Lightning strike & fibre

[bluesofa]

Straight question, not about a lightning strike down the fibre itself, but does anyone know, talking about FTTH, if the fibre coming into the house from the pole has a metal shrouding?

I haven’t been able see to on my installation (AIS Fibre) if it has a protective metal outer shrouding. Obviously I’d hope not.

Maybe it has something else non-conductive around it for strength/protection?

[Crossy]

We have TOT FTTH, the incoming fibre does not appear to have either a metallic sheath nor a carrier wire.

Also, there is a mux unit in a plastic box near where the fibre enters the house, the fibre coming out to the router definitely has nothing metallic associated with it.

On the whole it's going to be pretty bomb proof as far as lightning induced nasties are concerned.

[bluesofa]

Thanks for the reply. I won't bother disconnecting my internet right now (got some ongoing thunder in my area).

Still on lightning, when I was searching TV for this subject, I came across a post from a couple of years back about coax into the house (we have cable TV) I noticed someone posted a link to this: http://www.l-com.com/surge-protector-f-female-to-f-female-0-3-ghz-90v-lightning-protector A 3Ghz lightning protector, this decent one has an earth connexion.

I've seen various others (also described as "lightning surge protectors") which just have two F plugs in-out and nothing else. What on earth is the use of that if it has nowhere to discharge to?

[KhunBENQ]

Just looked up the cable spec that was installed at our house:

From the type spec. I googled around and found it to be a "self supporting fibre cable".

There is an "FRP" FIBRE REINFORCED PLASTIC ROD.

And obviously NO metallic wires/strings or the like.

With that I assume that it is highly unlikely that this cable will carry lightning surges.

Previously I had ADSL (copper) which was grounded through some box at the wall.

No such thing for the fibre cable. From the pole to the house.

BTW: the weight of the cable is 28 kg / km.

28 grams (!) per meter.

Does someone know what an ADSL copper cable would weigh?

Edited May 16, 2016 by KhunBENQ

[IMA_FARANG]

Just for your info.....I once worked in a communications site in Saudi Arabia

We had a reciever site with a Grounding system (Earthing to you Brits).

Main ground was next to a large boulder.

During a thuderstorm ( yes they do have thunderstorms ocassionally in Saudi Arabia) a bolt of lightning struck that boulder.

The mark of the lightning bolt was clearly shone on the boulder.

We lost two recievers, one on-line and the on-line backup reciever.

About the last meter of "grounding cable" was burned up from that bolt of loghtning....which never actually strck the Ground cable....only the boulder nearby.

[AlQaholic]

Just looked up the cable spec that was installed at our house:

140317175654.jpg

From the type spec. I googled around and found it to be a "self supporting fibre cable".

There is an "FRP" FIBRE REINFORCED PLASTIC ROD.

And obviously NO metallic wires/strings or the like.

fibre_FTTH.jpg

With that I assume that it is highly unlikely that this cable will carry lightning surges.

Previously I had ADSL (copper) which was grounded through some box at the wall.

No such thing for the fibre cable. From the pole to the house.

BTW: the weight of the cable is 28 kg / km.

28 grams (!) per meter.

Does someone know what an ADSL copper cable would weigh?

What your showing is a multi core cable for subsea installation.

[bluesofa]

Ah, when I looked at the drawing I wondered why it was multi-strand, too. I missed the obvious about what else it might be.

I googled the spec quoted and it appears to come from China: http://www.sgtaobao.com/product/3172530951/

Looks like this particular one does have a carrier wire attached, so it might be prone to a lightning strike?

Edited May 17, 2016 by bluesofa

[Crocbait]

My True Fibre definitely has a metal carrier wire attached like the photo from Bluesofa.

[bluesofa]

I've just done an inspection of my AIS Fibre installation. I can now see I too have a carrier wire with the fibre cable.which goes into the ceiling space at one side of the house. Where it drops down to the terminal adaptor, it's a much lighter fibre optical cable. AIS must have terminated it somewhere in the loft-space, but as yet I don't know where.

I still have a TOT analogue line coming in with a carrier wire, but at least that goes to an NTP on the wall outside the house. Then into the house on some internal 4-wire and also a TOT-provided earth to the NTP too, which is great.

[al007]

I used to laugh at the locals disconnecting all electrical in thunderstorms

I have lost two 42 in tv , cctv, two routers,Hard drive, apple TV plus a lot more ( I was lucky some still under warranty!)

I have five control panels all with ground earthing switches, last week end they all blew, and my expensive router also lost

SO IN FUTURE WILL DISCONECT and follow the locals, problem is in the bigstorms the static in the air can also do damage

ALSO NEED TO BUY FIRE EXTINGUISHERS FOR HOUSE IN LAST STORM FLASHING AROUNE THE PLACE

[Rockhopper]

I was a sales consultant and sold fiber optic cables from Belden. Some earlier fiber cables did use aluminum tape.

http://www.beldensolutions.com/res/Media/beldensolutions.com/Media/Bilder/Data_Center/PDF/FiberExpressCatalog.pdf/FiberExpressCatalog.pdf.pdf

http://www.beldencables-emea.com/en/products/fiber-optics-20111019/index.phtml

[Crossy]

All interesting stuff.

I don't have a spec. for our incoming line but it appears to have a non-metallic carrier, maybe TOT are more scared than the others of lightning.

To be honest, even with a metallic carrier it would take a direct hit on the fibre to generate anything worth worrying about, and the lightning will like the earthed protection wire on top of the poles followed by the HV then LV wires before it gets anywhere near the fibre.

+1 On the fire extinguisher al007, first thing (three) we bought when we moved in to our house.

[Richard-BKK]

A friend had once had a lightning and the fiber-cable needed to replaced... (not much was left anyway).

Our fiber cables also have a metal protection wire, which I use as antenna... the cable to my house is just under 1000 meters so I have a very big antenna...