Quick Answer
What You Need
Before you start, gather these tools and materials. Using the right equipment makes the difference between a reliable termination and a frustrating rework session.
Crimp Tool
A ratcheted RJ45 crimp tool is essential. The ratchet mechanism ensures you complete the full crimp cycle every time, which means consistent contact blade penetration and reliable strain relief. For pass-through connectors, use a crimp tool that trims the excess wire during the crimp.
RJ45 Connectors
Match the connector to your cable category. Cat5e cable uses 24 AWG connectors, Cat6 uses 23 AWG connectors. Pass-through connectors are strongly recommended because they let you verify wire order before you commit to the crimp.
Cable Jacket Stripper
A purpose-built cable stripper removes the outer jacket without nicking the insulation on the twisted pairs inside. This is the step where most beginners accidentally damage wires, so a tool with a preset or adjustable blade depth is worth the investment.
Cable Tester
Never skip testing. A cable tester verifies that all eight pins are wired correctly and there are no opens, shorts, or crossed pairs. Even experienced installers test every single termination.
Step-by-Step: How to Crimp an RJ45 Connector
This guide uses the T568B wiring standard and a pass-through connector, which is the most common setup for new installations. If you need to follow T568A or use a standard connector, the same process applies with minor adjustments to wire order or insertion technique.
Measure and cut the cable to length
Determine the cable run distance and add 1 to 2 feet of extra slack at each end for service loops. Cut the cable cleanly using the cutter built into your crimp tool or a dedicated cable cutter. A clean, square cut makes the next step (jacket stripping) easier and more consistent.
Strip the outer jacket (1 to 1.5 inches)
Place the cable into your jacket stripper approximately 1 to 1.5 inches from the end. Rotate the stripper around the cable once to score the jacket, then pull the cut section off to expose the twisted pairs inside. Check that you haven't nicked any of the individual wire insulation. If you see copper or damaged insulation, cut the cable back and strip again.
Untwist and straighten the individual wires
Separate the four twisted pairs and untwist each pair down to where the jacket begins. Straighten every wire as flat as possible by running each one between your thumb and forefinger. The straighter the wires, the easier they are to arrange in the correct order and the more smoothly they'll slide into the connector channels.
If your cable has an internal spline (common in Cat6), trim it flush with the jacket before proceeding.
Arrange wires in T568B order
Hold all eight wires flat and parallel between your thumb and forefinger. Arrange them in T568B order from left to right:
For the full color code reference including T568A, see our RJ45 pinout guide.
This is the most error-prone step. Take your time. Double-check the order before moving on. The two pairs that get swapped most often are green and blue (pins 3-6 and 4-5).
Trim wires to even length
With the wires held in order, use flush cutters or the cutter on your crimp tool to trim all eight wires to the same length. Leave about half an inch of exposed wire beyond the jacket. The cut must be perpendicular to the wires so every conductor is exactly the same length. An uneven trim is the number one cause of pins that fail to make contact after crimping.
Insert wires into the RJ45 connector
Hold the connector with the clip facing down and the gold contact pins facing up. Slide the arranged wires into the connector while maintaining their order. Apply firm, even pressure.
For pass-through connectors: Push the wires all the way through until they extend out the front of the connector. This is the key advantage of pass-through design - you can see every wire color at the tip and confirm the order before committing to the crimp. See our pass-through vs standard connector guide for a detailed comparison.
For standard connectors: Push the wires in until each conductor reaches the front wall of the connector. You should be able to see each wire tip through the clear plastic at the front.
In both cases, make sure the cable jacket extends into the connector body far enough that the strain relief clamp will grip it during crimping.
Verify the wire order through the connector
Before you crimp, look at the wires through the connector one more time. With pass-through connectors, check the color order at the wire tips extending from the front. With standard connectors, look through the clear plastic housing.
Confirm T568B from left to right (clip down): orange-white, orange, green-white, blue, blue-white, green, brown-white, brown. Fixing a mistake now takes seconds. Fixing it after crimping costs you a connector.
Seat the connector in the crimp tool and squeeze firmly
Place the loaded connector into the crimp tool die. Push the connector all the way into the die until it stops. Squeeze the handles together fully and with steady pressure until the ratchet mechanism releases. The ratchet is there for a reason - it ensures you complete the full crimp cycle, which does three things simultaneously:
- Drives the contact blades through the wire insulation to make electrical contact with the copper conductors
- Clamps the strain relief onto the cable jacket to prevent pull-outs
- Locks the connector housing so the plug clicks securely into jacks
Trim the excess wire (pass-through connectors)
If you're using a pass-through connector and your crimp tool automatically trims during the crimp cycle (like the EzEX Crimp Tool), this step is already done. If your tool doesn't auto-trim, use flush cutters to clip the wire ends flush with the front face of the connector. Don't leave any wire protruding - it can snag or interfere with the jack contact.
Test the termination with a cable tester
Plug the terminated cable into a cable tester and run a wiremap test. The tester will check all eight pins for continuity and correct wiring. A passing test confirms:
- All 8 conductors have continuity (no opens)
- No pins are shorted together
- No wires are crossed or reversed
- No split pairs (wires from different pairs swapped)
If any pin fails, cut the connector off, strip fresh cable, and start from step 2. Do not attempt to re-crimp a failed connector.
Common Mistakes (and How to Avoid Them)
Most RJ45 crimping failures come from the same handful of errors. If your terminations aren't passing the cable test, check for these problems first.
