| Cable Category |
Cat5e
Cat6
Cat6A
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Cat5e and higher categories support 1000BASE-T Ethernet and standard four-pair PoE when the complete channel is correctly installed. Cat6A provides better headroom for 10GBASE-T and high-noise environments.
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Use a cable category that meets or exceeds the network speed and the permanent-link requirements. Do not mix lower-category patch cords into a channel designed for higher performance.
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| Total Cable Length |
Keep the permanent link within 90 m and the complete channel within 100 m. |
Structured cabling commonly allows up to 90 m for the permanent link plus up to 10 m of patch cords, for a 100 m channel. Longer runs may require an approved extender, repeater, or fiber-and-power design.
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Measure the complete path, including patch panels, service loops, horizontal runs, and equipment cords. Greater length increases resistance and voltage drop, especially at higher PoE power levels.
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| PoE Power Class |
Select the cable and connectors for the required IEEE 802.3 power type.
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IEEE 802.3af Type 1: up to 15.4 W supplied by the PSE and 12.95 W available at the powered device. IEEE 802.3at Type 2: up to 30 W PSE and 25.5 W at the device. IEEE 802.3bt Type 3: up to 60 W PSE and 51 W at the device. IEEE 802.3bt Type 4: up to 90 W PSE and approximately 71 W at the device.
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Confirm the PSE output, powered-device input requirement, cable temperature rating, conductor size, and connector current rating. Higher-power PoE uses all four pairs.
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| Conductor Size |
Use solid copper conductors for permanent links; choose a suitable 23–24 AWG cable for longer or higher-power runs when permitted by the installation system. |
Larger copper conductors generally have lower DC resistance and produce less voltage drop and heating. Copper-clad aluminum is not equivalent to solid copper for standards-based structured PoE cabling.
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Check the manufacturer’s DC resistance, pair resistance unbalance, conductor material, and ampacity information. Avoid relying on AWG alone when evaluating bundle heating.
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| Shielding |
U/UTP for ordinary low-noise spaces
F/UTP or S/FTP for electromagnetic-noise areas
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U/UTP has no overall or pair shielding. F/UTP has an overall foil shield. S/FTP uses an overall braid with individually foil-shielded pairs. Shielding can reduce electromagnetic interference when correctly bonded.
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Use shielded cable only with compatible shielded jacks, plugs, patch panels, and proper bonding. Keep data cabling separated from high-voltage power cables and major sources of electrical noise.
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| Connector and Pinout |
Use an 8P8C modular connector commonly called RJ45, wired consistently to T568A or T568B. |
T568A and T568B both support Ethernet when the same wiring scheme is maintained across the link. PoE uses the twisted pairs and relies on the Ethernet interface’s defined power-detection and classification process.
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Match plug type to conductor construction: solid-conductor plugs are not interchangeable with stranded patch-cord plugs. Verify category rating, contact plating, cable diameter range, and latch clearance.
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| Cable Construction |
Use four-pair, 100-ohm balanced twisted-pair cable with appropriate separation and jacket construction. |
Standard PoE Ethernet requires all four twisted pairs for the higher-power IEEE 802.3bt types. Pair geometry and impedance control help preserve insertion loss, return loss, and crosstalk performance.
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Do not untwist pairs more than the termination instructions allow. Avoid excessive pulling force, tight staples, crushed sections, and sharp bends that can change cable performance.
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| Indoor or Outdoor Installation |
Indoor-rated cable for dry interior spaces; outdoor-rated, UV-resistant, and moisture-resistant cable for exposed routes.
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Indoor PVC or low-smoke, zero-halogen jackets are selected according to building and fire-code requirements. Outdoor cables may require UV resistance, water blocking, sunlight resistance, and suitable direct-burial or conduit approval.
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Confirm local fire, plenum, riser, conduit, grounding, and direct-burial requirements. Do not use an indoor-only jacket outdoors or in wet locations.
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| Temperature and PoE Bundling |
Select the cable for the expected ambient temperature and bundle size, with extra margin for higher-power PoE. |
PoE current produces heat in the conductors. The allowable bundle size and current limits depend on cable construction, conductor resistance, ambient temperature, and the applicable cabling standard or manufacturer specification.
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Check the cable’s operating-temperature range and bundle derating table. Keep bundles organized, avoid over-tight cable ties, and provide ventilation in enclosed pathways.
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| Bend Radius and Mechanical Stress |
Follow the cable manufacturer’s minimum bend radius; avoid sharp bends and repeated flexing of solid-core cable. |
The minimum bend radius varies by cable diameter, shielding, construction, and whether the cable is under tension. Exceeding it can damage geometry and reduce transmission performance.
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Maintain the specified radius at corners, patch panels, ceiling transitions, and equipment entries. Use flexible stranded patch cords where frequent movement is expected.
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| EMI and Separation |
Route Ethernet away from high-voltage, motor, fluorescent-light, and variable-frequency-drive wiring. |
Electromagnetic coupling increases with parallel routing distance and decreases with physical separation. Metallic pathways and shielded systems require correct bonding to be effective.
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Cross power cables at approximately 90 degrees where routes must intersect. Follow local electrical codes and the separation guidance for the specific pathway.
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| Testing and Acceptance |
Test the installed link before final commissioning. |
Permanent-link or channel certification can verify wire map, length, insertion loss, return loss, propagation delay, and crosstalk parameters. PoE-capable certification equipment can also assess PoE-related cabling parameters.
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Record cable category, length, test limit, date, labeling, and test result. Replace damaged connectors or failed links instead of compensating with unsupported PoE settings.
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| Safety and Compatibility |
Use standards-compliant active equipment and passive components rated for the intended PoE application. |
IEEE-compliant PoE uses detection and classification to help prevent power from being applied to incompatible devices. Passive power injectors may not provide the same protection or interoperability.
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Verify device compatibility, polarity requirements, power budget, grounding, and installation instructions. Never assume that every Ethernet port or passive injector supports the same PoE voltage or power level.
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