FTTP issues after Openreach fixed next doors problem

[Mark_Adddy]

On Tues 4th Feb an Openreach engineer attended a fault raised by my next door neighbour, which led to him working on the splitter at the end of my drive. After about 30 minutes of work my broadband connection disconneted, so I went to the end of the drive to tell him what had happened. He assured me it was nothing to do with his work, but as the splitter only serves two properties, their is a high probability the work he did disconnected our broadband connection. I noticed the problem because I was working from home at the time. In the 3 years since having FTTP we'd never encountered a problem until Openreach visited last week.

About 30 mins later the broadband connection was restored. However, at some point after that the broadband connection was disconnected again. I was unable to go back outside and tell him. He then left after fixing next doors broadband connection, with ours still showing disconnected.

I contacted BT and they told me I couldn't raise a fault because Openreach had declared a major incident in the area. Yet of the 4 properties on our road (all serviced by BT), only our property did not have a broadband connection.

So I stuck unable to raise a fault and the only course of action I had was to raise a complaint.

On Thursday morning (6th Feb) an Openreach Engineer visited the splitter again and when he left our broadband connection was restored. However, on Friday morning (approx 8am), the broadband connection was disconnected again. I was then able to raise a fault for an engineer visit, but the broadband was restored later that morning, so I cancelled the Engineer visit.

Again the broadband was disconnected on Sat morning (approx 8am) and later restored about 11:30am. It was disconnected again at 7:15pm and has stayed disconnected.

When it disconnects the PON light flashes on the ONT and eventually the LOS light turns solid red and the PON light goes off. We have an engineer booked Monday morning.

I feel powerless to do anything. Ringing BT hasn't helped. And the conduct of the Openreach engineer was very poor, but there isn't anyway to escalate this in BT or Openreach.

I wanted to POST on the forum incase anyone else has seen a similar problem.

[iniltous]

I suspect it’s a CBT in the jointbox at the end of your drive not the splitter ……splitters have CBT connected to them not customer connections , a splitter with only two CBT connections potentially would mean a much underutilised splitter asset , a CBT having only having two customer connections makes more sense…however that doesn’t really address your issue.

Customer connections on a CBT are ‘connectorised’ that’s the C in CBT ( block terminal the the rest of it ) so these are usually pretty robust, and not likely to be disturbed just by someone working in the jointbox , but it does seem too much of a coincidence that your issues started at the time the tech was working there .

If the issue isn’t a simple as the securing nut on your customer cable not being tight something easily checked by the tech you spoke to at the time you first noticed a problem, then it’s possible the cable itself has been damaged and will need to be replaced between the CBT and the CSP on your house wall, unfortunately these things happen , if you complained to the tech at the time and your connection appeared to be secure at the CBT , they are not likely to check much further than that ….hopefully it’s fixed on Monday

[36ULW]

As said I would imagine it is a CBT in the Joint Box at the end of your Driveway, not the Splitter given what the Engineer said about only two Subs being on it.

You can tell how many Subs are on a CBT purely by how many Connectors are in use. You can’t tell how many Subs are working on Splitter and or the SASA’s within it, unless for some reason the Engineer checked how many there are using NATO or ORSRIMS, which would be an unusual thing to do.

Anyway I suspect your fault may be caused by the folding/bending of the Cable that feeds your house. If the bend radius exceeds its limits it can cause high light loss to the point the ONT gets none at all.

Have come across that fault many a time, especially with Join Boxes becoming more and more congested due to PIA.

[Mark_Adddy]

Thank you for the replies and providing the right terminolgy. It is probably a CBT rather than a splitter and looked similar to pictures I found after your message.

Could I check whether a broken cable would disconnect the broadband service completely?

The reason I ask is that we had Internet connectivity this afternoon for a few hours. This happened yesterday and Friday also.

Also, there wasn't any problems with our broadband service until last week, when the OR engineer came to fix next doors fault.

[36ULW]

The Cable probably isn’t broken if enough Light can intermittently pass through to the ONT.

