Fibre "dropwire" construction

Does Fibre Dropwire have any metallic strengthening wires within overall sheath, in the same/similar way that single-pair dropwire or two-pair dropwire has?

Just curious, since in the event of a near lightning strike, metallic strengthening wire would bring induced voltages in the house in the same way as copper dropwire with the steel strengtheners does.

Cheers!

If it’s the combined fibre/copper dropwire, then yes, it has support wires ( and of course a copper pair too, which would happily conduct the lightning )

The now preferred ‘ROC’ overhead cables are, I believe, metal free.

Thanks Zarjaz.

Cheers!

This is the Dropwires we use for Openreach PIA installations. No metal but 2 strengthening cores, one either side of the fibre.

Can be used both underground and overhead as a drop from the CBT, comes in various lengths

https://www.comtecdirect.co.uk/product/corning-roc-o...

In reply to a post by connormill:

This is the Dropwires we use for Openreach PIA installations. No metal but 2 strengthening cores, one either side of the fibre.

Can be used both underground and overhead as a drop from the CBT, comes in various lengths

https://www.comtecdirect.co.uk/product/corning-roc-o...

Out of interest can a field fit SC connector still be fitted to the end of ROC type cable?

Edit: For clarity is it possible with the different profile of the cable.

Edited by deleted (Mon 17-Jan-22 09:40:29)

Noting that a wet piece of string can look like a good conductor to a lightning strike and lightning without rain is rare in the UK.

In reply to a post by dect:

]Out of interest can a field fit SC connector still be fitted to the end of ROC type cable?

Edit: For clarity is it possible with the different profile of the cable.

Field fit connectors have been phased out in favour of the inside out cable with a factory fit connector on the end and an external splice in the csp to eliminate the many failures associated with field fit connectors.

Also to answer your question, no, they will never fit on to the flat ROC cable.

In reply to a post by TheInstaller:

to answer your question, no, they will never fit on to the flat ROC cable.

Thought so but just wanted it confirmed, many thanks

Surely you’d want to strip the black external sheath (and strength members) away before:
a) running it indoors (external grade cables are never a good call inside)
b) attempting to put any sort of field fit connector on the end. Anything larger than a 3mm OD sheath that was perfectly round would be impossible? Surely.

True, but just wondering whether I can argue that the wet roof and house would act as a Faraday cage?

I lost a DrayTek modem/router and a VoIP ATA in June 2018 during a thunderstorm. It certainly wasn't a direct hit and nothing else was damaged, which strongly suggested that a surge had come in via the telephone line which from the DP pole opposite is overhead.

Cheers!

Surges WILL come in via copper be that telecommunications or mains level power in and out. If you are in a lightning prevalent area I would suggest you invest in a proper mains surge protection on the inbound supply before it goes to your consumer unit or sub boards. Ditto any other ‘copper’ circuits should have protection, that run externally which act like giant tentacles when it comes to earth equipotential faults aka surges.

As for a building protection in the case of direct strikes, well then you’re really in the territory of lightning protection specialists looking at rods, copper straps and a network of earthing. Unless you live in a Scottish or Welsh castle it’s probably not something you’d consider.

In the UK generally the chances of repeat strikes in the same location are very low. Consequently unless there is some special reason the most sensible and cost effective form of lightning protection is insurance. That is protecting against lightning strikes will cost hundreds of times more than insurance which you should have anyway and unless it's really rubbish will cover lightning strikes anyway.

In reply to a post by jabuzzard:

In the UK generally the chances of repeat strikes in the same location are very low. Consequently unless there is some special reason the most sensible and cost effective form of lightning protection is insurance. That is protecting against lightning strikes will cost hundreds of times more than insurance which you should have anyway and unless it's really rubbish will cover lightning strikes anyway.

I still think most people tend to believe that prevention is better than cure, maybe not going into the full extremes of lighting strike prevention but maybe not running copper(ethernet) on the roof of a building or around it, is generally a good start. I know i don't run copper outside, if a connection needs to be made outside it will be fibre (unless its something minor like CCTV camera or a external access point which should be earthed anyway)

added

I would still be a bit concerned doing that, especially considering that I have had numerous lighting strikes within a 100M radius over the years, maily trees, some short some tall and all within view of my front windows.

