Telecommunications Craft Knowledge (Knowledge Assessment)
Domain 1: Telecommunications Craft Knowledge
This domain samples the factual base a telecom installer needs: cable types and color codes, installation limits from TIA-568 and NEC Article 800, grounding and bonding, separation from power, firestopping, and test-method selection. Questions often give a field condition and ask which rule or test applies.
Core rules
- Pinouts: T568A and T568B differ on pairs 2 and 3. T568B is 1 white/orange, 2 orange, 3 white/green, 4 blue, 5 white/blue, 6 green, 7 white/brown, 8 brown. Keep the same scheme at both ends for a straight-through cable.
- Distance: Horizontal UTP is limited to 90 m (295 ft) of permanent link plus 10 m (33 ft) of patch cords, for a 100 m channel. Category rating does not extend distance.
- Separation: Maintain at least 2 in (50 mm) from power conductors; cross at 90 degrees when unavoidable. Apply NEC 800.133 and the manufacturer's separation table.
- Grounding/bonding: Bond telecom infrastructure to the TMGB or TGB with a listed conductor; do not use a separate earth electrode as the sole telecom ground. Intersystem bonding termination follows NEC 250.94.
- Firestopping: Restore fire-rated walls and floors with a listed system per NEC 300.21 and 800.26.
Worked example
A designer proposes an 84 m permanent link, a 7 m equipment-room cord, and an 8 m work-area cord. Channel length is 84 + 7 + 8 = 99 m, so it passes the 100 m channel limit. If the permanent link were 92 m, it would fail the 90 m permanent-link limit before patch cords are counted. Reasoning: check the permanent link and the full channel separately, then count every cord.
Traps
- Counting only the permanent link and ignoring patch cords in the 100 m channel.
- Mixing T568A at one end and T568B at the other, then calling it straight-through.
- Treating a continuity tester as a certification tester; it will not report NEXT or attenuation.
- Grounding telecom to a nearby water pipe or isolated rod instead of the building grounding electrode system.
- Skipping firestopping in a rated wall because the penetration is small.