PV Std Permit Instructions

8/17/2019 PV Std Permit Instructions

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Standard Permit Applicationfor Photovoltaic (PV) Systems

Residential, Roof-Mounted, Grid-Connected Installations

By the Permitting Subcommittee of SolarTech

Authors: Carl Mills, Sierra Club, Loma Prieta Chapter

Kurt Newick, Horizon Energy Systems

Eric Klem, REgrid Power

Scott Troyer, City of San Jose

David Varn, SolarTech

Contributors: John Wiles, New Mexico State University

Date: 7/29/08


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Standard Permit ApplicationResidential, Roof-Mounted, Grid-Connected PV Systems

Permitting Subcommittee of SolarTech Page 2 of 22 07/29/08

PURPOSE

The Permitting Subcommittee of SolarTech (PSS) proposes Form PV1 as a standard application for the permit to

install photovoltaic (PV) systems that meet the following criteria:

• Residential

• Roof mounted

• Grid connected

PSS bases its proposal on the conviction that standardization will make the permitting and inspection process easier

and faster for building departments and solar contractors, while preserving the highest standards for human andsystem safety.

INTRODUCTION

What is the Standard Permit Application (SPA) for PV Systems?

This SPA establishes minimum standards for uniform permitting of PV systems. It is based on applicable codes and

other standards, as well as on the practical experience of installers and inspectors throughout California. Adopting

these standards would streamline PV system permitting processes in building departments.

Why Is It Important?

Installation costs are almost 20 percent of the total costs of solar power in the U.S. today. In contrast, in Japan and

Germany installation costs are about 10 percent of the total. Since workers in both markets are comparably paid, this

advantage must be attributed to better building and installation standards. In the foreign markets, simplified

construction techniques, more effective standardization, and a highly trained workforce have substantially lowered

installation costs. Adopting this SPA would do likewise by harmonizing inspection practices across building

departments.

Building permit and utility interconnection costs in the U.S. are also a substantially higher proportion of total costs

than in Europe and Japan. Lower costs in the foreign markets have resulted from greater homogeneity in solar

system permitting and interconnection. The U.S. must streamline permitting and utility interconnection standards tolower solar installation costs. Adopting this SPA would achieve that by unifying permitting and interconnection

practices.

Who Will Benefit, and How?

• Installers will be better prepared for installation and inspection, and will achieve greater efficiency and a shorter learning curve. Excessive control will be avoided, and installations and inspections will become streamlined and

more predictable, thereby minimizing costs.

• Suppliers will be able to reduce variations in equipment. Effective standardization will promote a thrivingcomponent ecosystem, as the PC industry demonstrates.

• Consumers will benefit from reduced costs. They will also be assured safe and effective installations, with proper structural attachment, wiring and documentation.

• The PV industry as a whole will grow more rapidly and achieve a heightened image, further driving down costsand assuring long-term prosperity.


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Form PV1-INS Instructions—Standard Permit Application:Residential Grid-Connected PV Systems

09/27/2007, Version 2 Page 3 of 22 Permitting Subcommittee of SolarTech

HOW TO USE THIS DOCUMENT

PSS has organized its proposed application into two forms:

1. PV1 —A blank form that the PV system installer would complete to apply for the permit(s). Note California PVsystem installers should also complete the attached Application for PV System that contains information

required by the State of California. This form covers information about the installer (e.g. license class and

number) as opposed to the actual PV system.

2. PV1-INS —Elaborates on the values that the applicant would enter in Form PV1. Appendices A and B list (withsome examples) all the plans and cut-sheets the applicant might attach to Form PV1.

For ease of use, the sections in Form PV1-INS map exactly to the sections in Form PV1. For example, Section 1.1

in PV1-INS describes how to complete Section 1.1 in PV1.


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Form PV1-INS Instructions—Standard Permit Application:Residential, Roof-Mounted, Grid-Connected PV Systems

07/29/08 Page 4 of 22 Permitting Subcommittee of SolarTech

This form describes the values to enter in Form PV1: the Standard Permit Application for Residential Photovoltaic

(PV) Systems.