Edited by RR_The_IT_Guy (Tue 18-Jan-22 12:21:16)

During 25 years in the Merchant Navy I never experienced a direct hit to the ships that I was on. The only lightning associated damage was one noisy night when in the morning I found the radio-telex transceiver rather quiet. A small trifilar wound ferrite toroidal transformer for receiver aerial impedance matching circuit was rather charred, due likely induced currents. Managed to find some thin insulated wire and rewound the toroid and back in business.

Normal procedure was to earth transmitting aerials when not in use, receiving aerials took their chance and anyway three of those were in use 24/7.

Cheers!

In reply to a post by jabuzzard:

In the UK generally the chances of repeat strikes in the same location are very low. Consequently unless there is some special reason the most sensible and cost effective form of lightning protection is insurance. That is protecting against lightning strikes will cost hundreds of times more than insurance which you should have anyway and unless it's really rubbish will cover lightning strikes anyway.

Maybe not where you are, but it’s pretty regular in summer where we are in East Anglia.

Having gone through it - prevention is infinitely better than arguing the toss with insurance assessors and the utter hassle of replacing gear. It took ages to replace everything (insurance monies aside). It’s something you really want to avoid if you are in a high lightning strike area - and you will know if you are.

In reply to a post by Pheasant:

In reply to a post by jabuzzard:

In the UK generally the chances of repeat strikes in the same location are very low. Consequently unless there is some special reason the most sensible and cost effective form of lightning protection is insurance. That is protecting against lightning strikes will cost hundreds of times more than insurance which you should have anyway and unless it's really rubbish will cover lightning strikes anyway.

Maybe not where you are, but it’s pretty regular in summer where we are in East Anglia.

Having gone through it - prevention is infinitely better than arguing the toss with insurance assessors and the utter hassle of replacing gear. It took ages to replace everything (insurance monies aside). It’s something you really want to avoid if you are in a high lightning strike area - and you will know if you are.

I must agree being in the region (St Neots, Cambridgeshire, Huntingdonshire) It's not happened to me yet since I try and prevent as much as possible.

How bad was it for you, did it burn all the cables and "solder" them into switches and ethernet ports?
Or did it just fry the switches and everything connected.

In reply to a post by Pheasant:

Surely you’d want to strip the black external sheath (and strength members) away before:
a) running it indoors (external grade cables are never a good call inside)
b) attempting to put any sort of field fit connector on the end. Anything larger than a 3mm OD sheath that was perfectly round would be impossible? Surely.

ROC cable is never run indoors and never has any kind of field fit connector on it.

It runs outside from the CBT to the external CSP where it is spliced on to the inside out cable, which already has a factory fitted connector on the end of it. This plugs into the ONT. Field fit connectors are no longer used due to their high failure rate.

What OH cable did OR use for CSP-less installs when they were doing them?

Tagged to last post

Has anyone come across or worked with the CommScope FHD-H01V fibre OH/UG connectorised cable used by Openreach? I came across it today and it was a lot flatter than I had expected with what looks like a single external strengthen along its length.

In reply to a post by RR_The_IT_Guy:

I would still be a bit concerned doing that, especially considering that I have had numerous lighting strikes within a 100M radius over the years, maily trees, some short some tall and all within view of my front windows.

Yes but where any of them the *same* tree? Lots of strikes in your immediate vicinity is not the same as the *same* place being stuck twice.

In reply to a post by dect:

Tagged to last post

Has anyone come across or worked with the CommScope FHD-H01V fibre OH/UG connectorised cable used by Openreach? I came across it today and it was a lot flatter than I had expected with what looks like a single external strengthen along its length.

It has 2 strengtheners in it, one at either side of the fibre. It's not all that different to the Corning ROC drop cable.

In reply to a post by troublegum:

It has 2 strengtheners in it, one at either side of the fibre. It's not all that different to the Corning ROC drop cable.

