretty big systems. Apparently here though the customer doesn't even have an IP based system since the installed copper would seem to exceed the limit for ethernet. All systems are proprietary as far as connection of the system phones goes (unless they use single line T/R phones) so you won't find a way to change that over to fiber. That makes the replacement of their entire phone system part of this project.

FionaZuppa said:
There are many reasons why lightning will still follow PVC or HDPE (plastic) piping underground. Even with plastic the conduit itself should be bonded to the earth (ground rods) at set intervals.

Explain please. :?

-Hal
 

paulengr

Senior Member
With lightning and copper lines it’s a probability thing. You design the system to withstand up to a certain voltage/current. Knowing the frequency of strikes in an area and the probability distribution of strikes we can calculate the probability of damage from a strike. Insulation has a maximum voltage threshold before lightning flashes over. Surge arresters have a threshold before they intentionally conduct but a maximum current they can withstand. Even if everything is fiber the transceivers (Power/electronics) must still be protected.

As to conversion the usual practice is that there are some lines that can’t be easily converted to VoIP. In an office fax machines are a good example. In industrial plants it is never that simple. So most companies buy a bunch of IP phones and an IP PBX or gateway. Some phones have a pass thru Ethernet port so they can easily daisy chain with existing PC Ethernet wiring. This sets up the new network. The old original analog trunks or sometimes just analog lines connect to either individual voice/IP converters (ATAs) or to a larger analog gateway. Either way these connect to the new IP system. This lowers the overall system cost dramatically as the cost of internet service is much lower. Typically in a large plant a few analog lines (PRI) remain strictly as a backup for emergency purposes. Cell phones sound like a solution until the cell tower goes down. Over time as the analog components are replaced the analog converters and remaining phone lines go away.


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paulengr

Senior Member
Not familiar with Mitel but, yeah they did have some pretty big systems. Apparently here though the customer doesn't even have an IP based system since the installed copper would seem to exceed the limit for ethernet. All systems are proprietary as far as connection of the system phones goes (unless they use single line T/R phones) so you won't find a way to change that over to fiber. That makes the replacement of their entire phone system part of this project.



Explain please. :?

-Hal

Yeah so you are grounding PVC? Can I bid on your jobs?


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FionaZuppa

Senior Member
Location
AZ
Occupation
Part Time Electrician (semi retired, old) - EE retired.
1st off, plastic is a conductor, it's just a poor conductor, until you apply a few million volts. I could never understand why schools teach "inverse of conductor = insulator", make no sense. You have good and bad conductors, thats it.

2nd, the way pipes are buried can create a better opportunity for moisture to settle in that area along pipe path. This makes it easier for million+ volts to travel.

3rd, many AHJ's require tracer wire in trenches for various things. These tracers can essentially become a path for lighting, and many time they will turn into plasma, heat the surrounding moisture, and essentially explode your conduit and the stuff inside of it. I would not be surprised to learn that the scenario as described by OP has tracer wire in the trench along with the conduit.

Because you created the environment that way you should include pathways into the earth for the energy to follow. Stainless banding or clamps of the conduit and then tied to ground rod (every so many feet) will help direct the current down into the earth.
 

kwired

Electron manager
Location
NE Nebraska
1st off, plastic is a conductor, it's just a poor conductor, until you apply a few million volts. I could never understand why schools teach "inverse of conductor = insulator", make no sense. You have good and bad conductors, thats it.

2nd, the way pipes are buried can create a better opportunity for moisture to settle in that area along pipe path. This makes it easier for million+ volts to travel.

3rd, many AHJ's require tracer wire in trenches for various things. These tracers can essentially become a path for lighting, and many time they will turn into plasma, heat the surrounding moisture, and essentially explode your conduit and the stuff inside of it. I would not be surprised to learn that the scenario as described by OP has tracer wire in the trench along with the conduit.

