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City of Thornton (CO)

Colorado Authority Having Jurisdiction Solar permitting requirements
NEC Code Version2023
Fire Code Version2018 Building Code
SolarAPP+ StatusTargeted
Wet Stamps RequiredDigital Structural
Fire Setback Enforced1

Codes

NEC Code Version
2023
Fire Code Version
2018 Building Code
Code List

2024 INTERNATIONAL BUILDING CODE

2024 INTERNATIONAL RESIDENTIAL CODE

2024 INTERNATIONAL PLUMBING CODE

2024 INTERNATIONAL MECHANICAL CODE

2024 INTERNATIONAL FUEL GAS CODE

2024 INTERNATIONAL EXISTING BUILDING CODE

2024 INTERNATIONAL ENERGY CONSERVATION CODE

2024 INTERNATIONAL SWIMMING POOL AND SPA CODE

2024 INTERNATIONAL FIRE CODE

2023 NATIONAL ELECTRIC CODE

ASCE Code Specification
ASCE 7-16

SolarAPP+ & submittal

SolarAPP+ Status
Targeted
Any SolarAPP+ Restrictions
1
SolarAPP+ Restrictions
MPU,Derate
How Many Plansets Required
1
Revision Required
1
Rough Inspection
Footing inspection
New Planset Required For Module Swap
1

Stamps

Ee Stamp Required On SLD
No
Wet Stamps Required
Digital Structural
Structural Calculations Required
Yes
Stamp Location On Plans
Center
Date On Stamps
Expiration Date

Fire setbacks

Fire Setback Enforced
1
Setback Notes


Structural & loads

Wind Speed
110
Wind Notes
  • 80 mph basic wind speed
  • 110 ultimate three second gust
  • Exposure Category C
Snow Load
30
Reducible Snow Load Allowed
1
Max Attachment Spacing
96
Structural Notes
  • The letter must be uploaded as a separate file and not included in the plan set.
  • If structural upgrades are required, show all upgrade details on the PV installation plans.
Minimum Ground On Roof
#6

Electrical

AC Disconnect Required
Yes
Electrical Load Calcs Required
Derates
Allowed POI
Meter Adapter,PV Breaker,Line Side Taps,Load Side Taps
Panel Schedule Required
Partial Home Backup
Temperature Rating
90
De Rating Ampacity
0.96
BOS Restrictions
  • Do not place BOS above a window well

Battery / ESS

Unique Battery Placards Needed
0
ESS Notes

Standard

Separate ESS Disconnect Required
ESS Disconnect
ESS Elevation Detail Required
No

Plan set

Plan Set Requirements

Include

  • Mounting foot specification sheet
  • Flashing specification sheet
  • Include a plan review stamp area in the title block, placed in the same location on every sheet.
Cover Page


Roof Plan
  • Do not place BOS above a window well
Electrical Diagram
  • Breaker tie-ins in split bus panels are not allowed.
  • USE #6 GROUND FREE AIR OR #6 GROUND IN EMT CONDUIT FROM MODULES TO JB (free air preferred)
  • All projects with MPU's must have MSP & main breakers labeled as existing (E) if a sub-contractor is pulling the MPU permit and doing the work.
  • Thornton will not approve our PV plans that show the MSP & main breaker as new (N) until the MPU permit is pulled by the sub-contractor. Centerfed 120% allowed
Custom Placards Required
1
Non Standard Revision Requirements
  • Cloud all changes

Ground mount

Ground Mount Fencing Required
No
Ground Mount Notes

Soil Class: Clay

Ground Mount Requires Soil Sample
Soil Study
Compiled from public records, 2026. Requirements change with code cycles and local amendments. Verify with the City of Thornton (CO) building department before you rely on this, and treat it as a research head start, not a ruling. Getting quotes? Run them through the quote checker first.