National Electrical Code® for discussion only - photovoltaic systems | Ground mounted arrays ...

[Information Technology and Solar Solutions]

Besides NEC® 690, there are other areas of the National Electrical
Code® which would be applicable to the photovoltaic systems. With
regards to ground mounted arrays, for instance, would be

NEC® 110.26(A)(1) and Table 110.26(A)(1) Working Spaces and if
"Exposed live parts on both sides of the working space." would be 1.22
m (4 ft).

NEC® 110.27 (A)(4) also would be applicable -"...elevation of 2.5 m (8
ft) or more" if not readily accessible -"guarded against accidental
contact."

NEC® 200.6 Means of Identifying Grounded Conductors

NEC® 300.5 Underground Installations

NEC® Table 310.16 | Table 310.17 ...

NEC® Table 310.15(B)(2)(a) Adjustment Factors for More Than Three
Current-Carrying Conductors in a Raceway or Cable

NEC® 338.10(4)(b) Uses Permitted. Exterior Installations "supported in
accordance with NEC® 334.30 for Securing and Supporting." "support
shall be supported and secured by staples, cable ties, straps,
hangers, or similar fittings designed and installed so as not to
damage the cable, at intervals not exceeding 1.4 m (41/2 ft) and
within 300 mm (12 in.) of every outlet box."

For example, NEC® 690

NEC® 690.5 "Exception No. 1: Ground-mounted or pole-mounted
photovoltaic arrays with not more than two paralleled source circuits
and with all dc source and dc output circuits isolated from buildings
shall be permitted without groundfault protection" Although the
inverter would typically have GFP.

NEC® 690.31 Methods."photovoltaic source and output circuits operating
at maximum system voltages greater than 30 volts are installed in
readily accessible locations, circuit conductors shall be installed in
a raceway

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.
.

Along with Table 310.15(B)(2)(c) Ambient Temperature Adjustment for
Conduits Exposed to Sunlight On or Above Rooftops and not typical for
ground mounted arrays. With regards to temperature, there
calculations performed on the module temperature coefficient of power
to predict the sunlight with for instance a Daystar meter and an IR
thermometer. Although voltage drop would be calculated on the both
the AC or DC side, it's the calculation of power loss and the derate
factor we discussed in class. Which think is important for instance,
Chapter 9 Table 8 for DC and Chapter 9 Table 9 for AC ... And NEC®
90.4 :)

One important thing to know about photovoltaic systems (PV) they
considered in "wet" locations in accordance to NEC® 100 Location,
"Wet. Installations underground or in concrete slabs or masonry in
direct contact with the earth; in locations subject to saturation with
water or other liquids, such as vehicle washing areas; and in
unprotected locations exposed to weather."

Also with regards to a ground fault, the ability to isolate the
specific module number which is defective as # TVoc = [+ / -] =
Voc*12 # Module # = [G|-]/TVoc/12, where [G|-] is the measurement
voltage from the ground to negative. And the module # as counted from
the negative lead of the string. If 12 modules.

For your information with regards to there are many online courses,
but some for discussion would be:

The National Electrical Code (NEC): A Practical Application

http://www.uluniversity.us/catalog/display.resource.aspx?resourceid=99571

BlueVolt Continuing Education

http://go.bluevolt.com/CoBrandTemplate/CourseCatalog.aspx?Brand=default&CategoryID=884