As it’s going on/off intermittently, especially when an Engineer works on the CBT in the Joint Box I’d hazard a guess, based on previous experience that either the COF250 Cable to the CBT or whichever of the 4 variants of Fibre Cable Lead to your house are being bent/folded beyond the radius of their limitations.

Light travels down a Fibre Cable using Wayleaves that are measured in Nanometres. If the Fibre Cable is bent/folded/twisted it can greatly reduce the amount of Light passing through it. 

I remember a few years ago I was doing a Provision Job to provide a second Fibre Line to a Sub. After Jointing the Fibre at the SASA I lowered the Node on the Mobra Arm and lowered it back into the.

Got back to the house and not only was the new Circuit not working but his other had gone off as well. Went back to the Splitter wondering how I’d managed to not connect up the new one and also by chance knock out his other circuit. Respliced both, went back into the house and both working fine.

Went back outside, put the Splitter back in the box when the Sub came out and said both had just gone off again?!?!

So I open the Node again, check I’ve got Light passing through both the incoming and outgoing side of the Splice, which I did so go in the house and yep, both working.

So I put the Splitter back in the box and yep, they go off again?!?!

After then getting the Splitter Node out of the box for what felt like the 100th time I then realised when I was lowering the Node on the Mobra Arm it was putting to much bend on the incoming COF215 Cable and the Light was going from a good -15dBm to over -50dBm.

So to fix the fault all I had to do was not fully lower the Node on the Mobra Arm before putting it back in the Joint Box.

[iniltous]

Fibre cable doesn’t like tight bends ,  a minimum bend radius needs to be maintained , if a bend is introduced that’s ‘tighter’ than allowed , and that could be something as simple as the cable being incorrectly secured in the box , so when the CBT is laid down flat (  its normal position  ) the cable is ‘squashed’ ,  and the ‘loss’ of light through this can be  such that the ONT isn’t able to maintain sync anymore , so if it were borderline critical light loss, your connection could be flaky , sometimes on sometimes off, rather than if the cable were completely broken then the LOS ( loss of signal  ) light would be permanently lit on the ONT .

TBH , its possible your issue is unrelated to the engineer working next door but I recon its too much of a coincidence not to be related, and the ‘fix’ is the same , examination of your cable for defects, a ‘bend’  can be unbent if that’s all it is  , or if the cable is thought now to be a liability, replaced , so until the tech turns up chances are your connection with be up and down ….obviously mention to the tech the background on this ,  they should measure the light levels and deal appropriately with the problem .

[Paul608085]

@36ULW @iniltous 

What is the minimum recommended bend radius for these types of fibre?

.

[iniltous]

Plenty of online resources , search minimum bend radius optical cables if interested , the principle is best explained using diagrams rather than text  , the ‘guidance’ I was once given was imagine the fibre going around the edge of a £2 coin , no tighter than that , but that was for internal ‘pigtail’ type single fibres used to connect equipment in racks etc . rather than external grade cables ……the type of connectorised cable used by OR  from a CBT to the CSP on the customer’s house wall has a strength member or strength members within the cable jacket , so it’s by its nature not particularly flexible, bend these cable too much ( by standing on one that’s not restrained  ) and these strength members can fracture allowing the optical fibre inside to be deformed and therefore introduce high losses .

[Paul608085]

@iniltous 

Thanks for the reply.

"Plenty of online resources , search minimum bend radius optical cables if interested , the principle is best explained using diagrams rather than text "

I understand the principle, I started working with fibres of different types at BT TV broadcasting, from around 1990 until I retired from there 4 years ago, but my understanding was that different types of fibre had different minimum bend radius?

"the ‘guidance’ I was once given was imagine the fibre going around the edge of a £2 coin , no tighter than that "

That is a lot tighter than I would ever have routed a fibre cable!

.

[WSH]

Years ago, I was taught 4x the diameter for copper and 10x the diameter for fibre but that will be for fibre patch cables.  I would imagine it's somewhat different for the cables delivering broadband.