Wiring Ethernet Cables
 


Required:

  • Ethernet Cable - bulk Category (Cat) 5, 5e, 6, 6a or higher ethernet cable
  • Wire Cutters - to cut and strip the ethernet cable if necessary
  • For Patch Cables:
    • 8P8C Modular Connector Plugs ("RJ45")
    • Modular Connector Crimper ("RJ45")
  • For Fixed Wiring:
    • 8P8C Modular Connector Jacks ("RJ45")
    • 110 Punch Down Tool

Recommended:

  • Wire Stripper
  • Cable Tester

How to wire Ethernet Patch Cables:

  1. Strip off about 2 inches of the ethernet cable sheath.
  2. Untwist the pairs - don't untwist them beyond what you have exposed, the more untwisted cable you have the worse the problems you can run into.
  3. Align the colored wires according to the wiring diagrams above.
  4. Trim all the wires to the same length, about 1/2" to 3/4" left exposed from the sheath.
  5. Insert the wires into the RJ45 plug - make sure each wire is fully inserted to the front of the RJ45 plug and in the correct order. The sheath of the ethernet cable should extend into the plug by about 1/2" and will be held in place by the crimp.
  6. Crimp the RJ45 plug with the crimper tool.
  7. Verify the wires ended up the right order and that the wires extend to the front of the RJ45 plug and make good contact with the metal contacts in the RJ45 plug
  8. Cut the ethernet cable to length - make sure it is more than long enough for your needs.
  9. Repeat the above steps for the second RJ45 plug.

How to wire fixed Ethernet Cables:

  1. Run the full length of ethernet cable in place, from endpoint to endpoint, making sure to leave excess.
  2. At one end, cut the wire to length leaving enough length to work, but not too much excess.
  3. Strip off about 2 inches of the ethernet cable sheath.
  4. Align each of the colored wires according to the layout of the jack.
  5. Use the punch down tool to insert each wire into the jack.
  6. Repeat the above steps for the second RJ45 jack.

If an ethernet cable tester is available, use it to verify the proper connectivity of the cable. That should be it, if your ethernet cable doesn't turn out, look closely at each end and see if you can find the problem. Often a wire ended up in the wrong place or one of the wires is making no contact or poor contact. Also double check the color coding to verify it is correct. If you see a mistake or problem, cut the end off and start again. A ethernet cable tester is invaluable at identifying and highlighting these issues.

When sizing ethernet cables remember that an end to end connection should not extend more than 100m (~328ft). Try to minimize the ethernet cable length, the longer the cable becomes, the more it may affect performance. This is usually noticeable as a gradual decrease in speed and increase in latency.