Fibre cable type/construction of Openreach FTTP aerial cable

Just out of interest, the black overhead stuff with the yellow stripe....

Can any Openreach insiders tell us what the construction of the cable is? Is it a 'loose tube' construction or is it 'tight buffered' - taking me back to my structured cabling days yonks ago.

I would be shocked if it was SWA style...

Anyone know - a fellow is asking what possible damage stray lead shot could do to the cable. Apparently they have had issues in the past with overhead copper cabling being damaged in such a way, I guess from a poor shot on the local shoot! (or someone with an axe to grind against BT).

Yellow stripe usually means blown fibre tube (often around 1 inch diameter)

If blown fibre, lead shot might just puncture outer or inner tube and miss the fibre, but it will break the fibre if it makes contact and mean a new fibre needs blowing.

If its the connectorised fibre, then the kevlar reinforcement while adding strength will most likely not stop lead shot due to its main of adding strength for push/pull rather than armour

Except that it isn�t usually �stray lead shot� ....

Someone spots a bird perched on an aerial cable and fires directly at it .... bingo, [censored] cable.

Poor Busby

Actually, at 25-40m away, the chance of a pellet hitting full on is pretty minimal. The pattern will be 1 to 1.5 m diameter so very wide spread.

Is the lateral spread the same as the vertical? Somehow my "standard read" of your post was initially taken by my brain as referring only to vertical.

i.e. at right-angles to the target.


Presumably the shot cluster randomly around the mean in a roughly circular overall manner. The wire will of course not be generally horizontal or straight, giving rise to some quite interesting maths .

Oh, and! Assuming the pheasant attempts to take off on hearing the gun fire, the wire will be vibrating two-dimensionally.

Edited by RobertoS (Fri 17-May-19 01:18:24)

Roughly - yes. Shot spreads laterally and vertically by about the same amount and whilst the outer diameter is much the same for a specific cartridge, choke and gun it does vary for differing combinations. Cluster is not a word I would use - they are wide speread over maaybe 2 sq metres. The also spead in a third plane - along teh axis of fire, with some moving away faster and others getting left behind and that could be anywhere from 1 to 5 metres.

And as there are anywhere from 200-300 individual pellets of around 2.5mm diameter in most popular cartridges the total cross sectional area of those is very small in comparison.

In reply to a post by RobertoS:

Oh, and! Assuming the pheasant attempts to take off on hearing the gun fire, the wire will be vibrating two-dimensionally.

Don't recall ever seeing a pheasant on a wire, pigeons and squirels however frequently use them, and I did point out to someone I know that it probably wasn't a good idea to try and shoot squirels off the wire.

In reply to a post by burble:

In reply to a post by RobertoS:

Oh, and! Assuming the pheasant attempts to take off on hearing the gun fire, the wire will be vibrating two-dimensionally.

Don't recall ever seeing a pheasant on a wire, pigeons and squirels however frequently use them, and I did point out to someone I know that it probably wasn't a good idea to try and shoot squirels off the wire.

I have my doubts on that as well. Pheasants can't balance well enough!

The "pheasant" reference was a brain-slip caused by the OP's nick . Sorry about that.

Any bird that can sit on wire will do, but in this case although copper wires are mentioned in the final paragraph the opening was about a rather more substantial orange-striped affair.

A pheasant might be able to grip that, and do so safe in the knowledge that nobody would shoot at it on such important infrastructure.

Oh! Wait!
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We are talking about people who shoot birds for fun. Maybe the pheasant on the wire over-rates the humans involved.

Edited by RobertoS (Fri 17-May-19 14:00:33)