Page 96 - Solar Power in Building Design The Engineer's Complete Design Resource

66 SOLAR POWER SYSTEM DESIGN CONSIDERATIONS

Bussman

Midget fast-acting fuse, ampacity rating 0.1 to 30 A– Special fuse designation for
this class of fuse is ATM.

JUNCTION BOXES AND EQUIPMENT ENCLOSURES
All junction boxes utilized for interconnecting raceways and conduits must be of
waterproof construction and be designed for outdoor installation. All equipment
boxes, such as dc collectors must either be classified as MENA 3R or NEMA 4X.

Solar Power System Wiring

This section covers solar power wiring design and is intended to familiarize engineers
and system integrators with some of the most important aspects related to personnel
safety and hazards associated with solar power projects.
Residential and commercial solar power systems, up until a decade ago, because of
a lack of technology maturity and higher production costs, were excessively expensive
and did not have sufficient power output efficiency to justify a meaningful return on
investment. Significant advances in solar cell research and manufacturing technology
have recently rendered solar power installation a viable means of electric power cog-
eneration in residential and commercial projects.
As a result of solar power rebate programs available throughout the United States,
Europe, and most industrialized countries, solar power industries have flourished and
expanded their production capacities in the past 10 years and are currently offering
reasonably cost effective products with augmented efficiencies.
In view of constant and inevitable fossil fuel-based energy cost escalation and avail-
ability of worldwide sustainable energy rebate programs, solar power because of its
inherent reliability and longevity, has become an important contender as one of the
most viable power cogeneration investments afforded in commercial and industrial
installations.
In view of the newness of the technology and constant emergence of new prod-
ucts, installation and application guidelines controlled by national building and
safety organizations such as the National Fire Protection Association, which estab-
lishes the guidelines for the National Electrical Code (NEC), have not been able to
follow up with a number of significant matters related to hazards and safety pre-
vention issues.
In general, small-size solar power system wiring projects, such as residential instal-
lations commonly undertaken by licensed electricians and contractors who are
trained in life safety installation procedures, do not represent a major concern.
However, large installations where solar power produced by photovoltaic arrays
generates several hundred volts of dc power require exceptional design and installa-
tion measures.