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Ethernet and power surges (thunderstorms)
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Daniel James
Sep 25, 2016, 7:02:20 AM9/25/16
to
For ease of cabling, we have a length of Cat5e cable that runs around
the *outside* of part of the house. There's a wall box at each end, one
of which is connected by a patch cable to the ADSL router, the other to
an ethernet switch. The cable is just a length of Cat5e run through
holes in the brickwork and stapled to the wall of the house by a
helpful local builder.
In the recent storms that cable seems to have picked up a charge that
damaged the ADSL router and possibly also the switch, but (fortunately)
nothing else.
The ethernet port on the router that was connected to the external
cable is dead (the others are fine) and the ADSL connection is dead,
though the router itself and the built-in WiFi are still working.
There was no lightning strike, but the storm was directly overhead and
very active. I can well imagine that it might have induced a sufficient
current in the external cable to damage the connected kit.
What can I do to reduce the likelihood of this happening again? Should
I install metal sheathing around the external cable? I see that one can
purchase ethernet surge protector devices, are these any good?
What does the team think?
--
Cheers,
Daniel.
the *outside* of part of the house. There's a wall box at each end, one
of which is connected by a patch cable to the ADSL router, the other to
an ethernet switch. The cable is just a length of Cat5e run through
holes in the brickwork and stapled to the wall of the house by a
helpful local builder.
In the recent storms that cable seems to have picked up a charge that
damaged the ADSL router and possibly also the switch, but (fortunately)
nothing else.
The ethernet port on the router that was connected to the external
cable is dead (the others are fine) and the ADSL connection is dead,
though the router itself and the built-in WiFi are still working.
There was no lightning strike, but the storm was directly overhead and
very active. I can well imagine that it might have induced a sufficient
current in the external cable to damage the connected kit.
What can I do to reduce the likelihood of this happening again? Should
I install metal sheathing around the external cable? I see that one can
purchase ethernet surge protector devices, are these any good?
What does the team think?
--
Cheers,
Daniel.
Adrian Caspersz
Sep 26, 2016, 7:13:01 AM9/26/16
to
Does any of your switching kit take mini-GBIC transceiver modules? Cheap
on eBay. I paid £5 for a couple once on eBay and have laid fibre outside
mindful of the same issues with lightning.
--
Adrian C
Daniel James
Sep 26, 2016, 8:15:30 AM9/26/16
to
In article <e4se5s...@mid.individual.net>, Adrian Caspersz wrote:
> Go fibre?
That's an interesting idea -- would certainly address the issue of
susceptibility to lightning, etc. -- but I'm not sure I'd know how.
> Does any of your switching kit take mini-GBIC transceiver modules?
Nope (I had to look up mini-GBIC). So-called RJ-45 sockets only. The
router is a Draytek Vigor2860ac (the one clobbered by the lightning was
a 2860n, but I took the opportunity to upgrade as we have some 5GHz
devices around the place) and the switch is bog standard Netgear
100Mbps thing.
Sounds like significant expenditure would be required to add fibre
capability here?
--
Cheers,
Daniel.
> Go fibre?
That's an interesting idea -- would certainly address the issue of
susceptibility to lightning, etc. -- but I'm not sure I'd know how.
> Does any of your switching kit take mini-GBIC transceiver modules?
router is a Draytek Vigor2860ac (the one clobbered by the lightning was
a 2860n, but I took the opportunity to upgrade as we have some 5GHz
devices around the place) and the switch is bog standard Netgear
100Mbps thing.
Sounds like significant expenditure would be required to add fibre
capability here?
--
Cheers,
Daniel.
Adrian Caspersz
Sep 26, 2016, 1:07:39 PM9/26/16
to
For work, I've a couple of cheapish managed switches with mini-GBIC, a
24-port fanless gigabit TP-Link TL-SG2424 and an old noisy Linksys
SRW208P which lives next to an even noisier server.
The TP-Link was about £100 new and the linksys was scored from a car
boot sale for peanuts, is 10/100 and gigabit for a couple of ports.
A length of OM1 fibre with premade LC-LC connectors was about £20.
--
Adrian C
Stephen
Sep 26, 2016, 3:51:09 PM9/26/16
to
On Sun, 25 Sep 2016 12:02:19 +0100, Daniel James <dan...@me.invalid>
wrote:
>For ease of cabling, we have a length of Cat5e cable that runs around
>the *outside* of part of the house. There's a wall box at each end, one
>of which is connected by a patch cable to the ADSL router, the other to
>an ethernet switch. The cable is just a length of Cat5e run through
>holes in the brickwork and stapled to the wall of the house by a
>helpful local builder.
>
>In the recent storms that cable seems to have picked up a charge that
>damaged the ADSL router and possibly also the switch, but (fortunately)
>nothing else.
You were lucky - the energy involved in an actual strike is sufficient
to vaporise the cable.....
I have seen some of the electronics on a device taking a "near miss"
to be vaporised on the circuit board.
have a look at the various lightning protection codes.
http://lightningsafety.com/nlsi_lhm/IEEE_Guide.pdf
>
>The ethernet port on the router that was connected to the external
>cable is dead (the others are fine) and the ADSL connection is dead,
>though the router itself and the built-in WiFi are still working.
>
>There was no lightning strike, but the storm was directly overhead and
>very active. I can well imagine that it might have induced a sufficient
>current in the external cable to damage the connected kit.
A nearby strike will involve a heavy current through to "ground" which
can make for a large change in the ground voltage - this is 1 reason
it isnt a good idea to shelter under a tree in a lightning storm.
The effect reduces rapidly as you get further from the strike.
if devices are grounded at different places with 1 closer to a "close"
strike, the resulting current flow can cause damage.
You can get related spikes coming in through external cable, power or
phone lines
to limit interference and that will help.
