Alaska Low Voltage Practice cheat sheet

Alaska electrical work is regulated under AS 08.40 (Electrical Administrators) and the Board of Electrical Examiners regulations in 12 AAC 32.

AS 18.60.060 adopts the National Electrical Code as the basis for Alaska electrical installation requirements, with state amendments in 8 AAC 70.

Alaska defines a low-voltage/limited-energy scope by NEC Article 725 energy limits rather than by a single statewide voltage number; verify project-specific limits in the adopted code edition.

Class 1 circuits are power-limited per NEC 725.21 (voltage and power thresholds); Class 2 and Class 3 circuits are defined by NEC Table 725.21 current/voltage limits.

Asbestos abatement and lead-safe renovation rules (18 AAC 31 / 8 AAC 61.600) apply before drilling or penetrating older building assemblies.

Permits and inspections: local municipalities (e.g., Anchorage, Fairbanks, Juneau) may require separate permits; state law does not preempt local inspection authority.

Electrical Administrators license (AS 08.40.200) is required to hold the qualifying position for an electrical contractor business; individual journeyman/installer licensing is separate.

Work on fire alarm systems requires compliance with AS 18.70.075 (fire safety) in addition to NEC Article 760 and NFPA 72.

OSHA 29 CFR 1910 Subpart S covers general industry electrical safety; 1926 Subpart K covers construction.

Approach boundaries per NFPA 70E: limited, restricted, and prohibited; arc flash boundary is where incident energy equals 1.2 cal/cm².

Lockout/tagout (1910.147) requires energy isolation, verification of de-energization, and a single lock per worker.

Assured equipment grounding conductor program (1926.404(b)(1)(ii)) allows cord-and-plug tools without GFCI if tested and logged.

GFCI protection is required for temporary receptacles on construction sites (1926.404(b)(1)(i)) unless an assured grounding program is used.

PPE category is selected from incident energy; Category 0 requires no arc-rated clothing, Categories 1–4 require increasing arc ratings (4, 8, 25, 40 cal/cm²).

Confined space entry (1910.146) requires atmospheric testing before entry and a permit unless the space is reclassified.

Ohm's Law: V = I × R; power P = V × I = I²R = V²/R.

Series: R_total = R1 + R2 + …; current is the same through all components.

Parallel: 1/R_total = 1/R1 + 1/R2 + …; voltage is the same across branches.

AC impedance Z = √(R² + (X_L − X_C)²); X_L = 2πfL, X_C = 1/(2πfC).

Voltage drop in a two-wire DC circuit: V_drop = 2 × I × R × L (L = one-way length).

Power factor = real power / apparent power (kW/kVA); loads below 1.0 increase current for the same real power.

Decibel: dB = 20 log10(V2/V1) for voltage; +6 dB ≈ doubling of voltage, +3 dB ≈ doubling of power.

Balanced 3-phase power: P = √3 × V_LL × I × PF.

TIA-568 defines twisted-pair and fiber cabling performance categories (Cat 5e, 6, 6A, 8) and channel limits (100 m for copper).

TIA-569 covers pathways and spaces; TIA-570 covers residential; TIA-606 covers administration/labeling; TIA-607 covers bonding and grounding.

Maximum horizontal cable length is 90 m permanent link plus 10 m of patch cords = 100 m channel.

Category 6A supports 10GBASE-T up to 100 m; Category 6 supports 10GBASE-T up to 55 m.

Fiber: OM3/OM4 multimode for short reach; OS2 single-mode for long haul; connector loss typically ≤ 0.75 dB per mated pair.

Separation from power: TIA-569 and NEC 800.133 require separation (typically 2 in. for unshielded, or use of a barrier) between communications and power conductors.

Bend radius: 4× cable OD for UTP during installation; 10× OD for fiber (or manufacturer spec).

T568A and T568B wiring pinouts differ in pairs 2 and 3; both ends must use the same standard for a straight-through cable.

Crossover cable swaps transmit and receive pairs; modern auto-MDIX ports often make crossover unnecessary.

PoE standards: 802.3af (15.4 W at PSE), 802.3at (30 W), 802.3bt (60 W or 90 W).

