California Low Voltage Practice flashcards

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

NFPA 70E

Standard for Electrical Safety in the Workplace, covering arc flash risk assessment, PPE selection, and safe work practices for electrical workers.

Class 2 circuit

A circuit limited to 100 VA and 30 V RMS, typically used for low-voltage control and signaling, and exempt from many Chapter 3 wiring requirements.

NEC Article 725

The National Electrical Code article governing Class 1, Class 2, and Class 3 remote-control, signaling, and power-limited circuits, including cable and conductor requirements.

Plenum-rated cable

Cable marked CMP that has low smoke and flame spread characteristics and is approved for installation in air-handling spaces without conduit.

Conduit fill 40 percent

The maximum cross-sectional area of three or more conductors or cables allowed in a conduit, per NEC Chapter 9, Table 1.

Horizontal cable limit

TIA-568 specifies a maximum of 90 meters (295 feet) of horizontal cable plus 10 meters (33 feet) of patch cords for a 100-meter channel.

TIA-606 labeling

The standard requiring unique, machine-printed identifiers for cables, termination points, and patch panel ports to ensure accurate administration of cabling infrastructure.

Fiber loss budget

The sum of connector losses, splice losses, and fiber attenuation over a link, used to verify that the link will operate within the receiver sensitivity.

Smoke detector spacing

NFPA 72 requires detectors spaced no more than 30 feet apart on smooth ceilings, 15 feet from walls, and adjusted for ceiling height.

NAC appliance rating

Notification appliances must produce 15 dBA above ambient or 5 dBA above a maximum 105 dBA, whichever is greater, measured at 10 feet.

Class A circuit

A fire alarm circuit that continues to operate during a single open or ground fault, as defined in NFPA 72 Chapter 12.

Fail-safe lock

An access control lock that unlocks when power is removed, providing egress safety and typically used on perimeter doors.

PoE 802.3at

The IEEE standard for Power over Ethernet Plus, supplying up to 25.5 watts per port, used for PTZ cameras and access control readers.

OSDP protocol

Open Supervised Device Protocol, a secure encrypted communication standard for access control readers that replaces the older Wiegand interface.

70V speaker system

A constant-voltage distributed audio system using transformers to step up voltage, reducing line loss over long cable runs compared to 25V systems.

HDMI 2.1

A video interface standard supporting 48 Gbps bandwidth, 8K at 60 Hz, and 4K at 120 Hz, used for high-resolution AV distribution.

RS-485

A differential serial bus standard supporting up to 32 unit loads and 1,200 meters at lower baud rates, commonly used for control systems.

Ground rod minimum

NEC 250.52 requires a ground rod to be at least 8 feet long and 5/8 inch in diameter, and bonded to the building grounding electrode system.

SPD Type 1

A surge protective device installed at the service entrance, designed to handle high surge currents and protect downstream equipment.

Single-point ground

A grounding configuration for communications systems that bonds all equipment to one reference point to prevent ground loops and circulating currents.

Wire map test

A cabling certification test that verifies pin-to-pin connections, detects opens, shorts, crossed pairs, and split pairs in twisted-pair cable.

OTDR

Optical Time Domain Reflectometer, a test instrument that measures fiber loss and locates faults by analyzing backscattered light along the fiber.

As-built documentation

Final project records including cable schedules, panel schedules, test results, and device addresses, retained for the life of the system.

CSLB C-7 license

A California Contractors State License Board classification for low-voltage systems contractors, required for installation of communications and alarm wiring.

Title 24 Part 3

The California Electrical Code, adopted from the National Electrical Code with state amendments, governing electrical installations in California.

Ground resistance 25 ohms

NEC 250.53 requires a single ground rod to have a resistance of 25 ohms or less, or be supplemented by an additional electrode.

ACR

Attenuation-to-Crosstalk Ratio, calculated as insertion loss subtracted from near-end crosstalk in dB, indicating signal-to-noise margin in cabling.

Wiegand interface

A legacy access control communication protocol using two data wires and a ground, now being replaced by OSDP for security reasons.

TDR

Time Domain Reflectometer, a test instrument that locates faults in metallic cables by measuring the reflection time of a pulse and using velocity of propagation.

GFCI requirement

California OSHA Title 8 Section 2395 requires ground-fault circuit interrupter protection for temporary power and extension cords used outdoors or in wet locations.

FPLR cable

Fire alarm cable rated for riser installation, with flame-retardant characteristics suitable for vertical runs in a building, per NEC 760.

Bend radius four times

The minimum bend radius for 4-pair UTP cable during installation is four times the cable diameter; after installation it is one times the diameter.