Valuable Resources

Having the right references on hand can make the difference between guessing and knowing. These are some things you might consider having on hand when working through power design, troubleshooting, or system planning to save time, prevent mistakes, and keep your work code compliant.

National Electrical Code (NEC) 

Updated every three years by the National Fire Protection Association (NFPA), the NEC is the foundation of electrical safety in the U.S. It must be locally adopted, so requirements can vary by jurisdiction. Understanding which version your facilities follow is essential for compliance, coordination, and safe design.

Common sections AV professionals should reference include:

• • Article 310 – Conductor ampacity and insulation types; see Table 310.16 for wire sizing.
  • Article 314 – Box fill requirements; Section 314.16 details conductor volume limits.
  • Chapter 9, Table 1 – Conduit fill limits; typically 40% for three or more conductors.
  • Article 725 – Power-limited and control circuits; defines separation from line-voltage wiring.
  • Articles 800, 820, 830 – Communication, coax, and fiber cabling requirements.
  • Article 408 – Panelboards and circuit organization; helpful for load balancing and labeling.

NEMA Standards: Why They Matter

This is one of the few places where Facilities and AV really need to speak the same language. NEMA codes define exactly what type of plug or receptacle you are working with. Once you understand them, it becomes much easier to specify outlets correctly.

• • The first number identifies the voltage system:
    • 5 means 125 volts (standard wall power)
    • 6 means 250 volts
    • L means locking type
  • The second number shows the amperage rating (15, 20, 30, etc.)
  • P means plug, R means receptacle

Common types in higher education spaces:

• • 5-15R – Standard 15-amp outlet, used in most classrooms and offices.
  • 5-20R – Standard 20-amp outlet, used in most commercial applications.
  • L5-20R – Locking 20-amp, 125 volts. Useful for mobile racks or carts that move often and need a secure connection.
  • L6-20R – Locking 20-amp, 250 volts. Used for high-power equipment or specific lab devices.

Most classroom circuits are 20-amp branch circuits, even when the outlets are 5-15R. That is allowed by code because 15-amp receptacles are permitted on 20-amp branch circuits if there is more than one outlet on the circuit. These are the typical classroom runs that power projectors, control processors, and small equipment racks.

Branch circuits vs. dedicated circuits

A branch circuit is a shared run that feeds multiple outlets or devices in an area. In classrooms, a 20-amp branch circuit with 5-15R receptacles is the standard setup and is perfectly acceptable for typical AV loads such as DSPs, projectors, and small displays.

A dedicated circuit is reserved for a single outlet or device. These are used for larger racks, amplifiers, or any equipment that should not share power with other loads. Dedicated circuits are often 20 amp and may use 5-20R, L5-20R, or L6-20R receptacles depending on the connected equipment.

Dedicated circuits help isolate sensitive systems and prevent nuisance trips caused by vacuums or space heaters on shared lines. Always confirm circuit amperage, wire gauge, and breaker rating before specifying or installing a receptacle. Never assume that upsizing a receptacle automatically provides more power—it only works safely if the entire circuit is rated for it.

BICSI Codebook 

Often overlooked in AV, the BICSI Codebook provides detailed standards for low-voltage and structured cabling design. As PoE and networked AV continue to expand, these standards matter more than ever. BICSI defines proper separation between power and data, bonding and grounding requirements, and best practices for rack and pathway design. Following BICSI guidelines ensures cleaner installs, fewer cross-interference issues, and better long-term reliability across connected systems.

Ugly’s Electrical Reference

There are several versions of Ugly’s out there—everything from general electrical work to specialty editions for construction, motors, and even OSHA. For most AV professionals, though, the standard Ugly’s Electrical Reference will cover everything you’ll ever need from the NEC. It condenses the essentials into quick-reference tables for conductor ampacity, voltage drop, Ohm’s Law, and conversion formulas, making it easy to find the information that matters without flipping through hundreds of pages of code.

Mike Holt’s Website and App

Mike Holt’s resources are the perfect blend of accessibility and depth. His website and mobile app break down complex electrical topics through diagrams, calculators, and short videos that make the code practical. It’s a great place to learn or refresh concepts like grounding, bonding, or circuit protection. It’s also one of the best tools for training student workers or new AV technicians who need to bridge the gap between “plug it in” and understanding why it works.