Thanks

When I looked at the specs online tonight they didn't look like what I saw today as the online specs showed a single flattish jacket with both the dielectric strengtheners and the fibre sandwiched between them but what I saw today was an extra shotgun something on one side of the main jacket which reminded me of the old copper/fibre hybrid cable so I assumed it was a strengthener as it went all the way into the connector at the CBT end which I didn't think was the case on the original copper/fibre cables.

Edit: Just found some newer specs that show it as I saw it today where one strengthener is in the main jacket and one is in the shotgun bit

Edited by deleted (Fri 28-Jan-22 22:30:07)

There no main jacket and "shotgun" bit. Both halves are the same size, it's just that the join is offset

If you look at the cable profile in the following link, you will see the groove on top is to the left. However on the underneath, the groove is to the right (diagonally opposite ).

https://www.commscope.com/globalassets/digizuite/254...

It pulls apart into 2 equal pieces if you cut it diagonally across the grooves.

In reply to a post by troublegum:

There no main jacket and "shotgun" bit. Both halves are the same size, it's just that the join is offset

If you look at the cable profile in the following link, you will see the groove on top is to the left. However on the underneath, the groove is to the right (diagonally opposite ).

https://www.commscope.com/globalassets/digizuite/254...

It pulls apart into 2 equal pieces if you cut it diagonally across the grooves.

Thanks for explaining, I only saw one side so didn't realise there was a groove diagonal on the other side.

In reply to a post by Pheasant:

What OH cable did OR use for CSP-less installs when they were doing them?

They used the hybrid fibre/copper cable. The fibre on this cable is round and could then have a field fit connector on the end of it. The current flat cables (Corning/Commscope) are fibre only cables that are totally different to the original hybrid ones.

Thanks for confirming.

In reply to a post by TheInstaller:

The current flat cables (Corning/CommScope) are fibre only

I don't know what they are like to work with but in my opinion the flattish fibre cables (CommScope 3mm x 6mm) must be less flexible than the original round fibre cables. There must be a good reason why the flattish cables are used these days.

I'm no BT (...sorry Openreach) engineer, but I'm sure I read something somewhere about superior 'noise' in certain high wind prone areas - the cable is less likely to suffer from turbulence induced hum (or something like that). Also if this is a dual OH and UG cable I believe that the flatter cables are superior to their circular brethren in ducting as they pull better and fish better...or maybe its the red wine talking and making up all this stuff

Clipping the flat fibre cable down a wall from the eaves and then looping round under a CSP can't be easy with a flat cable compared to a round cable.

Very true.

Cleating round (say) a doorframe is even harder to do neatly.

The new cables do strip MUCH easier though.

When my Community Fibre (overhead / PIA) installation was done, it used 7/3.7mm Emtelle microduct as drop cable.

A neighbour joined recently and I remember thinking that the drop cable was of much smaller diameter, around the 3mm range, perhaps with some kind of tensioner near the customer wall anchor. I'll have to see if there are any visible manufacturer markings. Assuming it meets all the relevant standards, the move to fibre is a chance to reduce the visual impact of overhead cables by using smaller diameters... but I think Openreach have stayed around the 5-6mm OD range.

They also didn't use an external CSP, which makes for a neater install on the main elevation of the house as the CF version was twice the size of the Openreach one. Rerouting mine is on the to-do list.

I wonder if this was done in the old way - connectorised cable fed outside-in, and then a field fit SC connector added internally? (No CSP)

That's how mine was done in 2019, but I believe that Openreach have moved away from that due to higher failure rate. The CSP also makes fault-finding easier without having to enter the property.

The microduct drop cable is reminiscent of the pre-connectorised Openreach FTTP, where they used to blow a 4-fibre bundle from the manifold to the CSP.

Sorry another question or 2 if I may

I noticed the CommScope cable has what looks possibly like a velcro strap near to the connector end (out of box it looked like it was rolled up and secured with a very large cable tie), is that the case? how is it used? and is it used on both UG and OH provisions?

Thanks in advance

It's just a stopper. When it's being pulled through a duct, in theory it'll catch on the edge of the duct, or overhead it'll catch in the pulley, so the engineer will know when to stop pulling.