Because you created the environment that way you should include pathways into the earth for the energy to follow. Stainless banding or clamps of the conduit and then tied to ground rod (every so many feet) will help direct the current down into the earth.

You posted what I was going to mention - tracer wires might still bring a path for lightning into the picture.
 

FionaZuppa

Senior Member
Location
AZ
Occupation
Part Time Electrician (semi retired, old) - EE retired.
I was going to say the same thing.

How about water filled conduit?

-Hal
As I noted, many reasons why........ but those volts still need to find path to that water.
Lightning would basically vaporize and explode the conduit and everything inside if it was direct or very close hit on the water.

The OP scenario sounds like stray ground voltage found a path on the copper.
 
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
As I noted, many reasons why........ but those volts still need to find path to that water.
Lightning would basically vaporize and explode the conduit and everything inside if it was direct or very close hit on the water.

The OP scenario sounds like stray ground voltage found a path on the copper.
Stray as in things blown apart, off walls and melted cables. (as described by customer)
 

FionaZuppa

Senior Member
Location
AZ
Occupation
Part Time Electrician (semi retired, old) - EE retired.
Stray as in things blown apart, off walls and melted cables. (as described by customer)

Well, we would certainly like to see what any of the conduit in the ground looks like.
Do the buildings share the same EGC from service?
 
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
Well, we would certainly like to see what any of the conduit in the ground looks like.
Do the buildings share the same EGC from service?
Building 1 is fed from a pad mount 480v wye. It has three service entrances. Two with GF protection, rods & bonded building steel for GES at each location. I installed the third & it has a ufer with steel bonded. 480 to 120/208 step downs at 5 locations, IIRC.

The office is a fed 120/240 from a pole top transformer. Ufer. No connection to building 1 other than what the tech guys did for communications and data. No common water line and they are nonmetallic.

eta: The two transformers may be fed from the same primary, if I were to hazard a guess, I’d say they are.
 
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FionaZuppa

Senior Member
Location
AZ
Occupation
Part Time Electrician (semi retired, old) - EE retired.
Building 1 is fed from a pad mount 480v wye. It has three service entrances. Two with GF protection, rods & bonded building steel for GES at each location. I installed the third & it has a ufer with steel bonded. 480 to 120/208 step downs at 5 locations, IIRC.

The office is a fed 120/240 from a pole top transformer. Ufer. No connection to building 1 other than what the tech guys did for communications and data. No common water line and they are nonmetallic.

eta: The two transformers may be fed from the same primary, if I were to hazard a guess, I’d say they are.

Ok, but the OP question was around using fiber, for a "will that help" in preventing lightning from traveling from one bldg to another? So I not sure what the power info is for?
 
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
Well, we would certainly like to see what any of the conduit in the ground looks like.
Do the buildings share the same EGC from service?

Ok, but the OP question was around using fiber, for a "will that help" in preventing lightning from traveling from one bldg to another? So I not sure what the power info is for?

To answer as fully as I can that there is no other connection of any kind between the buildings other than the cat 5 and phone lines.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
1st off, plastic is a conductor, it's just a poor conductor, until you apply a few million volts. I could never understand why schools teach "inverse of conductor = insulator", make no sense.

It does make sense. It's a one dimensional continuum with "conductor" a vector in one direction and "insulator" a vector in the other. One is the inverse of the other.
 

FionaZuppa

Senior Member
Location
AZ
Occupation
Part Time Electrician (semi retired, old) - EE retired.
It does make sense. It's a one dimensional continuum with "conductor" a vector in one direction and "insulator" a vector in the other. One is the inverse of the other.

Nah. The good conductor vector (in ohms units) is just way smaller in magnitude than the poor conductor. If physically stacked they will always add to each other, thus the vectors can never be 180o apart (true subtraction), they are in fact always 0o apart (true add).

Everything is a conductor, no escaping the physics there.

What about 2vdc across 8.98 x 1012 ohms? You still have conductance, yes?
 
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