Cabling from outside to master socket

Hello everyone. Compliments of the season to you and Happy New Year! Attached to the front of my house is a black box (sort of sausage shaped, approximately 5 inches in length) and from this is a white cable which goes through the wall at the front of the house, into my loft, is stapled to the rafters and then drops down into my room and attaches straight to the master socket (NTE5a), which is the only socket in the property. The white cable is thin and has four cores - BLUE, BROWN, GREEN and ORANGE. As the attenuation on my line is quite high for my distance from the cabinet (I'm on FTTC) I was wondering if this is the correct cable and if it being stapled to the rafters would affect it at all. Should it be an external wire coming into my house? What is the most up-to-date wiring colours? Just trying to tweak wherever possible before my fibre is upgraded to the 80/20 package. Many thanks for reading.

Not your cable to fiddle with, and changing just a metre or two is not going to affect the attenuation to any great extent

Good pictures might let someone identify whether genuine cable or a previous residents DIY bodge

It's not so much as what colours are right as what pairs are right. There are numerous colour codes out there and indeed marking codes from times before man could make coloured wires.

MrSaffron and partial - thanks for your quick responses. If the cable turns out to be rubbish I shall ask BT to replace.

Am I right in thinking the pair connected in the box outside my house on the wall need to match the pair connected to A and B in the master socket then? Thanks again.

The pairs don't need to match, so long as pair is used rather than being a split pair

Thanks MrSaffron. Just letting the OCD get the better of me. Sounds like no point in replacing it then! Just thought attenuation of 19.1db was quite high to say I'm 300 metres from the cabinet is all.

Just stripped back the white outer sheath and the cores aren't twisted. Is this correct? Thanks and apologies for more questions. I have previously trimmed back cable on a master socket and used an idc tool to remake the connections and saw the attenuation drop a little! 🙂

In reply to a post by giggsy1977:

Just stripped back the white outer sheath and the cores aren't twisted. Is this correct? Thanks and apologies for more questions. I have previously trimmed back cable on a master socket and used an idc tool to remake the connections and saw the attenuation drop a little! 🙂

Firstly, not your cable to be stripping back, secondly how are you totally sure it is not twisted? Cabling is not always obviously twisted.

The black box is likely just a BT approved joint enclosure such as this snapped and closed:
https://www.picclickimg.com/00/s/OTAwWDE2MDA=/z/xdMA...

It is standard to use internal vs external cabling, one white and one black. Drop cable would not typically be used internally, it will often run outside, drill through the wall and straight into the master. If there's internal wiring, it should be white as yours is.

As a reference I have an attenuation of 13.9 and my green FTTC cab is less than 50m away. It all depends how the cabling is routed.

Third point, you state you are upgrading to 80/20, although based on your signature "Predicted speed 54.7Mbps down/15.7Mbps up. Actual speed 42Mbps down/4.5Mbps up" indicates you already had an 80/20 package on BT?

Note, DLM is the same on Sky and BT, so in theory your speeds could end up the same as with BT. Based on the noise margin of 13.1 in your signature, you know it is extremely unlikely you will get 80 down right? I would suggest 50 to 60 is likely, depending how the line stabilises.

Your link to a pic doesn�t work for me. Just a blank screen.

When I read the OP I thought of the waterproof jointers?

In reply to a post by RobertoS:

Your link to a pic doesn�t work for me. Just a blank screen.

When I read the OP I thought of the waterproof jointers?

that's what I had linked too - I will amend the link when I get on a PC.

ukhardy07 - thanks for your reply. I appreciate the cable before the master socket is mine and as the socket is easily accessible (it's not attached to the wall) I just had a look at the cable but have left it connected. The cable from the black box immediately outside the house is white and runs from outside straight to the master. There are no joints between the black box and the master that I know of.

I'm currently on a 40/10 package with Sky. I was on an 80/20 package with BT originally but downgraded as there was no real benefit in actual use.

I'm getting the free upgrade to 80/20 that Sky are rolling out, and seeing as my noise margin has since dropped from 13.1db to 10.1db I wondered if I could do anything to get it back up a bit to maximise the speed I would get once upgraded as the faster speed is now more important than it was previously.

BT cable using these colour codes was normal in the 1970s, Orange and Blue were the A & B wires, normally for internal wiring the Green and Brown would be used for the ring wire and recall, I have to be honest and say twisted pairs wasn't something engineers ever thought about in those days as it was a voice only service.

They are also the same colours for the currents Openreach internal 2 pair

So the cable could be old or newish! 🙂

Well I�d suspect it�s new-ish, as the old cable with those colours was often grey on its exterior.

As someone else posted, I suspect you are barking up the wrong tree, a couple of metres of cable is highly unlikely to be the cause of higher than expected attenuation.

Edited by Zarjaz (Wed 02-Jan-19 13:33:11)

There was a period before the new colour coding came in when the outer sheathing was white, the fact that its stapled rather than clipped probably helps to date the work.

I do think that 19.1 dB attenuation for what appears to be 300ish metres (admittedly as the crow flies) does sounds a lot, even if it was aluminum I wouldn't expect it to be that high.

Strange things happen - as I suspect you know.

Straight line distance from my place to the cab, 50m, actual pair length 181.

" I appreciate the cable before the master socket is mine"

Is there a "not" before 'mine' missing?

Ha, good spot. They should indeed be a "not" in there! I'm really surprised that when at a previous house I trimmed back the cable that the snr increased by 3db, unless it was just coincidence?

In reply to a post by giggsy1977:

Ha, good spot. They should indeed be a "not" in there! I'm really surprised that when at a previous house I trimmed back the cable that the snr increased by 3db, unless it was just coincidence?

SNR varies throughout the day, e.g. in the evening it is often lower. It does not usually vary by 3db however... I will agree with others, this is not the cause of your attenuation and playing around is more likely to induce a fault than lead to any benefit.

I'm sure you're right ukhardy07 - it was rock solid at that though. Probably something else. Ne connection in the cabinet or a neighbour getting some electric that interferes. Will need to move if I want faster fibre I guess! Wonder how much Openreach would charge to fit one long continuous brand new copper cable between my house and the cabinet if I bought the cable?! Ha!

Isn't going to happen, also if you think this is the only joint in your line, you are in for a surprise.

In reality it probably would not even make a huge difference unless there is Ali etc used.

Jelly crimps which is what is likely used here have negligible / no impact on your line speed.

My house was built in the early seventies so don't know if that means copper or aluminium! It would be great to have fibre from the exchange to the cabinet and just one complete length of good copper to the house though (with no joints!)

Not going to happen

I know, I can dream though! No Virgin around here so stuck with FTTC for the foreseeable future. Thanks for your input everyone. Shall drive myself mad with something else instead! 😂

In reply to a post by Zarjaz:

Strange things happen - as I suspect you know.

Straight line distance from my place to the cab, 50m, actual pair length 181.

Morning Zarjaz

One of them being the distance measured using a JDSU, I know first hand the actual cable length from the PCP to my property (both UG and OH) and the difference between that and the JDSU reading is around 400m

My measurement was made with a proper mole ... it said 181 metres and that�ll be what it is. I have trusted it, and used it for 21 years, it only does one thing, but does that really well.

The results provided by the TDR function on a JDSU (never used an Exfo) are just guidelines.

It's good to know they are still being used.