TABLE OF CONTENTS

1 Property Owner Information......................................................................................................................5

2 Site Plan........................................................................................................................................................5

3 Structural Information................................................................................................................................5

3.1 Roof Design...........................................................................................................................................................5

3.2 Wind Design..........................................................................................................................................................5

4 System Components ..................................................................................................................................6

5 Electrical Information.................................................................................................................................6

5.1 Array Electrical Specifications.............................................................................................................................6

5.2 Array Wiring and Calculations (DC)...................................................................................................................6

5.3 Source Circuits to Inverter Wiring and Overcurrent (DC)..................................................................................7

5.4 Inverter to Grid-Tie Wiring and Overcurrent (AC).............................................................................................7

5.5 Maximum System Voltage Calculations..............................................................................................................8

A Plans .............................................................................................................................................................9

A.1 Site Plan.................................................................................................................................................................9

A.2 Framing Plan .......................................................................................................................................................10

Span Table R802.5.1(1), .............................................................................................................................................10

Span Table R802.5.1(2), .............................................................................................................................................10

B Cut Sheets and Diagrams........................................................................................................................12

B.1 Roof-Mounting System.......................................................................................................................................12

Cut Sheet 1...................................................................................................................................................................12

Cut Sheet 2...................................................................................................................................................................13

Cut Sheet 3...................................................................................................................................................................14

Cut Sheet 4...................................................................................................................................................................15

Cut Sheet 5...................................................................................................................................................................16

B.2 PV Modules.........................................................................................................................................................17

Cut sheet page 1...........................................................................................................................................................17

Cut sheet page 2...........................................................................................................................................................18

B.3 Inverter ................................................................................................................................................................19

Cut sheet page 1...........................................................................................................................................................19

Cut sheet page 2...........................................................................................................................................................20

B.4 Wiring Diagram ..................................................................................................................................................21

C Application for a PV system form (information required by the State of California)......................22


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1 PROPERTY OWNER INFORMATION

Enter the contact information of the owner of the property where the PV system will be installed.

2 SITE PLAN

You are encouraged to attach a site plan showing the structure that supports the PV system and the system's location

on that structure (see Section A.1). The site plan must be on 8.5 x 11 or larger paper. This site diagram does notnecessarily have to be a to-scale drawing of the entire roof surface, as long as it clearly shows where on the roof the

solar panels will be located.

3 STRUCTURAL INFORMATION

3.1 Roof Design

The specifications in this section only apply to the part of the roof that supports the PV array.

1. Enter the weight (pounds) of the entire array assembly.

2. Enter the load concentration (pounds-per-square-foot, PSF), calculated as the array weight divided by the arrayarea.

3. Enter the dead load per support point (lbs.), calculated as the array weight divided by the number of supports.

4. Enter the type of roofing: e.g. composite shingles, wood shake, foam, cement tile, tar and gravel

5. Specify whether the roof construction uses rafters, trusses or some other form of manufactured roof joists andspecify the type of other. If a manufactured roofing system exists, skip to Section 3.2.

6. Enter the rafters' size (width x depth) in inches.

7. Indicate spacing between the rafters (e.g. 16 inches or 24 inches on center).

8. Enter the length of the longest unsupported span in feet and inches. When considering span lengths, you mustaccount for purlins. For example, list only the longest horizontal distance from the purlin to the adjacent point

of support (i.e. the wall or ridge).

9. Use a span table to determine if the rafters are over-spanned, then check the appropriate box. Section A.2includes the 2003 International Residential Code (IRC) span tables.

If the rafters are not overspanned, skip to Section 3.2.

If the rafters are overspanned, complete the remaining fields in the current section.

10. If the rafters are overspanned or the array is over 5 PSF, it is recommended that you provide one of thefollowing:a) A framing plan that shows details for how you will strengthen the rafters. b) Confirmation from a professional engineer that the roof structure will support the array.

3.2 Wind Design

1. If the PV system is building integrated (BIPV), check the Yes box and skip to Section 4. Otherwise, check theNo box and complete the remaining fields in this section.

2. Attach calculations or a cut sheet (see Section B.1) of the roof-mounting system that indicates it complies withthe required wind load level as specified in R301.2.1.4 (2) of the 2003 International Residential Code (IRC).

3. If the PV system is tilted over 18 inches above the roof, check the Yes box and complete the remaining fields inthis section. Otherwise, check the No box and skip to Section 4.

4. Enter the wind load (pounds-per-square-foot) for which the manufacturer of the roof-mounting system indicatesthe system is designed. This value is based on the site exposure, mounting height above ground and wind speed.


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Instructions—Standard Permit Application: Form PV1-INSResidential, Roof-Mounted, Grid-Connected PV Systems


5. Enter the total wind load on the array (pounds), calculated as the array area (square feet) multiplied by the windload (pounds-per-square-foot).

6. Enter the maximum uplift per support connection (pounds), calculated as the total wind load (pounds) on thearray divided by the number of supports.

