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Ethernet cable advice for observatory

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33 replies to this topic

#26 wboeck

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Posted 12 September 2021 - 05:31 PM

I am getting fiber and not worry about cat6 being too close in the trench to electrical and the potential of lightning. What is the best way to pull the fiber? The fiber doesn't have a pulling eye so I probably need one. Also, what is the best way to enter connect to the exterior of houses? I am thinking about drilling a hole in my siding and using a pvc J box and run the cable under the floor joists to a media converter and router. The J box should help wit pulling the fiber?


Edited by wboeck, 12 September 2021 - 07:40 PM.


#27 csandfort

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Posted 13 September 2021 - 10:37 AM

 Also, what is the best way to enter connect to the exterior of houses? I am thinking about drilling a hole in my siding and using a pvc J box and run the cable under the floor joists to a media converter and router. The J box should help wit pulling the fiber?

One way to get into the house is a Smart LB. It's designed with no sharp edges and has a radius so the fiber cable does not kink.



#28 wboeck

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Posted 13 September 2021 - 05:00 PM

One way to get into the house is a Smart LB. It's designed with no sharp edges and has a radius so the fiber cable does not kink.

I am using 1" pvc conduit for fiber. I can not find any smart LB for that size. I see a 1.25" pvc and aluminum but seems expensive. 



#29 csandfort

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Posted 13 September 2021 - 05:42 PM

The $60 bucks for the smart LB is more expensive than a J box but it could be considered one of the right tools for the job. A 1" to 1 1/4" coupler near the end of your conduit or a 1" to 1 1/4" bushing at the LB takes care of the size difference.

 

As I said, it's one way to get into the house.



#30 Christopher Erickson

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Posted 14 September 2021 - 03:04 PM

All it takes is one tiny gap in the PVC glue in one junction to fill a plastic conduit with water. And it happens WAY TOO OFTEN to be ignored. Theory meets practice.

 

 

If by "Plastic conduit" you mean PVC, electrical or otherwise, your inspector is nuts.  Over the years I have laid miles of PVC, both water and electric.  If done correctly, which a 6 year old could do with 30 seconds instruction, they will not leak.  Old school threaded pipe or metal conduit  is a different story.

 

And if water does get in, it would have to be condensation, not a leak.



#31 Christopher Erickson

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Posted 14 September 2021 - 03:09 PM

It all depends on what fiber you buy. Fiber comes with all kinds of different cladding, jackets and armor. Some are designed for being pulled into conduits. Some are designed for direct burial. And some are designed for indoor use in ducting or trays. Some are designed for laying on the ground in tough environments. I often use "Tactical" fiber pairs/bundles in the big observatories.

 

I am getting fiber and not worry about cat6 being too close in the trench to electrical and the potential of lightning. What is the best way to pull the fiber? The fiber doesn't have a pulling eye so I probably need one. Also, what is the best way to enter connect to the exterior of houses? I am thinking about drilling a hole in my siding and using a pvc J box and run the cable under the floor joists to a media converter and router. The J box should help wit pulling the fiber?



#32 TheSheriff

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Posted 15 September 2021 - 03:39 AM

All it takes is one tiny gap in the PVC glue in one junction to fill a plastic conduit with water. And it happens WAY TOO OFTEN to be ignored. Theory meets practice.

I stand by what I wrote.

 

If one can't, or are not sure if you can properly glue PVC pipe without, "One tiny gap" , it is probably best not to try.

 

The opposite of this application would be a PVC pressure water line.  If you, "Way to often" have a tiny gap which results in a pressure leak in your now buried line, you would not be in business for long.   I have never, ever had a glued connection leak.  Other issues yes, but not a glued joint.

 

I don't doubt your experiences, but your message seems overly ominous for a new DIY'er.  If one can't take a few minutes to research and perform this very simple skill, I would recommend hiring someone who can.



#33 Christopher Erickson

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Posted 15 September 2021 - 03:51 AM

Of all the times I have been brought out to either troubleshoot or upgrade comms in ground conduits, more than half the time there has been water in them. Maybe leaks, maybe condensation, maybe wicking, maybe intrusion at the ends.



#34 Brent Campbell

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Posted 15 September 2021 - 04:00 AM

I am not completely against fiber. It appears that the conduit needs special bends and equipment on each side of the fiber. Would it work in regular 90 degree electrical pvc conduit going up into my concrete pedestal and in a J box for connecting to the side of the house? Is 2 inch conduit a must with fiber?

 

thanks,

Wayne

You can’t do 90 degree bends. Think arcs.  Even cat 5 or 6 cable shouldn’t do 90 degree bends.  Fiber will fit in 1/2 inch conduet easily.  The reason you want larger conduet is that it is easier to pull cable through it and it allows for future expansion.  This may not be possible on your pier.  The  most standard way to do this is go fiber to a switch in your observatory and then cat 6 to everything else including your telescope pier.  The eliminates Electrical interference between buildings, gets rid of the possibility of your grounds not being the same on both buildings, and makes expansion easier.

 

the post where the author said to use the smallest possible conduet and thread it through is just plain silly.  The purpose of conduet is to protect the cable and allow for servicing or replacing the cable in the future.  
 

once the conduet has been run connect one side to show vac and wad up some tissues with a string.  It will pull the string right through your conduet.    Every time you pull a new cable pull a new pull string with it.




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