Stripping too much or too little jacket
Too much exposed wire means untwisted pairs sitting outside the connector, which increases crosstalk and fails certification tests. Too little means you can't arrange the wires properly or the jacket won't reach the strain relief. Aim for 1 to 1.5 inches every time.
Uneven wire trim
If the eight wires aren't cut to exactly the same length, the shorter ones won't reach the contact blades inside the connector. This is the single most common cause of open pins. Use a flat, perpendicular cut with sharp cutters.
Wires not pushed fully into the connector
Every wire must be fully seated against the front wall of the connector (or pushed through on pass-through models). If a wire is even slightly short, the contact blade won't pierce its insulation during the crimp. Visually confirm seating before you crimp.
Releasing the crimp tool before the cycle completes
The ratchet mechanism on a quality crimp tool is calibrated to deliver the exact amount of force needed. Releasing early means incomplete blade penetration, weak strain relief, or both. Let the ratchet click and release on its own.
Using the wrong connector for the cable type
Cat5e connectors on Cat6 cable and Cat6 connectors on Cat5e cable both cause problems. The internal wire channels are sized for specific conductor gauges. Always match the connector to the cable category.
Nicking wires during jacket stripping
If your cable stripper blade is set too deep, it cuts through the jacket and into the individual wire insulation underneath. Damaged insulation can cause shorts between conductors. Use a tool with adjustable or preset blade depth and check the wires after every strip.
Pro Tips for Speed and Consistency
Once you have the basic process down, these techniques will help you work faster and reduce your rework rate.
- Use pass-through connectors. The ability to see wire colors at the tip before crimping eliminates the most common source of errors. Professional installers who switch from standard to pass-through connectors typically see their rework rate drop by 50% or more.
- Develop a consistent wire-ordering technique. Start by separating the orange and brown pairs to the outside, then slot green and blue in the middle. With practice, you'll arrange all eight wires in under 10 seconds.
- Keep your wires straight. Spend the extra two seconds straightening each wire before you arrange them. Kinked or curved wires fight you during insertion and shift position inside the connector.
- Trim with sharp cutters. Dull cutters crush the wire ends instead of cutting cleanly, which makes them harder to insert and can push conductors out of alignment. Replace or sharpen your cutters regularly.
- Crimp at a table, not on a ladder. If you're terminating cable pulled to a new location, leave enough service loop to bring the cable end down to a stable work surface. You'll crimp faster and with fewer errors than doing it overhead.
- Test every single termination. Even if you've done ten thousand crimps, test every one. A simple cable tester takes five seconds and catches problems that are invisible to the eye.
- Buy the right connector for the job. Having both Cat5e and Cat6 connectors on hand means you never have to force a mismatched connector onto the wrong cable.
Recommended Gear
Here's what we recommend for a complete RJ45 termination setup, whether you're doing your first cable or your thousandth.
Starter Setup
Everything you need for basic Cat5e and Cat6 termination
Affordable entry point with pass-through convenience. Ideal for home networking and small projects.
Professional Setup
For installers handling Cat5e through Cat6A on commercial jobs
The EzEX Crimp Tool handles the full EZ-RJ45 and ezEX connector family with automatic pass-through trimming. The MapMaster identifies every fault type including split pairs.
All-in-One Kit
Crimp tool plus connectors in a single package
Includes the EzEX Crimp Tool, a selection of EZ-RJ45 and ezEX connectors for both data and voice, and a carrying case. Everything in one box.
Frequently Asked Questions
What tools do I need to crimp an RJ45 connector?
You need four things: a crimp tool designed for RJ45 connectors, a cable jacket stripper, RJ45 connectors matched to your cable type (Cat5e, Cat6, or Cat6A), and a cable tester to verify your termination. A pass-through crimp tool like the EzEX Crimp Tool is recommended because it trims excess wire automatically during the crimp.
Should I use T568A or T568B wiring?
T568B is the most common standard in the United States and is used in the vast majority of commercial and residential installations. Use T568B unless your existing infrastructure specifically uses T568A. The most important rule is consistency: every termination in a run must use the same standard on both ends. See our RJ45 pinout guide for the complete color code reference.
What is a pass-through RJ45 connector?
A pass-through connector has an open front that allows the individual wires to pass all the way through the connector body. This lets you visually verify the wire color order before crimping, which significantly reduces wiring errors. The excess wire is trimmed flush during or after the crimp cycle. Read our full pass-through vs standard connector comparison for more detail.
How much jacket should I strip from the cable?
Strip approximately 1 to 1.5 inches of the outer jacket. This provides enough exposed wire to untwist, arrange, trim, and insert into the connector while still allowing the cable jacket to sit inside the connector's strain relief area. Stripping too little makes it hard to arrange the wires. Stripping too much leaves exposed, untwisted pairs outside the connector, which increases crosstalk.
Why does my RJ45 crimp keep failing the cable test?
The most common causes of failed crimps are: wires not pushed fully into the connector before crimping, uneven wire lengths causing some conductors to not reach the contact blades, releasing the crimp tool before the ratchet completes its full cycle, and using a connector rated for a different cable category. Verify wire seating visually before every crimp, and always complete the full crimp cycle.
Get the Right Tools for the Job
Quality terminations start with quality tools. Browse our full catalog of crimp tools, connectors, strippers, and testers to build your setup.