300m outdoor Underground cable run

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olivernz

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#315634 1-Aug-2024 12:05

Hi all

Friend needs to connect two houses on same property. 300m underground. Original plan was to run fibre but finding a terminated 300m cable is posing to be a challenge. Or Cat6 with repeaters? Wifi is difficult due to vegetation.
Any ideas or new options anyone knows of? (Wellington region)
Cheers Oliver

noroad

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#3266964 1-Aug-2024 12:28

Fibrestore can custom make armored patchleads to suit

https://www.fs.com/au/products/20745.html?now_cid=220

Then use some bidirectional optics and media converters

https://www.fs.com/au/products/104626.html

https://www.fs.com/au/products/11795.html

https://www.fs.com/au/products/11802.html

lxsw20

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#3267304 1-Aug-2024 21:15

Cat6 isn't going to be a good solution here, bite the bullet and go fibre. Even if you run it and get someone in to put ends on it.

richms

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#3267433 2-Aug-2024 10:50

Find friendly chorus tech and offer cash. They have the gear and might even be able to "find" some fibre for you

Richard rich.ms

olivernz

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#3267543 2-Aug-2024 14:18

Yeah, so friend has found someone that will give him a fibre quote. Still looks like the only really viable solution. Thanks for all the answers. :-)

nztim

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#3268257 5-Aug-2024 09:08

do NOT use Cat6

Chances are that both buildings are earthed separately or even worse be on a different phase

This can lead to some nasty results; I highly recommend Fibre or PTP Wireless

If you do use CAT6 then ONLY run at the far end PoE powered devices e.g. access points

Any views expressed on these forums are my own and don't necessarily reflect those of my employer.

noroad

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#3268276 5-Aug-2024 10:15

Looks like you can even get long patchlead runs on Ali

https://www.aliexpress.com/item/1005007341899882.html?spm=a2g0o.productlist.main.5.65b7Rh5wRh5w3V&algo_pvid=f7556126-1477-4aae-bcf3-c0a4e66ae465&algo_exp_id=f7556126-1477-4aae-bcf3-c0a4e66ae465-2&pdp_npi=4%40dis%21NZD%21229.89%21114.94%21%21%21134.00%2167.00%21%40210313e917228095716848617e5eca%2112000040340777120%21sea%21NZ%211853087687%21X&curPageLogUid=475nPG4h7WQN&utparam-url=scene%3Asearch%7Cquery_from%3A

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#3268283 5-Aug-2024 10:34

noroad:

Looks like you can even get long patchlead runs on Ali

https://www.aliexpress.com/item/1005007341899882.html?spm=a2g0o.productlist.main.5.65b7Rh5wRh5w3V&algo_pvid=f7556126-1477-4aae-bcf3-c0a4e66ae465&algo_exp_id=f7556126-1477-4aae-bcf3-c0a4e66ae465-2&pdp_npi=4%40dis%21NZD%21229.89%21114.94%21%21%21134.00%2167.00%21%40210313e917228095716848617e5eca%2112000040340777120%21sea%21NZ%211853087687%21X&curPageLogUid=475nPG4h7WQN&utparam-url=scene%3Asearch%7Cquery_from%3A

Wow that is amazing. To connect two domestic LANs over one of these, what kind of device would do at each end?

noroad

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#3268287 5-Aug-2024 10:41

johno1234:

Wow that is amazing. To connect two domestic LANs over one of these, what kind of device would do at each end?

Media converters. The patchlead would be the lc-upc connector both ends. Media converters with SFP bidi pair

https://www.aliexpress.com/item/1005005003531928.html?spm=a2g0o.productlist.main.1.3810638dRR0WxW&algo_pvid=97fd0d4e-243c-4745-a547-8171de9d3208&algo_exp_id=97fd0d4e-243c-4745-a547-8171de9d3208-0&pdp_npi=4%40dis%21NZD%2133.73%2133.73%21%21%2119.66%2119.66%21%402101fb1617228111453004935e06c5%2112000031312252582%21sea%21NZ%211853087687%21X&curPageLogUid=mTnZleTcZhsz&utparam-url=scene%3Asearch%7Cquery_from%3A

Varkk

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#3268306 5-Aug-2024 11:52

A media converter will be needed at each end. Something like https://www.pbtech.co.nz/product/NETTPL0102/TP-Link-MC110CS-10100M-Media-Convert---Fiber-SC

Make sure you get the right one for the cable and connectors you use.

