This project shows how to make an Ethernet network patch cable (or straight-through cable) by wiring and crimping an RJ45 plug.
Ethernet Cable Tools and Materials
Making an Ethernet network cable is easy and inexpensive. To make your own cables you’ll need:
- Cable Crimp, Cut & Strip Tool
- Cat5E Crimp Connectors (plugs)
- Bulk Cat5e Ethernet Cable
- Cable Labels – optional but very helpful
Note: If using Cat6 cable be sure to use only Cat6 rated components – cable, crimp connectors and jacks – to attain the full Cat6 10 gigabit/second (10GBASE-T) performance rating. For most home users Cat5e cable is more than sufficient because it supports 1 gigabit/sec (1000BASE-T) data rates and most home switches/routers only have 1 gig Ethernet ports. See How to Wire a Cat6 RJ45 Ethernet Plug for instructions.
EIA/TIA T568A and T568B Ethernet Cable Wiring Standards
Cat5e and Cat6 Ethernet cables may be wired per two standards: T568A or T568B. The differences between the two are minor and the important thing is to pick a standard and stick with it. If you already have Ethernet wiring installed, examine how the wall jacks are wired and continue with that method for consistency. I prefer T568B because it’s how I was trained and it’s the most popular in standard for office and commercial networks.
The EIA/TIA T568A crimp connector wiring diagram is:
and the EIA/TIA T568B wiring diagram is:
The difference between the two standards is the Green/Green Stripe and Orange/Orange Stripe wire positions are swapped.
When making an Ethernet network cable be sure to wire both ends the same as illustrated in the following diagram:
If you inadvertently wire one end of the cable as T568A and the other as T568B you’ll have created an Ethernet crossover cable. Crossover cables are useful in limited situations such as when connecting two network devices directly without an Ethernet switch between the two.
How to Make an Ethernet Network Cable Cat5e Cat6
If you’re making an Ethernet patch cable for short runs from the wall jack to desktop or rack mount equipment, pull enough bulk cable from the box to span the needed distance – typically 2 to 10 feet or so for patch cables. For longer Ethernet cable runs through the walls and attic, fish or pull the cable with a couple of feet extending beyond the wall because the RJ45 jacks or crimp connectors (plugs) are wired-on after the cable is pulled.
Sometimes a combination of short patch cables and long cable runs for things like a Power over Ethernet (PoE) network camera are needed. The camera in this instance has an on-board Ethernet jack (female connector) and requires a cable terminated with a RJ45 plug (male connector). The solution is illustrated in the following diagram. Take care to wire all jacks and plugs to the same T568A or T568B standard:
Cat6 Ethernet Cable Wiring
Cat6 and Cat5e RJ45 plug wiring steps are very similar except that Cat6 plugs use load bars to align the thicker Cat6 wires with the plug pins. See How to Wire a Cat6 RJ45 Ethernet Plug for details.
Cat5e Ethernet Cable Wiring Steps
Begin by cutting the cable for a clean and even end:
The TRENDnet TC-CT68 Professional Crimp Tool wire cutter blade works well:
Strip the Outer Insulation Jacket
Place about 2 inches of Ethernet cable through the round pocket of the tool to score the outer insulation jacket. The blade is set very shallow to cut only the jacket and not the wires. I prefer to hold the crimp tool steady while turning the cable back & forth to score/cut the jacket:
View of the cable on the other side of the jacket stripper:
After scoring, bend the cable to break the insulation jacket cleanly in two and pull it off:
Ethernet Cable Rip Cord
The purpose of the silk-like rip cord is peel open the outer insulation jacket by pulling it down the cable to expose the twisted pair wires. The reason for this is you may have cut the twisted pair wire insulation when stripping the outer insulation jacket which could create a short-circuit if the wires were to make contact. I’m using Unshielded Twisted Pair (UTP) Cat5e cable where a small nick in the wire insulation is less likely to cause a short. Shielded Twisted Pair (STP) cable has a thin metal foil jacket for noise resistance and is more prone to shorting (grounding) if the inner wire insulation is damaged.
Pull the rip cord to tear open the outer insulation jacket. This exposes a fresh section of twisted pair wires with no risk of insulation damage and potential shorts:
Cut off the outer insulation jacket with scissors (best) or knife (hold the knife blade away from the twisted pairs to avoid damage), then cut the twisted pairs to about 2 inches long using the crimp tool cutter:
Order and Straighten the Ethernet Cable Wires
Untwist the wire pairs, straighten the wire by pulling each between your forefinger & thumb, and arrange the wire colors per the T568A or T568B standard. Here I’ve ordered the wires per the T568B standard:
Flatten and compress the wires while maintaining the correct wiring order. This trains the wires to stay in position for insertion into the RJ45 crimp connector plug:
The wires are ordered per the T568B standard, straitened and compressed. The first 1/2 inch of wires extending beyond the blue cable jacket are the important area because this is the section that will be inserted into the RJ45 plug crimp connector:
Measure and Cut the Wires to Fit the Plug
The wires need to be cut to fit the RJ45 plug. The wire length doesn’t need to be exact – I just eyeball it. What is important is the blue insulation jacket extends past the crimp connector strain relief crush tab (see the next 3 photos):
Cut the wires to length using the crimp tool cutter. Make an even cut so the wire ends are all the same length:
Insert the Ethernet Cable into the RJ45 Plug
Verify the wires are still in the correct order and flat, orient the plug with the latching tab facing away from you, then push the cable and wires into the RJ45 crimp connector plug. The wires should slip in smoothly and be fully seated. Internal guides in the crimp connector will ensure the wires go in straight:
Before crimping, verify the wires are in the correct order (per T568B in my case):
Final check before crimping:
- The blue insulation jacket extends well past the strain relief tab.
- All wires are fully seated in the plug.
Place the RJ45 plug in the crimp tool slot marked “8P” (for 8 Position) and squeeze the jaws until fully closed to crimp the plug on the cable:
The crimped-on RJ45 plug:
- Metal contacts have pierced the wire insulation.
- Strain relief tab is holding the cable firmly in place.
The completed RJ45 crimp connector plug:
Next wire the other cable end the same way.
Ethernet Cable Testing
If a patch cable doesn’t work I’ll swap it with a known-good cable to see if it’s the cable or a network misconfiguration problem. When it’s a cable problem I just cut off the RJ45 plug or jack and wire on a new one which usually fixes the it. A network cable tester can be very useful and save time by validating the wiring immediately or identify the specific wiring fault.
A cable tester only verifies the cable wiring but can’t tell you if it’s a network problem. The next step up is Layer 1 through 7 network connectivity testing (PoE, Port/Link, VLAN, DHCP, IP address and Internet/server connectivity) with a Fluke LinkSprinter Network Tester.
Thanks for reading,
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