Module 2 — General Requirements (Articles 90, 100, 110)
Definitions • Listing/Labeling • Working Space • Equipment Marking
Need the actual NEC text?
Open NEC 2023 Free Access Viewer (NFPA.org)
Open NEC 2023 Free Access Viewer (NFPA.org)
Create/login to a free NFPA account. Use the tips below to jump straight to Articles 90, 100, and 110.
Learning Objectives
- Explain Article 90 purpose, scope, enforcement.
- Use Article 100 to clarify definitions.
- Apply key rules in Article 110: listing/labeling, terminations, clearances, identification.
- Prioritize manufacturer instructions when part of the listing.
Core Concepts & Field Application
Article 90 — Big Picture
Scope & enforcement baseline; the NEC is a minimum—jurisdictions may add amendments.
Article 100 — Definitions
Check here first for terms. Frequent exam/field terms:
- Accessible / Readily Accessible — “Readily” excludes tools/ladders.
- Grounded vs Equipment Grounding Conductors — different functions & IDs.
- Bonding — equalizes potential to clear faults fast.
Article 110 — Requirements for Installations
| Topic | What to Look For |
|---|---|
| Listing & Labeling | Install equipment per its listing/labeling; follow manufacturer instructions. |
| Working Space | Depth/width/height clearances; dedicated space; egress. |
| Terminations | Conductor temperature ratings vs terminal ratings; torque; strand class. |
| Mechanical Execution | Neat and workmanlike; protection from damage; proper fittings. |
| Identification | Grounded (white/gray), EGC (green/green-yellow), ungrounded (others). |
Field tip: The nameplate and instructions can limit OCPD, conductor size, and clearances beyond general rules.
Navigation Tips
- Fast path to 90: In the NFPA viewer, use the left TOC and click Article 90 → skim Purpose/Scope, then Arrangement.
- Definitions workflow (100): When a test/plan term is unclear, check Article 100 before assuming meaning.
- Working space (110): Bookmark the table/figure for clearances; inspectors cite this often.
- Listing > generic rule: If listed instructions specify something different (e.g., torque), follow the listing.
- Cross-check: After 110, verify if a special occupancy in Ch. 5–7 modifies your general rule.
Study Checklist
- Article 90 overview—know what’s covered and who enforces it.
- Article 100 definitions—flag terms you meet in drawings/specs.
- Article 110 working space & listing/labeling—apply before rough-in.
🔎 Practice Tool: Codebook Navigation
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Tip: Use this with your printed codebook — star the terms your student struggles with to revisit quickly.