3 Article 690 Explored
3 Article 690 Explored
3 Article 690 Explored
ARTICLE
690.2 Denitions.
Alternating-Current PV Module. A PV module unit consisting of solar cells, inverter, and components necessary to generate alternatingcurrent (ac) power when exposed to sunlight. Figure 6903 Figure 6901
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690.4
Figure 69023
Figure 69022
PV system conductors must be identied by separate color coding, marking tape, tagging, or other approved means and grouped as follows: (1) PV Source Circuits. Identied at points of termination, connection, and splices. (2) PV Output and Inverter Circuits. Identied at points of termination, connection, and splices. (3) Multiple Systems. Conductors of each system must be identied at termination, connection, and splice points. Figure 69023 Ex: Identication of different systems isnt required where conductor identication is evident by spacing or arrangement. (4) Grouping. Where the conductors of more than one PV system occupy the same junction box or raceway with removable cover, the ac and dc conductors of each system must be grouped together by cable ties and at intervals not to exceed 6 ft. Figure 69024 Figure 69024 Ex: Grouping isnt required if the PV circuit enters from a cable or raceway unique to the circuit that makes the grouping obvious. (C) Module Connection. Module connections must be arranged so that the removal of a module doesnt interrupt the grounded conductor to other PV source circuits. (D) Equipment. Equipment for PV systems such as inverters, photovoltaic modules, source-circuit combiners, and charge controllers must be identied and listed for the application. Figure 69025
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690.5
(F) Circuit Routing. PV source and output conductors must be routed along building structural members (beams, rafters, trusses, and columns) where the location of those structural members can be determined by observation. The location of PV source and output conductors imbedded in builtup, laminate, or membrane roong materials in areas not covered by PV modules and associated equipment must be clearly marked. (H) Multiple Inverters. Where multiple utility-interactive inverters are located remote from each other, a directory is required at each dc PV system disconnecting means, at each ac disconnecting means, and at the main service disconnecting means showing the location of all ac and dc PV system disconnecting means in the building/structure. Figure 69025 Authors Comment: Listing means that the equipment is in a list published by a testing laboratory acceptable to the authority having jurisdiction [Article 100]. (E) Qualified Persons. PV systems, associated wiring, and interconnections must be installed by a qualied person. Figure 69026 Ex: A directory isnt required where all PV system disconnecting means are grouped at the service disconnecting means.
Figure 69027
Figure 69026
(C) Labels and Markings. A warning label must be on the utilityinteractive inverter stating the following: Figure 69028
Note: A qualied person has the knowledge related to construction and operation of PV equipment and installations; along with safety training to recognize and avoid hazards to persons and property [Article 100].
WARNING ELECTRIC SHOCK HAZARDIF A GROUND FAULT IS INDICATED, NORMALLY GROUNDED CONDUCTORS MAY BE UNGROUNDED AND ENERGIZED
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Mike Holts Illustrated Guide to Understanding 2011 NEC Requirements for Solar Photovoltaic Systems
690.7
(B) Inverter Output Circuit. The output circuit conductors of an ac module are considered an Inverter Output Circuit as dened in 690.2. Figure 69030
Figure 69028
Figure 69029
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690.7
Figure 69031
Figure 69032
Example: Using Table 690.7, whats the maximum PV source circuit voltage for twenty-three modules each rated Voc 22.60, at an ambient temperature of -7C? Figure 69032 PV Voc Table 690.7 = Module Voc Table 690.7 Correction Factor # Modules per Series String PV Voc = 22.60 Voc 1.14 23 modules PV Voc = 593V
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Mike Holts Illustrated Guide to Understanding 2011 NEC Requirements for Solar Photovoltaic Systems
690.7
Figure 69033
Figure 69034
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690.7
Example: Using the manufacturers temperature coefficient -0.31%/C, whats the maximum PV source circuit voltage for twenty-three modules each rated Voc 22.60, at a cell temperature of 67.8C? Figure 69036 PV Voc = Rated Voc {1 + [(Min. Temp. C - 25C) Module Coefcient %/C]} # Modules per Series String PV Voc = 22.60 Voc {1+ [(67.8C - 25C) -0.31%/C]} 23 modules PV Voc = 22.60 Voc {1 + [42.8C -0.31%/C]}) 23 modules PV Voc = 22.60 Voc {1 + (-13.27%)} 23 modules PV Voc = 22.60 Voc 0.8673 23 modules PV Voc = 451V Figure 69037
CAUTION: Illumination at dawn and dusk is sufficient to produce dangerous voltage, even when the sun isnt shining directly on the PV modules. Although moonlight may not generate lethal voltages, a shock hazard may still exist [690.18 Note]. Figure 69037 (C) Maximum PV System Voltage. For one- and two-family dwellings, the maximum PV system voltage is limited to 600V, which is the standard voltage of electrical building wiring. Figure 69038 (D) Accessible. In one- and two-family dwellings, live parts over 150V to ground must only be accessible to qualied persons. Figure 69039
(E) Bipolar Source and Output Circuits. For 2-wire circuits connected to bipolar systems, the maximum system voltage is the highest voltage between the conductors of the 2-wire circuit if all of the following conditions apply: (1) One conductor of each circuit of a bipolar subarray is solidly grounded. Exception: The operation of ground-fault or arc-fault devices (abnormal operation) shall be permitted to interrupt this connection to ground when the entire bipolar array becomes two distinct arrays isolated from each other and the utilization equipment. (2) Each circuit is connected to a separate subarray.
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Mike Holts Illustrated Guide to Understanding 2011 NEC Requirements for Solar Photovoltaic Systems