Why do we need Permit Guidelines?
Variations in compliance requirements, some are insufficient to protect the public, others may not be consistent with established standards. Need a predictable process with uniform
enforcement of code requirements for jurisdictional authorities and installing contractors.
What are the objectives of the guidelines?
Facilitate the installation of safe systems at a minimum of cost.
Provide guidance on what information should be provided for permitting.
Discourage “fly-by-nights” from the industry by making them do all the steps that a good installer does.
Raise the professionalism of installing contractors.
What is the basic approach used to develop the guidelines?
Originally based on the 2002 NEC, Article 690, and various guidelines from a few jurisdictions and using input from several experienced professionals including installers and inspectors throughout the U.S. It has since been updated for the 2005 National Electrical Code.
In addition to national experts, California has over 45,000 systems that have been inspected by local jurisdictions. This is an experience base not previously available.
Approach is to establish a set of best practices that will help ensure that the public safety is preserved when an installation meets these guidelines.
Who will benefit from these guidelines?
Jurisdictions in charge of public safety in the built environment (authority having jurisdiction or AHJ).
Plan checkers and field inspectors tasked with reviewing PV systems.
Installers who need consistent criteria in which to have their systems reviewed.
Definitions: PV Cell
Cell: The basic photovoltaic device that is the building block for PV modules.
Connect Cells To Make Modules
One silicon solar cell produces 0.5 volt
36 cells connected together have enough voltage to charge 12 volt batteries and run pumps and motors
72-cell modules are the new standard for grid connected systems having a nominal voltage of 24-Volts and operating at about 30 Volts.
Module is the basic building block of systems
Can connect modules together to get any
Power configuration PV Performance Parameters
Open-circuit voltage (Voc)
Short-circuit current (Isc)
Maximum power voltage (Vmp)
Maximum power current (Imp)
Maximum power (Pmp)
Definitions: PV Module
Module: A group of PV cells connected in series and/or parallel and encapsulated in an environmentally protective laminate.
Definitions: PV Panel
Panel: A structural group of modules that is the basic building block of a PV array.
Definitions: PV Array
Array: A group of panels that comprises the complete direct current PV generating unit.
Definitions: Balance of System (BOS)
BOS: The balance of the equipment necessary to integrate the PV array with the site load (building). This includes the array circuit wiring, fusing, disconnects, and power processing equipment (inverter).
Differences Between PV and Conventional Electrical Systems
PV systems have dc circuits that require special design and equipment.
PV systems can have multiple energy sources, and special disconnects are required to isolate components.
Energy flows in PV systems may be bi-directional.
Utility-Interactive PV systems require an interface with the ac utility-grid and special considerations must be adopted. (utility must be involved-hence utility training)
PV System Electrical Design: Common Problem Areas
Insufficient conductor capacity and insulation
Excessive voltage drop
Unsafe wiring methods
Lack of or improper placement of over current protection and disconnect devices
Use of unlisted, or improper application of listed equipment (e.g. ac in dc use)
Lack of or improper equipment or system grounding
Unsafe installation and use of batteries
Download Inspection manual for solar installations
Excel Spreadsheet to calculation of battery size and number thereof from the details of PV panels
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