How to repair a CAT 6 cable
Discussion
We've had some work done on the house at Oxgreen Towers, and I told the workmen to lay some pre-made CAT 6 cables underneath the flooring. Unfortunately, one of those cables has got damaged at one end - somebody has managed to cut half-way through it.
The work is now complete, so lifting the flooring is not an option. The only option, it seems to me, is to cut off the damaged end of the cable and fit a plug myself. But I've never done it!
I've watched a couple of YouTube videos, and it seems doable. I don't own an RJ45 crimp tool, but I can buy one.
But I'm a bit confused about "A" and "B" wiring schemes. How do I know which scheme I should use when I fit a new plug to an existing pre-made cable? I suppose I could cut both the ends off the cable and put my own plugs on each end, and then I guess it only matters that I use the same scheme at each end. Is that right?
How easy is this? Do I need to find someone who's done it before and offer them some beer money, or is is something I can successfully learn to do myself?
Edited to add: Thanks to the mods for correcting my horrendous typo in the thread title!!
The work is now complete, so lifting the flooring is not an option. The only option, it seems to me, is to cut off the damaged end of the cable and fit a plug myself. But I've never done it!
I've watched a couple of YouTube videos, and it seems doable. I don't own an RJ45 crimp tool, but I can buy one.
But I'm a bit confused about "A" and "B" wiring schemes. How do I know which scheme I should use when I fit a new plug to an existing pre-made cable? I suppose I could cut both the ends off the cable and put my own plugs on each end, and then I guess it only matters that I use the same scheme at each end. Is that right?
How easy is this? Do I need to find someone who's done it before and offer them some beer money, or is is something I can successfully learn to do myself?
Edited to add: Thanks to the mods for correcting my horrendous typo in the thread title!!

Edited by Dr Mike Oxgreen on Sunday 3rd March 15:40
Rather than piddle about buying crimp tools & the like look around for soneone who does AV installs - round here they advertise in the back of the local magazines, or ask on your local Facebook group. It isn't difficult but it is fiddly & you'll probably never use the tool again.
I'm tempted to ask how you managed to get installed cables with plugs on but I'll not bother. This scenario is why you should run cabling to jack points & use a patchcord to connect to the equipment.
I'm tempted to ask how you managed to get installed cables with plugs on but I'll not bother. This scenario is why you should run cabling to jack points & use a patchcord to connect to the equipment.
It's dead easy - I've connected the wiring in our house after the electrician left the wiring blank (as planned) at the 'distribution' end.
Ideally you need a crimp tool, tester (which will solve your A/B issue, but so will looking at the other end assuming you know where it is) and obviously some 'ends'. The tolls are only a few £ and the ends pennies so best to do a proper job in my view.
If you can get yourself to Leatherhead easily (and time is not an issue) then I can arrange for my 'kit' to get there for you to borrow - I'll even chuck in a few ends for you to use as I no longer have any need for the 100 odd I've left! But given the cost of the tools you'd be better off buying your own unless you literally live down the road as you'd spend more getting there than the cost of buying!
Ideally you need a crimp tool, tester (which will solve your A/B issue, but so will looking at the other end assuming you know where it is) and obviously some 'ends'. The tolls are only a few £ and the ends pennies so best to do a proper job in my view.
If you can get yourself to Leatherhead easily (and time is not an issue) then I can arrange for my 'kit' to get there for you to borrow - I'll even chuck in a few ends for you to use as I no longer have any need for the 100 odd I've left! But given the cost of the tools you'd be better off buying your own unless you literally live down the road as you'd spend more getting there than the cost of buying!
Years ago ,on a Cat 5 job ( and remember this was cat 5, slow speeds) , we had a fault where builders had cut through a cat5 cable. As an emergency repair, we cut the cable and terminated/ jointed it on a cat 5 socket. Not exactly approved, but similar to terminating cable on a socket, at both ends and then patching through on a patch cable.
Dr Mike Oxgreen said:
Thanks for the pointers so far!
Looking at the connector end-on I think it does look like B wiring.
I think I’m going to buy some connectors and a crimp tool off Amazon and have a go. Will report my success or abject failure!
When you cut the damaged connector off you can use a multimeter to test continuity between each wire and the pin in the connector, that'll tell you for certain how it's wired.Looking at the connector end-on I think it does look like B wiring.
I think I’m going to buy some connectors and a crimp tool off Amazon and have a go. Will report my success or abject failure!
keirik said:
I love the people that say its easy.
I always cock it up, even with proper tools. I struggle to get the cables to sit in the right places, it ge erally takes me at least 3 goes per end!
It could be because my eyes are old I suppose, I do struggle to see it clearly
The I always cock it up, even with proper tools. I struggle to get the cables to sit in the right places, it ge erally takes me at least 3 goes per end!
It could be because my eyes are old I suppose, I do struggle to see it clearly
OP has hands of a doctor though. Admittedly, that could mean surgeon or drunk.....or both.
I have terminated 2 cat 6 cables and they both tested OK first time. To be fair I spent my youth installing B&O systems and joining masterlink cables for fun. But, I still think with the right tools cat 6 is possible for most.
I wouldn't crimp solid core CAT6. I've done it before and it worked, but it was unreliable and didn't perform very well. Better to punch it down into the terminating plate, or if you're trying to join two cables together use something like this - https://www.amazon.co.uk/dp/B003OSTGK0/ref=cm_sw_r...
If it's stranded cable you should be ok crimping though. If you've never done it before and you have a limited amount of cable to work with I'd suggest getting a pro in.
As said above CAT6 cable runs shouldn't have been terminated with plugs, they should have ended up unterminated in the wall voids, at wall plates (punched down) or a patch panel (again, punched)
If it's stranded cable you should be ok crimping though. If you've never done it before and you have a limited amount of cable to work with I'd suggest getting a pro in.
As said above CAT6 cable runs shouldn't have been terminated with plugs, they should have ended up unterminated in the wall voids, at wall plates (punched down) or a patch panel (again, punched)
Edited by Durzel on Monday 11th March 01:54
techiedave said:
Mr Pointy said:
I'm tempted to ask how you managed to get installed cables with plugs on but I'll not bother. This scenario is why you should run cabling to jack points & use a patchcord to connect to the equipment.
I am surprised at that too. TBHEven if I had asked them to chase the cable into the wall and terminate with a wall socket, they could still have damaged the cable part way along and I'd be in a worse position.
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