4 S YSTEM COMPONENTS

For each type of component, indicate the number of units (where applicable), the manufacturer and model number.

For example:

1. Photovoltaic Modules: 18 Sharp Model NT-175U1 PV Modules

2. Inverter : 1 SMA Sunny Boy SB3000US (240V) Inverter

3. Roof-Mounting System: UniRac SolarMount components

4. AC Disconnect Switch: Not required

5. DC Disconnect Switch: Included with the inverter

6. Attach cut sheets for the PV modules (see Section B.2) and inverter(s) (see Section B.3). Attach cut sheets or adetail plan for the roof-mounting system (see Section B.1).

5 ELECTRICAL INFORMATION

1. Attach a wiring diagram for the PV system (see Section B.4).

2. Complete sections 5.1 through 5.5 for EACH inverter. If all the inverters have the same specifications, you needonly complete this information once.

Note: These instructions are not meant to be a technical design guideline manual explaining in detail how all

calculations were derived for these examples, much less all other possible scenarios for other PV system sizes in

various locations. Calculations are likely to vary significantly from what is shown in these examples for various PV

system sizes and for various locations. Please refer to the NEC manual for further information.

5.1 Array Electrical Specifications

Calculate the values based on PV module specifications.

1. Maximum Power Point Current (at STC) Produced by Array = (MPP module current) x (number of strings).STC refers to Standard Test Conditions and is a solar industry standard rating of maximum DC power for solar

modules.

2. Short Circuit Current Produced by Array = (module short circuit current) x (number of strings)

3. Maximum Power Point Voltage (at STC) Produced by Array = (MPP module voltage) x (number of modulesin string)

4. Open Circuit Voltage Produced by Array = (module open circuit voltage) x (number of modules in string)

5. STC Watts Produced by Array = (the peak capacity of the array in DC watts according to the Standard Test

Conditions rating) x (total number of modules)

6. PTC Watts Produced by Array = (the peak capacity of the array in AC watts according to the PV U.S.A. TestConditions rating) x (total number of modules) x (inverter efficiency as rated by the California EnergyCommission)

5.2 Array Wiring and Calculations (DC)

Enter values for the following parameters.

Note: Wire ampacities must be calculated using all NEC -required derating factors including, but not limited to:

temperatures of conductors and conduits in the environment, conduit fill, and any operating limits of the connected

equipment.


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1. Wire Type and Size = List the type and size (AWG) of the wire to be used under the solar modules on the roof.

Example: USE-2 / #10 AWG

2. Temperature Derated Ampacity of Wire = (base ampacity) x (temperature correction factor) X (conduit fillfactor)

Example: Four wires using #10 AWG USE-2 in free air.

Wire Ampacity = 55A (base ampacity from 900 C column in Table 310.17 for #10 AWG wire) X 0.41

(temperature derate correction factor for 800 C ambient temperature from 900 C column in Table 310.17) =

22.55A

Note 1: Base Ampacity and Temperature Correction Factor are found in NEC Table 310.16 (wires in conduit)

and Table 310.17 (wires in free air).

Note 2: Temperature Correction Factor for this example is derived from NEC 690.31(A) Fine Print Note which

mentions temperatures may exceed 700 C when exposed to high ambient temperatures and bright sunlight. Thus

800 C is used for this example.

Note 3: Conduit fill factor is found in NEC Table 310.15(B)(2)(a). No conduit fill factor was used in this

example as wires are in free air.

3. NEC-Required Wire Ampacity = (module short circuit current) x (1.25 for maximum illumination) x (1.25 for continuous duty)

Example: 5.4A (short circuit current for Sharp NT-175U1 solar module) X 1.25 X 1.25 = 8.4A

4. Equipment-Grounding Conductor Size = List the wire size to be used. You can obtain the minimum size from NEC Table 250.122.

5.3 Source Circuits to Inverter Wiring and Overcurrent (DC)

This is the wiring inside the conduit that goes from the array, or from a combiner box if one is present, to the

inverter.

1. Number of Wires, Type and Size = List the number of wires, type and size (AWG) of the wire to be used.

Example: Four USE-2 #10 AWG conductors in conduit

2. Temperature Derated Ampacity of Wire = [base ampacity of wire from NEC Table 310.16] x [temperaturederating from NEC Table 310.16] x [conduit fill factor derating from NEC Table 310.15(B)(2)(a)]. This is theactual wire ampacity, not the NEC-required ampacity.

