RJ45 crimp tool

Buying an RJ45 (technically 8P8C) crimp tool should not be this hard!

When terminating a network cable, there are a few things to bear in mind, so just a quick reminder...

  • Cat5e or cat6 are different. Cat6 is better, but thicker. With the right tools cat6 can be easier. Using cat6 cable, and connectors, and patch leads, can mean faster than 1Gb/s networking is possible. With cat5e it is 1Gb/s max. In any case you need the right kit, but if putting wires in walls, using cat6 is sensible to future proof. Note, the easy way to spot cat6 rather than cat5e is the plastic cross piece in the cable separating the pairs (also, thicker wire and tighter twists).

    Cat6 cable with white plastic cross piece in middle
  • Solid and stranded cable are different. Stranded is for "flex", i.e. the patch leads, etc - things that move and get plugged in and unplugged. You put plugs on the end of stranded cable. Solid is for infrastructure, the wiring in the walls - stuff that does not move. You generally connect solid cable only to sockets, using IDC and punch-down tool.
  • Internal and external cable is different. External has an extra layer which is UV resistant and so will not break and crack if in sunlight. You can get external for burying in the ground as well. It will usually have a sort of gel in it to keep water out, which is messy (best to use gloves when working with it).
    Cat6 gel filled external cable

In any case, please use the right plugs and tools for the cables, for best results.

Using the right plugs

The plugs are called RJ45, which is the specific type of plug with 8 contacts. There are smaller RJ11 and RJ12 plugs, used for telephone lines in US but seen less in UK, and are not for network cables.

You can put plugs on solid cable - but use the right type of plugs! There are connectors rated for use on solid cable, and they work. The connectors designed for stranded cable only seem to work, but often stop working quickly, as they usually only have a blade that pushes in to the strands - which you can't do on solid cable. Obviously, you need to be extra careful with plugs on solid cable to ensure strain relief on the sleeve of the cable, etc. I am using in cases where the wires won't be moving, for infrastructure where a socket one end of cable, but a back to back RJ45 socket strip in a rack in my loft - simply because it is way easier to use than a strip with IDC connectors at the back - hence plugs on solid cable.

So, yes, get the right connector for the cable type (solid/stranded and cat5 or cat6)!

Contacts for solid (left) and stranded (right)

Passthrough plugs, for the win

This is basically the revelation that inspired this blog and prompted me to get a new crimp tool. I have had a very good crimp tool for a long time that does cat5 and cat6 cables nicely.

Pass through (left), and capped (right) plugs

However, with a traditional (capped) plug you need to:

  • Line up the wires, in order, flat
  • Cut the wires straight, at exactly the right length
  • Feed the wires in to the plug, all the way to the end
  • Crimp
  • Test

The issues are...

  • You have to get the length right so that when the wires are all the way in to the plug the sleeve is in the strain relief clamp at the back of the plug. Too short and they do not go all the way - which may work initially but is a bad connection, or may not work at all. Too long and you don't clamp on the strain relief, which works perfectly until any strain on the cable causes the individual wires to come disconnected. Getting it exactly right takes practice and means measuring.
  • You have to feed the wires in to the plug all the way to the end - even with a transparent plug it can be hard to see that all 8 wires have gone neatly to the end. If any are short you can have a bad connection or no connection.
  • Done right, there is not a lot of length of straight wire to feed in, you have a small gap between end of sleeving and the connectors, which often can have cables twisted around to get in the right order, and is worse with some of the cat6 cross piece there. This means that keeping those 8 straight bits of wire straight as you feed in to the plug can be really hard. It means you can have a wire not go all the way, or even the wires moving around and changing position, which is hard to notice.

The answer is so obvious I do not now why it was not done like this in the first place - passthrough connectors. With these, the wires push all the way through the plug and out the end. This means:

  • You can cut with much longer straight section of wires, and do not even have to cut the wires straight across. There is plenty of room to feed them in to the plug and through.
  • It is simple to ensure you have pushed all the way to get the strain relief clamp on to the sleeving.
  • You can see the wires are all the way through and not short, before you crimp.
  • You can see the wires are in the right order, before you crimp

The only down side is you need, ideally, a new crimp tool that not only clamps the strain relief and the contacts but also trims the wires cleanly at the end of the plug. Trying to do this with cutters is almost impossible, and if you do not cut the wires neatly they can short to each other at random times in the future. It can be done with a blade, but can be dangerous and also somewhat tricky. You really need the right tool.