I suspect non metallic protected fibre is the ideal way to go since
this is how building to building LAN cabling is done by default.
it wont shield the devices at each end from power line surges, but at
least they will not have a ground spike on 1 but not the other causing
a current through the connecting cable.
If you want to shield a metal cable then the shield needs to be set up
such that it doesnt just channel induced current into the cable and
cause damage that way.
Maybe accepting the risk and the occasional device replacement will be
cheapest.
Stephen Hope stephe...@xyzworld.com
Replace xyz with ntl to reply
wrote:
>For ease of cabling, we have a length of Cat5e cable that runs around
>the *outside* of part of the house. There's a wall box at each end, one
>of which is connected by a patch cable to the ADSL router, the other to
>an ethernet switch. The cable is just a length of Cat5e run through
>holes in the brickwork and stapled to the wall of the house by a
>helpful local builder.
>
>In the recent storms that cable seems to have picked up a charge that
>damaged the ADSL router and possibly also the switch, but (fortunately)
>nothing else.
to vaporise the cable.....
I have seen some of the electronics on a device taking a "near miss"
to be vaporised on the circuit board.
have a look at the various lightning protection codes.
http://lightningsafety.com/nlsi_lhm/IEEE_Guide.pdf
>
>The ethernet port on the router that was connected to the external
>cable is dead (the others are fine) and the ADSL connection is dead,
>though the router itself and the built-in WiFi are still working.
>
>There was no lightning strike, but the storm was directly overhead and
>very active. I can well imagine that it might have induced a sufficient
>current in the external cable to damage the connected kit.
can make for a large change in the ground voltage - this is 1 reason
it isnt a good idea to shelter under a tree in a lightning storm.
The effect reduces rapidly as you get further from the strike.
if devices are grounded at different places with 1 closer to a "close"
strike, the resulting current flow can cause damage.
You can get related spikes coming in through external cable, power or
phone lines
>
>What can I do to reduce the likelihood of this happening again? Should
>I install metal sheathing around the external cable? I see that one can
>purchase ethernet surge protector devices, are these any good?
>
>What does the team think?
Ethernet already has twisted pairs & insulated transformers included
>What can I do to reduce the likelihood of this happening again? Should
>I install metal sheathing around the external cable? I see that one can
>purchase ethernet surge protector devices, are these any good?
>
>What does the team think?
to limit interference and that will help.
I suspect non metallic protected fibre is the ideal way to go since
this is how building to building LAN cabling is done by default.
it wont shield the devices at each end from power line surges, but at
least they will not have a ground spike on 1 but not the other causing
a current through the connecting cable.
If you want to shield a metal cable then the shield needs to be set up
such that it doesnt just channel induced current into the cable and
cause damage that way.
Maybe accepting the risk and the occasional device replacement will be
cheapest.
Stephen Hope stephe...@xyzworld.com
Replace xyz with ntl to reply
gargoyle60
Sep 27, 2016, 5:45:20 AM9/27/16
to
On Mon, 26 Sep 2016 20:51:07 +0100, Stephen <stephe...@xyzworld.com> wrote:
>I have seen some of the electronics on a device taking a "near miss"
>to be vaporised on the circuit board.
Years ago a nearby lightning strike knocked out my old dial-up modem along with those of all my
>I have seen some of the electronics on a device taking a "near miss"
>to be vaporised on the circuit board.
neighbours, even though the stike didn't hit any telephone poles.
Daniel James
Sep 27, 2016, 8:45:27 AM9/27/16
to
In article <ustiub5japj3m9f7f...@4ax.com>, Stephen wrote:
> You were lucky - the energy involved in an actual strike is sufficient
> to vaporise the cable.....
Unlucky to be affected at all ... lucky it wasn't worse. <shrug>
> You were lucky - the energy involved in an actual strike is sufficient
> to vaporise the cable.....
> A nearby strike will involve a heavy current through to "ground" which
> can make for a large change in the ground voltage - this is 1 reason
> it isnt a good idea to shelter under a tree in a lightning storm.
advice on how to minimize the damage the impact of this happening again.
> If you want to shield a metal cable then the shield needs to be set up
> such that it doesnt just channel induced current into the cable and
> cause damage that way.
conduit of some sort would very likely make the conduit itself act like
a lightning conductor, and increase the risk to the equipment.
Mind you, there's more chance of loss from a strike on the TV aerial on
the roof blowing up the set in the living room (which didn't happen).
> Maybe accepting the risk and the occasional device replacement will be
> cheapest.
--
Cheers,
Daniel.
Andrew Gabriel
Nov 21, 2016, 1:30:37 PM11/21/16
to
In article <VA.00000bd...@me.invalid>,
I would not discount the possibility the pulse came in on the phone
line. 5-10km line to the exchange is probably 1000x more likely to
pick up a spike than 10m of wire around your house.
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
line. 5-10km line to the exchange is probably 1000x more likely to
pick up a spike than 10m of wire around your house.
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
Daniel James
Nov 21, 2016, 6:55:27 PM11/21/16
to
In article <o0vef9$tgq$1...@dont-email.me>, Andrew Gabriel wrote:
> I would not discount the possibility the pulse came in on the phone
> line. 5-10km line to the exchange is probably 1000x more likely to
> pick up a spike than 10m of wire around your house.
It's true that the damaged parts are all in the path between the phone
> I would not discount the possibility the pulse came in on the phone
> line. 5-10km line to the exchange is probably 1000x more likely to
> pick up a spike than 10m of wire around your house.
line and the external ethernet cable, but there is a surge protector
between the phone socket and the router and that *should* have blown
before the equipment itself.
That's one of the things that prompted me to look into surge protectors
for ethernet before I started this thread.
--
Cheers,
Daniel.
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