
Electrical Load Calculation Validator
Validate electrical load calculations and NEC compliance before permit submission
What You Can Do
This skill performs comprehensive validation of your electrical load calculations against current NEC code requirements and project specifications. You get systematic review of lighting loads, motor calculations, HVAC equipment demands, branch circuit sizing, main service entrance sizing, and demand factor applications—identifying compliance gaps, coordination conflicts with mechanical/structural systems, and common calculation errors before design submission or permitting.
Features
verifies correct demand factor application across lighting, receptacles, and equipment loads
confirms proper starting current calculations and circuit protection sizing per NEC Articles 430 and 440
validates main service capacity, feeder sizing, and coordination with utility requirements
checks conductor sizing, overcurrent protection, and voltage drop compliance for all branch circuits
identifies conflicts between electrical loads and mechanical/structural equipment placement and feed locations
flags deviations from current NEC edition with specific article and section references
spots arithmetic mistakes, unit conversion errors, and incomplete load accounting
ensures proper application of lighting diversity and equipment diversity factors per design phase
Example Output
Example 1: Service Entrance Validation
- Input: 45,000 sq ft office building with proposed 400A service
- Output: ✓ Lighting load: 4.5 VA/sq ft × 45,000 = 202.5 kVA (demand factor 0.75 = 151.9 kVA) ✓ HVAC: 85 kVA at 1.0 demand factor ✓ Equipment loads: 22 kVA ⚠ Issue Found: Total demand 258.9 kVA exceeds 400A @ 208V (52 kVA). Recommend 600A service or equipment reassessment
Example 2: Motor Circuit Review
- Input: 10 HP 3-phase motor, 480V circuit sizing
- Output: ✓ Nameplate FLA: 14 A ✓ Circuit protection: 14 A × 2.5 = 35A breaker (NEC 430.52) ✓ ✓ Conductor: #8 AWG copper (40A rating) ✓ ⚠ Coordination Issue: Motor starter location 150 ft from panel—voltage drop on #8 = 2.8%. Consider #6 AWG to maintain 2% drop
What's Included
- SKILL.md instruction file with full validation methodology and code reference framework:
- NEC Load Calculation Checklist: itemized verification steps for all load categories
- Demand Factor Reference Table: current NEC Article 220 demand factors by load type and building occupancy
- Service Entrance Sizing Worksheet: step-by-step calculation template with automatic demand factor application
- Coordination Issues Template: structured format for documenting MEP conflicts and recommended resolutions
Who It's For
- MEP electrical engineers — validating load calculations before permit or client submission
- Junior electrical designers — learning proper NEC-compliant calculation methodology with mentor review
- Permit expeditors — preparing documentation packages and responding to plan review comments
- Electrical contractors — reviewing designs for constructability and confirming equipment specifications
- Building code officials — verifying compliance during plan review phase
Best For
- Reviewing completed load calculations for design documents and permit packages
- Validating service entrance and main feeder sizing against NEC Article 220 demand factors
- Motor circuit protection and conductor sizing verification per NEC Article 430
- Identifying MEP coordination conflicts between electrical loads and mechanical/structural equipment
- Teaching junior staff proper calculation methodology and code compliance procedures
- Troubleshooting why calculated loads don't match standard equipment available sizes
- Preparing for Value Engineering discussions with evidence of code-compliant alternatives