Or a switch or router with an appropriate fibre or SFP port

richms

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#3268321 5-Aug-2024 13:06

I would suggest using managed switches with SFP modules as that way you get some more stats out of them. Those cheap media converters all seem to have no web interface or anything to get details of the signal level or port errors from them. With a fibre connection this is important as if you get grot on the end it may link up but have terrible thruput from errors because of the weak signals.

Richard rich.ms

elpenguino

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#3268423 5-Aug-2024 19:58

nztim:

do NOT use Cat6

Chances are that both buildings are earthed separately or even worse be on a different phase

This can lead to some nasty results; I highly recommend Fibre or PTP Wireless

If you do use CAT6 then ONLY run at the far end PoE powered devices e.g. access points

Ethernet is transformer coupled. If it is inferred we are worried about different earth potentials, such a situation should not occur.

Despite galvanic isolation, such a long Ethernet run should still have transient protection added in case lightning hits the ground in the area.

When we consider these issues of isolation and transient immunity, fibre is a good choice for this job.

Most of the posters in this thread are just like chimpanzees on MDMA, full of feelings of bonhomie, joy, and optimism. Fred99 8/4/21

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richms

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#3268460 5-Aug-2024 22:57

The centre tap of ethernet transformers is often connected to the chassis thru some token capacitors or something, the transformer isolation is there for the signal and not for electrical safety. The flash over gap between the pins and the ground plane of the RJ45 jack is tiny. Nothing there will save you from a nearby strike when there is ethernet between 2 separate installations.

Richard rich.ms

elpenguino

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#3268527 6-Aug-2024 09:41

Correct, the centretap is connected via a bypass capacitor. This capacitor will dissipate noise but still provide mains isolation between the cable and the ethernet device. Remember, there's another socket with the same layout at the other end of the cable.

The transformer is there for differential signalling and isolation is a bonus. Under normal circumstances, differing ground potentials should not affect Ethernet use.

When a transient event occurs, all bets are off and protection is advised (or have a stack of spare gear ready). Combine these issues with the distance, fibre is a better option in this case.

Most of the posters in this thread are just like chimpanzees on MDMA, full of feelings of bonhomie, joy, and optimism. Fred99 8/4/21

raytaylor

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#3269983 9-Aug-2024 19:00

This is why you dont run copper ethernet between buildings.

In a storm, there are two places of concern.

1) Wind or air molecules brushing against the cable can cause static buildup which travels down the metal wires to earth. This can build up over time.

2) If there is lightning within 50kms, the ethernet cable acts as a big giant antenna and picks up the energy in much the same way a crystal radio works but at much higher power levels.

That energy travels down the wires and will arc across any standard protection / couplers at the far end.

https://www.youtube.com/watch?v=hOd8ifk0XjA

This video was filmed during a storm.

I have personally experienced at least two occasions during prolonged storms, customers have called me to their buildings where the cable to a nearby building only 30 metres away stops working for a moment every time there is thunder in the sky.

I can remember sitting at one customer site with my laptop plugged directly into the cable, and the router in the other building on the other end.
About every minute the local area connection on my laptop ethernet would suddenly show "unplugged" as it lost its sync and then a few seconds later the rumbling sound of the thunder arrives as its renegotiating. Had the source of thunder been closer thus the energy being picked up been higher, i would have killed my laptop ethernet port.

In reality we do it all the time but its rare in NZ that it is actually close enough to cause damage. Its just a calculated risk - if you run a copper line between buildings, you accept it may get damaged by a storm and static discharge or radio energy.
In telephone exchanges, they have lightning arrestors on all the customer lines so that it provides some protection for the line cards.

Ray Taylor

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