Cable in pass through plug

The right tool

Getting the right tool should be easy, but like all tools, you get what you pay for. I did get one from Amazon that seemed OK, but the trimming of the wires was unreliable, so sent back.

I was recommended the Klein Tools one, which is a lovely tool, but I managed to order the one that is not for pass through, so sent back.

I found the Klein Tools VDV226-110, which is nice. RJ11/12 and RJ45, passthrough, stripper, cutter. Perfect, so I ordered. Then I found the Klein Tools VDV226-005 which is just the RJ45 crimp and trim, no cutter or stripper. I never used the cutter and stripper with my old crimp tool (I have nice cutter and stripper anyway in my cable toolkit). I never crimp RJ11/12. So this would be way neater and smaller, but changing my order was not possible it seems.

I ordered the Klein Tools passthrough plugs (VDV826-763 and VDV826-702) as well, just to see if any different to use than the cheap ones from Amazon.

Even though the order (on 14th Feb) was on basis that "Available for immediate dispatch", sadly, something about Texas, weather, COVID, and all sorts, means nobody in the UK seems to have any of these and it takes weeks to get them. Arrrg!

The good news is that, finally, Amazon got FBA stock, so I cancelled the order from the US, and got for Amazon (VDV226-005, and VDV226-763).

The end result

I finally have the VDV226-005 - note it is not racket based, but works well.

Klein Tools VDV226-005

This makes it easy to crimp and cut the cables.

Crimping and trimming

The end result is very neat...

The end result, neat and secure


  1. You are braver than I crimping your own connectors. I always punch down fixed cable to sockets and then buy patch cords with factory crimped plugs. Where there isn't space for a regular socket I sometimes use a surface mount socket on a flying lead. Something like https://cpc.farnell.com/pro-signal/psg08000/socket-surface-rj45-cat6-single/dp/CS16167

    1. Whilst I have never been brave enough, or had the tools, to terminate fibre - network cable is a doddle. As always, use the right tools. And, I highly recommend the right tester (I use a Fluke Microscanner2).

    2. I've only ever done a few sockets and gave up on them as had nothing but problems with linking up at 100Mbit when they all seemed to be punched cleanly. Get rid of the socket and stick RJ45 on the end instead, works fine.

      Thus is the problem when its just a few for home use so not cost effective to get the absolute top-end tools. Although I'm on my fourth RJ45 crimp tool, the second for EZ-RJ45 as I had the same issue as mentioned in this article with the cheap ones not cutting the cable properly.

  2. Don't confuse CAT 6A (Augmented) with CAT 6. CAT 6 is great, conversely you really don't want CAT 6A it is a monster of a cable.

  3. In theory you can run 2.5gig on cat5e cable using 2.5GBASE-T, but I've never actually seen a switch or NIC that supports it.

    And if you are putting in new cables, then cat6 (or 6A) makes sense.

  4. Yes, exactly this. We only use the pass-through RJ45 plugs now. Saves vast amounts of time and effort. And almost zero failed crimps, which always result in cut-off and wasted time and money and shortening the length of available cable.

    Somehow I thought I found out about these products from your blogs, but if you are only now posting about them as a bit of a new revelation then I cannot have done.

    With some wall-mounted WiFi access points adding a rubber strain-relief boot to the arrangement just makes it all too difficult and hard to fit. So we don't add boots to those.

    We found cat7 in a (large) residential dwelling. We think builder or designer got carried away and went with "bigger number is safest". Current owner is running a 4K video matrix via a 10 Gbps (I think) Ethernet switch over it now. But most of the cat7 wall outlets are just connected to a regular PSTN. Good use of high end cables.

  5. I found another problem with this though, getting decent EZ-RJ45 plugs in relatively small quantities but not paying the earth for them.


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