Example: 30A (base ampacity from 600 C column in table 310.16) x 0.71 (temperature correction factor for 420

C ambient in table 310.16 for 600 C column) x 0.8 (conduit fill factor for 4 wires from table 310.15(B)(2)(a)) =17.04A

Note: The 600

C column for base ampacity is used in this example because wires attach to inverter which has a

600C maximum rating.

3. NEC-Required Wire Ampacity = (module short circuit current) x (number of strings per wire) x (1.56). This isthe NEC-required wire ampacity, not the actual ampacity.

Example: The Sharp NT-175U1 solar module short circuit current is 5.4A, thus the NEC -required wire

ampacity = (5.4A) x (1 string per wire) x (1.56) = 8.4A

4. Fuse Size (if applicable) = Fusing might be required if three or more strings are paralleled. List the fuse typeand size (amperes) if required.

5. Equipment-Grounding Conductor Size = List the wire size to be used. You can obtain the minimum size from NEC Table 250.122.

5.4 Inverter to Grid-Tie Wiring and Overcurrent (AC)

This is the wiring from the inverter to the grid-tie circuit breaker.


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1. Wire Type and Size = List the wire type and size (AWG).

2. Working Voltage = AC output voltage of inverter

3. Temperature Derated Ampacity of Wire = (base ampacity of wire from NEC Table 310.16) x (temperaturederating from NEC Table 310.16). This is the actual wire ampacity, not the NEC-required ampacity.

Example: 30A (base ampacity from 600 C column of Table 310.16) x 0.71 (temperature correction factor for 420

C ambient in table 310.16 for 600 C column) = 21.3A

Note 1: The 600 C column for base ampacity is used in this example because wires attach to inverter which has a

600 C maximum rating.

Note 2: The inverter is mounted in the shade under a patio cover for this example, thus 420 C ambient

temperature is used (this temperature represents the highest ambient temperature for this location. In somecases the highest ambient temperature can be found at the weather.com web site for a particular location).

Note 3: Two current carrying wires are used in this example, so no conduit fill factor is required to compute

wire ampacity, as Table 310.15(B)(2)(a) applies to conduits with more than three current carrying wires.

Note 4: Conduits in close proximity to rooftops exposed to direct sunlight may need to have 170 C added to

ambient temperature per NEC 310.10 FPN No. 2.

4. NEC-Required Wire Ampacity = (inverter manufacturer specified maximum output current) x (1.25 for continuous duty). This is the NEC-required wire ampacity, not the actual ampacity. See example in next item.

5. Overcurrent Protection (AC breakers) Size = The overcurrent protection (e.g., circuit breaker) size must beequal to or greater than the value entered in the preceding item: NEC -Required Wire Ampacity. It must also be

less than or equal to the temperature derated ampacity of the wire.

Example: If the SB3000US maximum output current is 12.5A, then (12.5A) x (1.25) = 15.63A, and since thereis no 15.63A breaker size, the next larger size breaker of 20A is specified in this example.

6. Equipment-Grounding Conductor Size = List the wire size (AWG) to be used. You can obtain the minimumsize from NEC Table 250.122.

5.5 Maximum System Voltage Calculations

Enter values for the following parameters.

1. Lowest Ambient Temperature for Site = You can obtain this value from historical records athttp://www.weather.com/.

2. Low Temperature Voltage Multiplier (per NEC ) = Obtain this number from NEC Table 690.7, VoltageCorrection Factors for Crystalline Silicon Modules.

3. Maximum Voltage (DC) Produced by Array (Voc) at STC = (module open circuit voltage) x (number of modules in string)

4. Maximum System Voltage (DC) at Low Temperature = (low temperature multiplier) x (maximum voltage produced by array). This value is the product of items 2 and 3 above. The value must be under 600 volts and

under the inverter's maximum DC voltage (DCV) rating.

Example: SB 3000US has a 500 VDC maximum. So (1.13 for -100C) x (44.4 VDC) x (9 modules) = 451.5VDC.

5. AC Grounding Electrode Conductor Size = List the wire size (AWG) used between the main panel ground buss and the ground rod or ufer ground.

6. DC Grounding Electrode Conductor Size = List the wire size (AWG) used between the inverter and theground rod or ufer ground.


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A PLANS

This appendix describes the plans you might attach to your application.

A.1 Site Plan

A site plan is recommended for all PV systems. The following is an example.