Ethernet pin usage: 10/100BASE-T uses pairs 1-2 and 3-6; 1000BASE-T uses all four pairs.

Cable test parameters: wire map, length, insertion loss, NEXT, PS-NEXT, return loss, and (Cat 6A) alien crosstalk.

Fiber connectors: LC (small form factor), SC (square), ST (bayonet); polish types PC, UPC, APC (APC uses 8° angled ferrule).

Demarcation point is where carrier responsibility ends; the smart jack/NID belongs to the carrier.

NFPA 72 governs installation, testing, and maintenance; NFPA 70 Article 760 governs fire alarm wiring.

NEC 760 distinguishes NPLFA (non-power-limited) and PLFA (power-limited) fire alarm circuits; PLFA cable must be listed for the purpose.

Class A circuits survive a single open; Class B circuits do not; Class X (newer) provides redundancy for addressable loops.

Smoke detector spacing: 30 ft (9.1 m) nominal on smooth ceilings, with 15 ft (4.6 m) to walls; check local amendments.

Notification appliance circuits (NACs) must maintain voltage within appliance listing at the last device; voltage drop calculation is required.

Initiating device circuits and NACs require end-of-line (EOL) resistors or supervised module termination.

Fire alarm control panel battery calculation must support 24 h standby plus 5 min alarm (or as required by the adopted code).

Record of completion (NFPA 72 Figure) is required at system acceptance.

Access control: reader → controller → door hardware; fail-safe locks unlock on power loss (life safety egress), fail-secure locks remain locked.

Request-to-exit (REX) devices and door position switches are required for code-compliant egress; NFPA 101 requires free egress without special knowledge.

Wiegand is a legacy 26-bit to 40-bit interface; OSDP is the modern bidirectional, encrypted reader-to-controller protocol.

CCTV: IP cameras use PoE; analog uses coax with baluns; lens FOV and pixel density determine identification distance.

Pixel density guidelines: ~40 px/ft for identification, ~80 px/ft for recognition; verify with camera manufacturer.

Balanced twisted pair (RS-485) is used for PTZ control and long-distance reader buses; keep away from dimmers and ballasts.

Grounding: CCTV and access control systems should use a single-point ground referenced to the building electrode system per TIA-607.

RS-485: differential, multi-drop, up to ~1200 m at low baud; 120 Ω termination at both ends of the bus.

BACnet: MS/TP runs over RS-485; BACnet/IP runs over Ethernet; object-oriented device model.

LonWorks uses a free-topology transceiver; TP/FT-10 at 78 kbps.

Modbus RTU over RS-485; Modbus TCP over Ethernet; register-based addressing.

Audio: 70V/100V constant-voltage distributed systems use transformers at each speaker; power tap selection sets SPL.

HDMI/HDBaseT: HDBaseT extends HDMI up to 100 m over Cat 6A; HDMI passive copper limited to ~5 m for 4K.

DMX512 for lighting control uses RS-485 physical layer at 250 kbps; 120 Ω termination required.

Continuity and wire-map tests verify pinout; TDR locates opens and length; OTDR characterizes fiber events.

Insulation resistance test (megohmmeter) at 500 V DC for low-voltage cable; reading should be in the hundreds of megohms or higher.

Fluke/LinkRunner-style certifiers report PASS/FAIL against TIA category limits; retain reports as documentation.

Troubleshooting sequence: verify power → verify termination → verify continuity → verify signal integrity → verify device configuration.

Voltage drop on long PoE runs: V_drop = 2 × I × R; if drop exceeds ~10% the PD may not power up reliably.

Ground loop symptoms: hum on audio, video rolling bars, intermittent data; remedy with isolation transformers or single-point ground.

Label both ends of every cable per TIA-606; unlabeled cable is the most common cause of maintenance delay.

This domain is not part of the exam blueprint; retained for structural completeness only.

No exam content is derived from this section.

Consult the nine primary domains above for authoritative content.

Cross-reference NEC Article 100 definitions for any ambiguous term.

Always verify code edition adopted by the AHJ.

Maintain as-built documentation for every installation.

Record test results at time of acceptance.