Hawaii Low Voltage Practice flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Class 2 circuit

A circuit supplied by a listed Class 2 power source that limits energy to safe levels, typically 30 V or less and limited current, allowing installation without the physical protection required for power circuits.

Class 3 circuit

A circuit powered by a listed Class 3 source with higher permitted voltage and current than Class 2 (up to 100 V and greater power). It still requires separation from power conductors but can support more devices.

Article 725 scope

NEC Article 725 governs Class 1, Class 2, and Class 3 remote-control, signaling, and power-limited circuits. It defines wiring methods, separation, and overcurrent protection for low-voltage control and signaling systems.

Article 800 scope

NEC Article 800 covers communication circuits, including telephone, data, and broadband. It addresses cable listing, primary protectors, grounding, and separation from power conductors to prevent fire and shock hazards.

Article 820 scope

NEC Article 820 governs community antenna television (CATV) and radio distribution systems. It requires listed coaxial cable, primary protectors at building entry, and bonding to the grounding electrode system.

Power-limited source

A listed supply whose output is inherently limited in voltage and current (for example, a Class 2 transformer or a listed Class 2 power supply). The listing defines the maximum permitted circuit current.

Separation requirement

Class 2 and Class 3 cables must be separated from power conductors by at least 2 inches (50 mm) or by a continuous barrier, unless the cable is listed for the combination or installed in a raceway.

Primary protector

A device installed on communication or antenna cables at the building entrance that limits surge voltage to ground. It must be bonded to the grounding electrode system with a conductor sized per the applicable NEC table.

Grounding electrode system

The interconnected set of grounding electrodes (rod, water pipe, concrete-encased, ground ring) defined in NEC Article 250. Communication and CATV protectors must be bonded to this system.

Voltage drop formula

VD = 2 × L × I × R / 1000, where L is one-way length in feet, I is current in amperes, and R is conductor resistance in ohms per 1000 feet. The factor 2 accounts for the return path.

Three percent rule

A common design guideline limits voltage drop on a branch circuit to 3% of source voltage and total feeder plus branch drop to 5%. NEC recommends these values in informational notes.

Low-voltage definition

In Hawaii practice, low voltage generally refers to circuits at 50 V or less, covering Class 2/Class 3 signaling, control, and communication systems installed under NEC Articles 725, 800, and 820.

HRS Chapter 448E

Hawaii's electricians and plumbers licensing statute. It establishes license categories and authorizes the Department of Commerce and Consumer Affairs to regulate electrical work in the state.

DCCA PVL

The Hawaii Department of Commerce and Consumer Affairs, Professional and Vocational Licensing branch. It issues and renews electrician licenses and administers exams and continuing education requirements.

Journeyman electrician license

A Hawaii license allowing the holder to perform electrical work under the supervision of a supervising electrician. It requires documented experience and passing a state examination.

Supervising electrician license

A Hawaii license authorizing the holder to supervise electrical work and, in some cases, to contract for electrical work. It requires additional experience beyond journeyman and a state exam.

Permit requirement

Electrical permits are issued by the county building department (for example, Honolulu DPP or Hawaii County). Permits and inspections are required for most electrical work, including new circuits.

EMT support spacing

Electrical metallic tubing must be supported within 3 ft of boxes and at intervals not exceeding 10 ft, per NEC Table 358.30. Supports must be listed and securely fastened.

PVC support spacing

Rigid PVC conduit support spacing depends on trade size: 3 ft for 1/2 in through 1 in, 5 ft for 1 1/4 in through 2 in, per NEC Table 352.30.

Box support distance

Raceways and cables must be secured within 12 in (300 mm) of a box and supported within 12 in of the box unless the box is designed to support the wiring method.

Conductor ampacity

Ampacity is the maximum current a conductor can carry continuously without exceeding its temperature rating. It depends on conductor size, insulation type, ambient temperature, and number of current-carrying conductors.

Derating for bundling

When more than three current-carrying conductors share a raceway or cable, ampacity is reduced per NEC Table 310.15(C)(1). Four to six conductors are derated to 80% of table ampacity.

Ambient temperature correction

Conductor ampacity is adjusted for ambient temperature using NEC Table 310.15(B)(1). Higher ambient temperatures reduce ampacity; lower temperatures may allow a slight increase.

GFCI protection

Ground-fault circuit interrupter protection is required in specific locations (bathrooms, kitchens, outdoors, garages) per NEC 210.8. It trips at 4-6 mA of ground-fault current to prevent shock.

AFCI protection

Arc-fault circuit interrupter protection detects dangerous arcing and is required on 120 V branch circuits in dwelling units per NEC 210.12. It reduces the risk of electrical fires.

Bonding vs grounding

Grounding connects equipment to earth; bonding connects metal parts together to ensure equal potential. Both are required for safety and are defined in NEC Article 100.

Equipment grounding conductor

The conductor that provides a low-impedance path for fault current back to the source, enabling overcurrent devices to trip. It is green, green with yellow stripe, or bare copper.

Cable tray fill

Cable tray fill is limited by NEC Article 392. The sum of cable cross-sectional areas must not exceed the tray's permitted fill, and cables must be supported and secured per the article.

Class 1 circuit

A circuit that is not power-limited and operates at up to 600 V, typically for remote control or signaling. It requires wiring methods similar to power circuits and overcurrent protection per Article 725.

Listing and labeling

Equipment must be listed by a recognized testing laboratory (UL, ETL) and installed per its listing. Field modifications that void the listing are not permitted under NEC 110.3(B).

Working clearance

NEC 110.26 requires a minimum working space in front of electrical equipment, typically 3 ft deep and 30 in wide, to allow safe maintenance and operation.

Hawaii county inspection

Each county (Honolulu, Hawaii, Maui, Kauai) issues electrical permits and conducts inspections. Work must be inspected before being covered or energized, and final inspection closes the permit.