Residences with a single ridge should have two access pathways three feet
wide. The best location for these pathways is from the eave to the ridge. Each roof
slope with modules should have a pathway.
Houses with hips and valleys should have PV modules one-and-one-half feet
to a hip or a valley. The requirement is contingent on the PV module placement
on both sides of a hip or valley.
Smoke Ventilation
Place PV modules three feet below roof ridges for the best smoke ventilation.
Commercial Buildings and Residential Housing—Three or More Units
Access
The roof requires a clear perimeter at least six feet wide around the edges of
the roof.
Exception: Building axes 250 feet or less must have a clear perimeter at least
four feet wide around the edges of the roof.
Pathways
Pathways should take into account the solar installation plan. Pathways adhere to
the following guidelines:
Place pathway over structural elements such as rafters.
Provide pathway on both axes of the roof.
Run pathways as close as possible to the centerlines while following the
roof structure.
Pathways should be routed to steer clear of skylights, roof structures, such as
chimneys, and ventilation hatches.
Install roof access openings with one four-foot-clear pathway to roof edge.
Smoke Ventilation
Here are several ventilation options between array sections:
Pathways eight feet or wider
Areas with roof skylights or ventilation hatches require at least four-
foot pathways
Large roof areas require four-foot or wider pathways bordering 4 x 8 feet
every 20 feet on alternating sides of the pathways
Location and Protection of Direct Current
(DC) Conductors
Wiring and conduit should be located as close as possible to an outside wall. This
reduces tripping. It also maximizes aeration.
CHAPTER 2 Essential Safety Practices for Designing and Installing PV Systems 37
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