LAN Cabling Guide

Ethernet Cable Categories

Category	Max Speed	Frequency	Max Distance	Shielding	Typical Use

Power over Ethernet (PoE) Standards

PoE delivers both power and data over a single Ethernet cable, eliminating the need for separate power supplies for devices like IP cameras, access points, and VoIP phones.

Standard	Name	Max Power	Voltage	Min Cable	Typical Devices

Cable Length & Signal Loss Calculator

Ethernet signals degrade over distance. This calculator estimates signal quality based on cable category and length.

Cable Category

Cable Length (meters)

Twisted Pair Color Coding

All Cat5e-Cat8 cables contain 4 twisted pairs (8 wires total). The color coding is standardized:

Pair	Pin Numbers	Primary Color	Secondary Color	Function
Pair 1	4-5	Blue	White-Blue	Reserved / PoE
Pair 2	1-2	Orange	White-Orange	TX+ / TX-
Pair 3	3-6	Green	White-Green	RX+ / RX-
Pair 4	7-8	Brown	White-Brown	Reserved / PoE

Installation Best Practices

Maintain twist up to the termination point: Untwist no more than 13mm (0.5 inch) of wire at the connector. Excessive untwisting causes crosstalk and signal degradation.
Avoid tight bends: Do not bend cables sharper than 4x the cable diameter for Cat5e/Cat6, or 8x for Cat6a/Cat7/Cat8. Tight bends damage the twisted pairs internally.
Separate from power lines: Run data cables at least 30cm (12 inch) away from electrical wiring to minimize electromagnetic interference (EMI).
Use proper cable management: Avoid over-tightening zip ties. Use Velcro straps instead. Crushed cables degrade performance.
Test after installation: Use a cable tester to verify all 8 wires are correctly terminated and check for continuity, shorts, and split pairs.
Choose the right category for your needs: Cat6 is sufficient for most homes. Cat6a for 10G over full distance. Cat8 only for short data center runs.
Shielded vs Unshielded (UTP vs STP): Use shielded cable in environments with high EMI (factories, near heavy machinery). UTP is fine for most office and home installations.
Fire code compliance: Use plenum-rated cable (CMP) for air ducts and riser-rated (CMR) for vertical runs. Check local building codes.

Frequently Asked Questions

What is the difference between Cat6 and Cat6a?

Cat6 supports 10 Gbps up to 37-55 meters, while Cat6a supports 10 Gbps at the full 100 meters. Cat6a also operates at 500 MHz (vs 250 MHz for Cat6) and has better alien crosstalk resistance due to tighter twists and additional shielding.

Can I use Cat8 cable for home internet?

Technically yes, but it is overkill. Cat8 is designed for data center switch-to-switch connections at 25/40 Gbps over short distances (30m). For home use, Cat6 or Cat6a is more than sufficient and much cheaper. Cat8 cables are also thicker and harder to terminate.

What is the maximum length of an Ethernet cable?

The IEEE 802.3 standard specifies 100 meters (328 feet) as the maximum channel length for all Ethernet cable categories from Cat5e to Cat8. This includes the patch cord from the device to the wall outlet, the horizontal cable run, and the patch cord at the switch end.

Do I need shielded (STP) or unshielded (UTP) cable?

For most home and office installations, UTP (Unshielded Twisted Pair) is sufficient. Shielded cable (STP/FTP/SFTP) is recommended in environments with high electromagnetic interference, such as near industrial equipment, motors, fluorescent lights, or heavy power lines.

Can PoE damage non-PoE devices?

No. IEEE 802.3 PoE standards include a detection handshake - the PoE switch sends a low-voltage probe first. If the connected device does not respond with the correct signature, power is not applied. Standard non-PoE devices are safe to connect to PoE ports.

What cable do I need for 10 Gigabit Ethernet?

Cat6 can carry 10 Gbps up to 37-55 meters (depending on crosstalk environment). For reliable 10 Gbps at full 100m distance, use Cat6a or higher. Cat7 and Cat8 also support 10 Gbps but at higher cost.