AZ CR-67 Low Voltage Study Guide/ CR-67 Low Voltage
Communica on Systems exam concepts from NFPA 70
(NEC), NFPA 72, OSHA 29 CFR Part 1926, etc.
In low-voltage installa ons, what is the purpose of twisted-pair cables? - Ans To reduce EMI
What is the maximum allowable voltage for low-voltage systems according to the NEC? - Ans
91V
What is the minimum burial depth for direct-burial low-voltage cables. - Ans 12in
Which NEC ar cle covers Class 2 and Class 3 circuits? - Ans Ar cle 725
What is the primary advantage of using fiber op c cables in low-voltage systems? - Ans
Immunity to electromagne c interference
What is the most common type of insula on used for low-voltage indoor cables? - Ans PVC
What is the voltage limita on for Class 2 power-limited circuits? - Ans 30V
What is the main concern when running low-voltage cables parallel to electrical wiring? - Ans
Electromagne c Interference
What color is typically used for ground wires in low-voltage systems? - Ans Green
, When installing cables in a plenum space, what type of cable jacket is required? - Ans CMP
(Plenum-rated)
What is the primary func on of a transformer in a low-voltage system? - Ans Step down
voltage
Which cable type is best suited for long-distance low-voltage communica ons? - Ans Fiber
Op c
What type of tool is used to verify low-voltage connec vity? - Ans Tone generator and probe
What is the maximum bend radius allowed for low-voltage cables? - Ans 4 mes the cable
diameter
What is the primary purpose of a relay in low-voltage systems? - Ans Provide mechanical
switching
What is the maximum cable length for a CAT 6 Ethernet cable before requiring a signal booster
or switch? - Ans 328 feet
Which standard governs the installa on of structured cabling systems? - Ans ANSI/TIA-568
What is the most effec ve way to reduce EMI in communica on cabling? - Ans Use shielded
cables
What is the primary func on of a patch panel in a digital communica on system? - Ans To
provide centralized cable management
Communica on Systems exam concepts from NFPA 70
(NEC), NFPA 72, OSHA 29 CFR Part 1926, etc.
In low-voltage installa ons, what is the purpose of twisted-pair cables? - Ans To reduce EMI
What is the maximum allowable voltage for low-voltage systems according to the NEC? - Ans
91V
What is the minimum burial depth for direct-burial low-voltage cables. - Ans 12in
Which NEC ar cle covers Class 2 and Class 3 circuits? - Ans Ar cle 725
What is the primary advantage of using fiber op c cables in low-voltage systems? - Ans
Immunity to electromagne c interference
What is the most common type of insula on used for low-voltage indoor cables? - Ans PVC
What is the voltage limita on for Class 2 power-limited circuits? - Ans 30V
What is the main concern when running low-voltage cables parallel to electrical wiring? - Ans
Electromagne c Interference
What color is typically used for ground wires in low-voltage systems? - Ans Green
, When installing cables in a plenum space, what type of cable jacket is required? - Ans CMP
(Plenum-rated)
What is the primary func on of a transformer in a low-voltage system? - Ans Step down
voltage
Which cable type is best suited for long-distance low-voltage communica ons? - Ans Fiber
Op c
What type of tool is used to verify low-voltage connec vity? - Ans Tone generator and probe
What is the maximum bend radius allowed for low-voltage cables? - Ans 4 mes the cable
diameter
What is the primary purpose of a relay in low-voltage systems? - Ans Provide mechanical
switching
What is the maximum cable length for a CAT 6 Ethernet cable before requiring a signal booster
or switch? - Ans 328 feet
Which standard governs the installa on of structured cabling systems? - Ans ANSI/TIA-568
What is the most effec ve way to reduce EMI in communica on cabling? - Ans Use shielded
cables
What is the primary func on of a patch panel in a digital communica on system? - Ans To
provide centralized cable management
