CITY & COUNTY OF DENVER
COMMUNITY PLANNING & DEVELOPMENT
BUILDING PERMIT POLICY
Subject:
SOLAR ENERGY SYSTEM PERMITS
Approved:
Michael Roach, P.E., Building Official
Number:
IRC M2301
Reference:
Issued Date:
Revised:
November 2, 2004
October 17, 2011
Page:
1 of 3
DBC Section 131 and IRC Section M2301, NEC Article 690
The procedure to obtain a permit for a solar system is as follows:
1. Obtain Zoning approval.
2. Name of system manufacturer, model name or number of system.
3. Details showing mounting of panels. Engineer’s design required when panels are not
flush mounted on roof. Calculations performed by a Colorado registered professional
engineer shall be submitted to the Division to substantiate that the structure can support
the design loads specified in Chapter 16 of the IBC and DBC. Details and calculations
for the panel connections to the roof shall be included.
4. A ladder must be provided at the time of the inspection for all roof mounted installations.
SOLAR HOT WATER PANEL SYSTEMS POLICY
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Piping diagram of system.
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Name of testing agency and approval number for the system.
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When the homeowner is the applicant for the permit, the permit process shall follow the
procedures outlined in DBC Section 131.3, and Policy 131.3.
SOLAR PHOTOVOLTAIC SYSTEMS POLICY
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•
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A professional engineer’s seal and signature will be required for all PV installations which
are not single family dwellings.
A professional engineer’s seal and signature will not be required for single family dwelling
unit PV installations unless the proposed PV system exceeds a solar maximum output of
10 Kilowatts or includes provisions for generator or battery backup.
For single-family residential installations, a flat valuation of $5000 will be assessed. The
actual valuation for commercial installations will be based upon the actual valuation. Per
State law, a maximum permit fee of $500 for residential and $1000 for commercial PV
Systems will be charged.
The design package to be submitted at the time of permit application must include two complete
sets of the following:
1. Manufacturer’s cut sheet and listing information for PV equipment, inverters and other
special equipment.
2. One Line Diagram: Indicate all conductor sizes and insulation types, conduit sizes, fuse
and circuit breaker ratings, inverter ratings, GFPD, ac and dc disconnect ratings. Specify
the PV module’s nameplate short circuit current and open circuit voltage. If disconnects,
breakers, fuses, GFPD, etc. are part of a larger piece of equipment, show them as such,
CITY & COUNTY OF DENVER
COMMUNITY PLANNING & DEVELOPMENT
BUILDING PERMIT POLICY
Subject:
SOLAR ENERGY SYSTEM PERMITS
Approved:
Michael Roach, P.E., Building Official
Number:
IRC M2301
Issued Date:
Revised:
November 2, 2004
October 17, 2011
Page:
2 of 3
showing how they are connected to the other devices and indicating their ratings. The
inverter must be shown as either connected to a dedicated branch circuit with back-fed
overcurrent protection (NEC 705.12(D)(5)) or connected to the supply side of the service
disconnecting means (NEC 705.12(A)). The AC and DC grounding electrode conductors
must be shown on the one-line diagram (NEC 690.41).
3. Calculations: Submit conductor ampacity calculations based upon 156% multiplied by the
short circuit current (NEC 690.8). Also include the temperature derating correction factor
per NEC Table 690.31(C). For all roof mounted wiring, use a worst case ambient
temperature of 61-70 degrees C (141-158 degrees F). The DC breakers or fuses must
be sized in 1 amp increments up to 15 amps per NEC 690.9(C). Provide calculations
showing that the total rating of overcurrent devices supplying power to the AC load center
is less than 120% of the load-center rating (NEC 705.12(D)(2).
4. Show by calculations that the maximum PV system voltage is less than the maximum
rated DC inverter input voltage and less than the voltage rating of all connected
equipment (NEC 690.7).
5. The maximum PV system voltage is equal to the open circuit voltage multiplied by the
number of modules in series multiplied by the NEC derating correction factor from Table
690.7 for the -21 to -25 degrees C (-5 to -13 degrees F) range.
6. Provide calculations indicating that the equipment grounding conductor is sized correctly
(NEC 690.43 & 690.45).
OTHER POINTS TO INCORPORATE INTO DESIGN:
1. Switches, fuses and breakers on the DC side of the system must be listed and labeled for
the DC voltage rating per NEC 690.9(D). Do not use “AC only” rated devices on the DC
side of the system.
2. If tied to grid, the inverter must be listed as utility-interactive (NEC 690.60).
3. Overcurrent protection is required where circuits are connected to more than one
electrical source (NEC 690.9).
4. The PV disconnecting means shall be installed at a readily accessible location either on
the outside the building or structure or inside nearest the point of entrance of the system
conductors (NEC 690.14(C)(1)).
5. No more than six PV system disconnecting means or six circuit breakers mounted in a
single enclosure, switchboard, or in a group of separate enclosures are allowed per NEC
690.14(C)(4).
6. The PV system disconnecting means shall be grouped together (NEC 690.14(C)(5)).
CITY & COUNTY OF DENVER
COMMUNITY PLANNING & DEVELOPMENT
BUILDING PERMIT POLICY
Subject:
SOLAR ENERGY SYSTEM PERMITS
Approved:
Michael Roach, P.E., Building Official
Number:
IRC M2301
Issued Date:
Revised:
November 2, 2004
October 17, 2011
Page:
3 of 3
7. Disconnecting means shall be provided to disconnect a fuse from all sources of supply if
the fuse is energized from both directions (NEC 690.16). Such fuse shall be capable of
being disconnected independently of fuses in other PV source circuits.
8. PV DC source or output circuits of a utility-interactive listed inverter can be run inside a
building or structure only when contained in metal raceways, type MC metal-clad cable
that complies with NEC 250.118(10), or metal enclosures from the point of penetration of
the surface of the building or structure to the first readily accessible disconnecting means
(NEC 690.31(E)).
9. Where the PV system panels are installed at an angle to the slope of the roof, a third set
of elevation and roof plans will be required by the Zoning department.
END OF DOCUMENT