The Corning equivalent has a cable gland to serve the same purpose.

Edited by troublegum (Sun 30-Jan-22 18:32:23)

In reply to a post by troublegum:

It's just a stopper.

I would have never figured that out in a month of Sundays

Tagging to last post

When a connectorised fibre cable is pulled through a duct to a property is the fully premade length (say 105m) pulled through the duct even if only a shorter length (say 70m) is required or is it cut down beforehand to save so much pulling as its going to only be cut off afterwards if its all pulled through.

I use 70m as an example as I believe typical lengths are 65m which would be too short and 105m would be too long

In reply to a post by dect:

Tagging to last post

When a connectorised fibre cable is pulled through a duct to a property is the fully premade length (say 105m) pulled through the duct even if only a shorter length (say 70m) is required or is it cut down beforehand to save so much pulling as its going to only be cut off afterwards if its all pulled through.

I use 70m as an example as I believe typical lengths are 65m which would be too short and 105m would be too long

Yes the full thing is pulled through and the excess cut off afterwards.

I suppose you could cut some off first, but it’s probably easier to pull it all through first, rather than estimate how much to cut off.

In reply to a post by troublegum:

Yes the full thing is pulled through and the excess cut off afterwards.

I suppose you could cut some off first, but it’s probably easier to pull it all through first, rather than estimate how much to cut off.

I was thinking of my own case where the duct comes up inside the property (not on the outside wall where space is not an issue) and the length of the duct to where the CBT will be located is known.

Does anyone know if the connectorised cables that transition from outside (black) to inside (white) can also be used with a CSP?

They can

In reply to a post by dect:

Does anyone know if the connectorised cables that transition from outside (black) to inside (white) can also be used with a CSP?

Does Openreach still stock this type of cable or have they moved completely to the flat cable?

Why the interest in dropwires dect? It’s a rather, err…. dry topic? 😎😀

In reply to a post by Pheasant:

Why the interest in dropwires dect? It’s a rather, err…. dry topic? 😎😀

Sorry not all questions can be jazzed up, just trying to help someone out.

In reply to a post by dect:

Does Openreach still stock this type of cable or have they moved completely to the flat cable?

Rather than leaving this question hanging the answer is yes, they do stock other connectorised cables that are not the flat type.

Back with another question

Are the inside out fibre cables used today by Openreach the same as BT item code 061820

In reply to a post by dect:

Are the inside out fibre cables used today by Openreach the same as BT item code 061820

Thanks for all the replies guys

Seems like these are still used for new builds but maybe not for existing properties.

That Commscope EH3241 fibre drop cable (now discontinued) is awful to work with. Must be a technique that demands practise. An awkwardly-routed drop cable needed re-routing and re-splicing. Using side-snips, the middle of the cable was chopped lengthways. But when pulling the two strengtheners apart to expose the fibre itself, the strengtheners kept snapping! Very brittle. Job done in the end, but it was a nuisance with the fear of damaging the fibre. By comparison, the Dexgreen inside/outside lead-in cable is a joy to handle.

https://i.imgur.com/o2CrlsQ.jpg

Thought I would revive this thread for one last question especially for Pheasant

When a CBT is at the top of a pole and the target property is accessed via a duct at the bottom of that pole does the connectorised cable (assume round not flat cable) get cleated to the pole with standard 5mm cleats and if so how far apart typically? also when using 19mm capping for the first 2.4m from the duct mouth would the connectorised cable still get cleated within the capping?

Sorry @dect - don't know.

In reply to a post by Pheasant:

Sorry @dect - don't know.

Thanks anyway

Yes, cleated down the pole with standard 4D ‘dropwire’ cleats. Flat cleats, for the ROC cables are available too,

No point in cleating behind the capping, why waste cleats ?

In reply to a post by Zarjaz:

Yes, cleated down the pole with standard 4D ‘dropwire’ cleats. Flat cleats, for the ROC cables are available too,

No point in cleating behind the capping, why waste cleats ?

Thanks for this info.