📘 Code Breakdown — Article 110: Requirements for Electrical Installations

General Requirements for Electrical Installations

From residential homes to industrial facilities, Article 110 lays the foundation for safe, code-compliant installations. It’s the starting point for inspectors — and the section where violations stack up fast if overlooked.

🔍 What It Covers:

NEC 110 outlines universal rules that apply to all electrical installations. It focuses on safety, proper use of equipment, and accessible, professional work — no matter the system type.

🔹 Key Sections You Should Know:

110.3 — Installation & Use
✔️ Equipment must be listed, labeled, and installed per manufacturer instructions.
✘ No improvising — the NEC enforces what’s on the label.

110.12 — Mechanical Execution of Work
✔️ Work must be neat and workmanlike.
✘ No loose wires, exposed splices, or sketchy boxes.

110.14 — Electrical Connections
🔩 Torque terminals to spec.
🔗 Use proper wire-rated connectors (Cu/Al).
🌡️ Match terminal temp ratings (60°C vs 75°C) to the conductor.

110.16 — Arc Flash Warnings
⚠️ Requires warning labels on service equipment ≥ 1200A.
💥 Reminds personnel of potential arc flash hazards.

110.21 — Field-Applied Labels
📛 Labels must be durable, legible, and suited for the environment.

110.26 — Working Space Around Panels
📏 Panel clearance matters. Minimums:

• Depth: 3 ft (standard up to 600V)

• Width: 30" or width of equipment

• Height: 6.5 ft
  🚪 Gear ≥ 1200A? You need exits on both sides.

110.27 — Guarding Live Parts
🛡️ Live parts must be protected — with barriers, covers, or dedicated rooms.

✅ Why It Matters On Site

• Most inspection fails trace back to Article 110.

• Common issues: mislabeled gear, poor torque, blocked panel access.

• 110.26 is critical — memorize it when laying out service rooms and switchgear.

🛠️ Pro Tip:

Start your layout with clearance in mind. Don’t let other trades box you in. Build your gear wall around 110.26 to avoid clearance conflicts later.

❓ Quick Code Quiz

Question:
What’s the required working space (depth) in front of a 480V panel?

A) 2 ft
B) 3 ft
C) 4 ft
D) Depends on the enclosure

🤔 Think About It:
Clearance protects workers and ensures access. The requirement varies by system voltage and what’s in front of the panel.

✅ Answer: B) 3 ft — For systems up to 600V, NEC 110.26(A)(1) requires at least 3 feet of depth clearance.