Solar Photovoltaic Power. Overarching Objectives. How many questions? 9/16/2012. From plan review to Final Inspection

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1 Solar Photovoltaic Power From plan review to Final Inspection Overarching Objectives A understandable and predictable process for both the Installer and the Inspector. The installation of safe, efficient, and code compliant Photovoltaic systems. Minimum cost and effort for both the installer and the inspection authority. How many questions? 1

2 Application Information Basic items to be included on application (refer to the handout) A building permit is required for Photovoltaic (PV) installations. Structural Considerations An assessment of the current roof covering The type of racking to be installed and how it is fastened to the roof framing Weather protection of fasteners The additional weight of the solar modules average 38 pounds 2

3 Application Information #1- A basic site diagram detailing the location of the major components of the system. (refer to page 2 of the handout) AC and DC Disconnects Solar production meter and utility meter Main breaker panel Inverter 3

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5 One line diagram Major field installed components Wire types and sizes both AC and DC and Correction Factors (B)(2)(a)-number of wires in any given conduit Wiring Methods Methods Permitted. (A) Wiring Systems. All raceway and cable wiring methods included in this Code and other wiring systems and fittings specifically intended and identified for use on photovoltaic arrays shall be permitted. Fine Print Note FPN: Photovoltaic modules operate at elevated temperatures when exposed to high ambient temperatures and to bright sunlight. These temperatures may routinely exceed 70 C (158 F) in many locations. 5

6 Module Wiring in free air (B) Single-Conductor Cable. Types SE, UF, USE, and USE-2 single-conductor cable shall be permitted in photovoltaic source circuits. USE 2 is the standard for most rooftop free air wiring. Used to connect the end of the string to complete the DC circuit. Refer to the handout #2-Detailed module information STC= Standard test conditions Voc= Voltage open circuit Isc= Current short circuit #3-series/parallel configuration of modules. Appears in two locations 6

7 DC voltage in bright sun Refer to the handout #4-There are an number of different grounding requirements for PV systems Equipment grounding conductors AC and DC Grounding electrode conductors 7

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9 Electrical Requirements #5-Capacity of the existing electrical service (B) (1 through 4) (B)-Load side connection. Limited to 120% of the rating of the busbar or conductor and 2008 differ Refer to the handout Point of connection 9

10 Panelboard busbar capacity Electrical Details #6-Location of the inverters. They can be outdoors, indoors, or on the roof!!!! Many inverters are listed as weather tight If code rules are followed inverters can be in not readily accessible areas Micro Inverters are beginning to appear 10

11 Electrical Details #7-Total number of modules installed #7-Number of modules per string #8-Wiring configuration of modules When servicing the solar array it would be helpful to know how the series connections have been made. The example in the handout illustrates this. Electrical Requirements #9-Maximum voltage of any series string including cold weather factors. NEC Table Modules produce more voltage at cold ambient temperatures. The NEC charts include correction factors for determining the rating of equipment. See handout. Electrical Details #10-Operating current of parallel strings Article spells out the factors necessary for calculating current. These calculations should appear on permit submittals. There are separate factors to consider in this calculation. Taken together they equal 156 % 11

12 Sending that power out #11-Location of grid tie with connection details. In most of the systems you will see the connection will be made at a backfed circuit breaker (B)(5) contains the requirements for this backfed connection. Refer to the handout. Fuses and Breakers #12 Type and sizes of OC devices. Could be either fuses or breakers On the AC side of the inverter most of what you see will be familiar. The DC side of the system requires that OC devices be DC rated. 12

13 DC fuses locations #12 DC Rated Fuses Outside DC disconnect 13

14 34 Solar Modules on roof Handout details engineering assessment of a solar installation utilizing the above modules. In some localities no engineer required if manufactured racking system is used Age of building could enter into picture Commercial vs. residential Licensing of PV installers PV 1 and PV 2 E 1 and E 2 Now PV 2 license holders may not make the grid tie connection. Adds an additional level of angst for the inspector. Only 40 in state-ce is just beginning now Q & A 14

15 IQ Electrical Training says Thank You 15