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A.2 Framing Plan

A framing plan is required only if the combined weight of the PV array exceeds 5 pounds per square foot or the

existing rafters are over-spanned. You can use the following 2003 International Residential Code (IRC) tables to

determine if the rafters are over-spanned.

Span Table R802.5.1(1),

Use this table for rafter spans that have conventional light-weight dead loads and do not have a ceiling attached.

10 PSF Dead LoadRoof live load = 20 psf, ceiling not attached to rafters, L/!=180

Rafter Size 2 x 4 2 x 6 2 x 8 2 x 10 2 x 12

Spacing(inches)

Species GradeThe measurements below are in feet-inches

(e.g. 9-10 = 9 feet, 10 inches).

16Douglas

Fir-larch

#2 or

better 9-10 14-4 18-2 22-3 25-9

16 Hem-fir #2 or

better 9-2 14-2 17-11 21-11 25-5

24Douglas

Fir-larch

#2 or

better 7-10 11-9 14-10 18-2 21-0

24 Hem-fir #2 or better

7-3 11-5 14-8 17-10 20-9

Use this table for rafter spans that have heavy dead loads and do not have a ceiling attached.

20 PSF Dead LoadRoof live load = 20 psf, ceiling not attached to rafters, L/!=180


Spacing(inches)

Species GradeThe measurements below are in feet-inches

(e.g. 9-10 = 9 feet, 10 inches).

16Douglas

Fir-larch

#2 or

better 8-6 12-5 15-9 19-3 22-4

16 Hem-fir #2 or

better 8-5 12-3 15-6 18-11 22-0

24Douglas

Fir-larch

#2 or

better 6-11 10-2 12-10 15-8 18-3

24 Hem-fir #2 or

better 6-10 10-0 12-8 15-6 17-11

Span Table R802.5.1(2),

Use this table for rafter spans with a ceiling attached and conventional light-weight dead loads.

10 PSF Dead LoadRoof live load = 20 psf, ceiling attached to rafters, L/!=240


Spacing(inches) Species Grade The measurements below are in feet-inches(e.g. 9-10 = 9 feet, 10 inches).

16Douglas

Fir-larch

#2 or

better 8-11 14-1 18-2 22-3 25-9

16 Hem-fir #2 or

better 8-4 13-1 17-3 21-11 25-5

24DouglasFir-larch

#2 or better

7-10 11-9 14-10 18-2 21-0

24 Hem-fir #2 or

better 7-3 11-5 14-8 17-10 20-9


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Use this table for rafter spans with a ceiling attached and where heavy dead loads exist.

20 PSF Dead LoadRoof live load = 20 psf, ceiling attached to rafters, L/!=240


Spacing(inches) Species Grade

The measurements below are in feet-inches

(e.g. 9-10 = 9 feet, 10 inches).

16Douglas

Fir-larch

#2 or

better 8-6 12-5 15-9 19-3 22-4

16 Hem-fir #2 or

better 8-4 12-3 15-6 18-11 22-0

24Douglas

Fir-larch

#2 or

better 6-11 10-2 12-10 15-8 18-3

24 Hem-fir #2 or

better 6-10 10-0 12-8 15-6 17-11

Use the conventional light-weight dead load table when the existing roofing materials are wood shake, wood

shingle, composition roofing or light-weight tile roofs. (The rationale for allowing these tables to be used is that the

installation of a PV system should be considered as part of the live load, since additional loading will not be added

to the section of the roof where a PV array is installed.)

Where heavy roofing systems exist (e.g. clay tile or heavy concrete tile roofs), use the 20 psf dead load tables.


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B CUT SHEETS AND DIAGRAMS

This appendix describes the cut sheets and diagrams you might attach to your application.

B.1 Roof-Mounting System

It is recommended that you attach cut sheets or other detailed information for your roof-mounting system. Thefollowing cut sheets are examples from a UniRac manual.

Cut Sheet 1


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Cut Sheet 2


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Cut Sheet 3


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Cut Sheet 5


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B.2 PV Modules

You must attach cut sheets for the PV modules. The following are examples.

Cut sheet page 1


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Cut sheet page 2


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B.3 Inverter

You must attach cut sheets for the inverter. If you have multiple inverters with different specifications, attach cut

sheets for each inverter. The following are examples for a single inverter.

Cut sheet page 1


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Cut sheet page 2


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B.4 Wiring Diagram

You must attach a wiring diagram for the PV system. The following is an example.


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C APPLICATION FOR A PV SYSTEM FORM (INFORMATION REQUIRED BY THESTATE OF CALIFORNIA)

PV Std Permit Instructions

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