external cat5 run to router..

Eurorunner

I have blown two eircom wireless routers in the space of 2 months - due to lightening. Theres a long external network cable run from router in office to house. I think this is the problem. Lightening hits it - and runs back into router , blowing the wired LAN sockets only (wireless still works - as it did with the previous router).
Plugging it out when theres thunder/lightening is an obvious preventative step - but not a practical one.
Is there anything else I can do? Anything that can be installed between cable run and router lan socket - to stop the lightening surge?
Anyone else here with similar setup having same problem?

lambchops

Well I'd start by figuring out why your cat cable keeps getting hit by lightning.

Do you have it running over anything metal that might attract lightning?

watty

A hit within 100m ANYWHERE between exchange and ADSL modem may fry it.

Cat5e really hit by lightning? You'd see about 1m of cable vanish and also all the equipment at either end would be damaged.

Any exposed cable not special ducts etc, is always better being STP, shielded Twisted pair. The screen wire is only earthed at one end (usually a patch panel, or else use metal earthing shell on one end of cable only, but the socket on router must be then earthed.

NOTHING, not even telecom surge protectors can survive a direct hit.

You can simply get a static discharge when there is a storm. No physical damage as with a real strike. The "earthed at one end" screened Cat5e will protect for that if an earthed patch panel is used at one end.

Eurorunner

lambchops wrote: »

Well I'd start by figuring out why your cat cable keeps getting hit by lightning.

Do you have it running over anything metal that might attract lightning?

Not that I can recall - will have to double check when I get back. I know its close to metal - but not in contact with it.

watty wrote:

Any exposed cable not special ducts etc, is always better being STP, shielded Twisted pair. The screen wire is only earthed at one end (usually a patch panel, or else use metal earthing shell on one end of cable only, but the socket on router must be then earthed.

I think its UTP from what I can make out here.
Theres no patch panel involved. its just a straight cable with booted ends - one end in LAN port of modem ...the other going into a Netgear Powerline ethernet plug - for distribution within the house. This is usually plugged out at night.

Watty wrote:

A hit within 100m ANYWHERE between exchange and ADSL modem may fry it.....Cat5e really hit by lightning? You'd see about 1m of cable vanish and also all the equipment at either end would be damaged.

If its the phone line, would it just blow the LAN ports and leave wireless working? Would it not blow the lot?
If a direct hit would literally fry the cable, can I be secure in the knowledge that the cable isn't the culprit in this case?

watty

The problem is UTP. (UNSHIELDED). It's more likely static discharge during a storm, especially since the phoneline/WiFi part still works. UTP is no protection, STP is lots.

Definitely not a strike on your CAT5, you would see scorch marks too. A direct strike damage is awesome to see.

* Unearthed mast on a concrete equipment building: All the concrete blew off the the steel reinforcing.

* Strike on TV aerial: EVERY piece of electrical/electronic wrecked. Many sockets / connections explode.

* Direct strike on phone line: Fax a burnt mess. Nearby strikes (anywhere along phone line) simply kill Modems, routers, faxes, motherboards with internal modems, serial ports connected to analog modem etc...

Some examples
http://www.donan.com/services/engineering-investigations/low-high-voltage
http://commons.wikimedia.org/wiki/Image:Lightning_damage_2.JPG
http://www.enertecservices.co.nz/damage.html

Example of not so close strike:
http://picasaweb.google.com/brockjk/Lightning_Weather/photo#5210554358841554738

Strike near a satellite Dish:
http://dalecrow.com/hit.htm

Read about what happens to fittings:
http://www.bbc.co.uk/devon/news/122000/13/floods_1312.shtml

Satellite dishes are insulated from LNB/coax wiring to aviod storm or strong wind + dust static damage. A dish should be earthed to a ground spike if on a mobile home, caravan, shed, timberframe or other surface not "earthy".

The screen on STP Cat5e (earth only one end) stops a static charge building up and shields the signal pins on ethernet socket from interference spikes or RF noise or local transmitters.

paulm17781

Could it be the netgear powerline plug? Sounds like a candidate to me.

Eurorunner

watty wrote: »

The problem is UTP. (UNSHIELDED). It's more likely static discharge during a storm, especially since the phoneline/WiFi part still works. UTP is no protection, STP is lots.

Thanks for the detailed post Watty.
So the bottom line is that the utp needs to be swapped out with stp? Am I right in saying thats utp cable in the link in my previous post (it doesnt actually say in the description but there is a reference to some standard or other)?
I suppose I'm holding out in the hope theres a workaround - as replacing involves a world of pain.
I've had this setup since January - only problem was two months ago and now.

paulm17781 wrote:

Could it be the netgear powerline plug?

Have been using the exact same make/model powerline plugs in my own house for the last 12 months - connected to a (BT 2110) router - without any problems. Only thing that would be different with this setup is the long cable run leading into it...unless that makes a difference?...

watty

Long cables are more prone to pick up noise and static. I always use STP for exposed cables.

Peel back part of outer insulation anywhere.

UTP is just the four pairs of wire.

STP has an aluminium wrapper around the pairs and a bare drain wire as the foil may crack and go "open circuit".

Eurorunner

watty wrote: »

Long cables are more prone to pick up noise and static. I always use STP for exposed cables.

Peel back part of outer insulation anywhere.

UTP is just the four pairs of wire.

STP has an aluminium wrapper around the pairs and a bare drain wire as the foil may crack and go "open circuit".

I contacted the vendor and he confirmed its definitely utp.

Is there any reason why it only hits the router - should it not have an equal chance of bodging the powerline plug? Will have to check but it could be a case that powerline plug was in 24/7 for the first few months but is often disconnected from cable since this problem first occured. Is that likely to have any bearing on things?

paulm17781

Maybe the plug has gone faulty? I've never really looked at them but I don't trust it (ethernet over power) on principle. It seems strange to me that the ethernet ports, connected to this plug, are what is faulty. As Watty said, lightening seems unlikely but something connected to that router is causing it to blow. I'd really consider changing method / trying a new plug.

Eurorunner

paulm17781 wrote: »

I'd really consider changing method / trying a new plug.

Have a couple spare at the moment - never used - so once eircom replace router, I'll swap the plug out and wait and see if disaster strikes a third time.

DECEiFER

I wonder if a Surge Protector work on your AC line?

watty

No. Consumer surge protectors are fairly useless.

It's not impossible that it's the homeplug, but very unlikely, more likely due to exposed unscreened long run of cable.