Electrical drawing review checklist
A NEC-aligned review checklist for commercial electrical construction drawings
Electrical Drawings Reviewed
- Cover, code summary, and symbol legend (E-000 series)
- Site electrical plan and utility coordination
- Single-line diagram
- Panel schedules
- Lighting plans and controls
- Power plans
- Fire alarm plans (separate or with electrical)
- Low voltage / telecom plans (may be separate)
- Riser diagrams for power, fire alarm, telecom
- Details for grounding, equipment pads, equipment supports
- Specifications Division 26 (Electrical)
Service and Distribution
- Utility coordination form complete with utility company
- Service entrance conductor sizing matches load calculation
- Service short-circuit current rating documented and supported
- Service entrance equipment AIC rating exceeds available fault current
- Main disconnect properly identified
- Service grounding electrode system shown and detailed
- Bonding jumper sized per NEC 250
- Generator sizing and connection (if applicable) coordinated with transfer switch
Panelboards and Branch Circuits
- Panel schedules complete with circuit descriptions, loads, and totals
- Panelboard AIC rating exceeds available fault current at that location
- Spare circuit capacity per design intent (typically 20 to 25%)
- Demand factors applied per NEC Article 220
- Voltage drop within design limit (typically 3% branch, 5% total)
- Branch circuit conductor sizing per ampacity tables and load
- Overcurrent protection sized per conductor ampacity
- GFCI protection in required locations (NEC 210.8)
- AFCI protection in required locations (NEC 210.12)
- Tamper-resistant receptacles where required
Working Clearances and Access
- NEC 110.26 working clearance at every panel, switchboard, transformer
- 30" minimum width and 36" minimum depth at panel
- 6.5' minimum height clear of obstructions in working space
- Dedicated electrical space above panels per NEC 110.26(E)
- No piping, ductwork, or foreign systems in dedicated space
- Egress from electrical rooms per NEC 110.26(C)
Grounding and Bonding
- Grounding electrode conductor sizing per NEC 250.66
- Equipment grounding conductor sizing per NEC 250.122
- Bonding of structural steel, metallic water, gas, and CSST
- Separately derived systems grounded and bonded
- Special equipment grounding (data centers, IT spaces, healthcare)
Lighting and Controls
- Lighting power density within IECC / ASHRAE 90.1 limits
- Occupancy sensors in required spaces (private offices, conference rooms, restrooms)
- Daylight responsive controls in required daylight zones
- Automatic time-of-day shutoff or scheduling
- Manual switching available for all spaces
- Emergency lighting circuits properly separated from normal circuits
- Emergency egress illumination per IBC 1008
- Exit sign locations coordinated with life-safety plan
Emergency and Standby Power
- Emergency loads (NEC Article 700) identified and on dedicated branch
- Legally required standby loads (Article 701) identified
- Optional standby loads (Article 702) separated from emergency
- Transfer switches sized and coordinated with normal and alternate sources
- Generator fuel storage and run time meet code minimum
- Annunciator location accessible per code
Reviewer Tip
Always cross-check the panel schedule against the actual circuited devices on the power and lighting plans. Phantom circuits (on the panel schedule but not on the plan) and orphan devices (on the plan but not on a panel) are the two most common electrical drawing errors.
Coordination With Other Disciplines
- Mechanical equipment connections match mechanical schedule
- Plumbing equipment connections match plumbing schedule
- Fire alarm devices coordinated with fire protection
- Lighting locations coordinated with reflected ceiling plan
- Panel locations coordinated with architectural elevations
- Conduit routes coordinated with structural openings
Keep exploring
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