italic = illustrations and diagrams
AC (alternating current)
AC junction box (microinverter systems), 142, 142
anatomy of a solar-electric system, 4
DC-AC string inverter, 143, 143
component connections, 144, 144
electrical diagrams, 84–85
installing, 136
off-grid PV system, 151, 151–52, 164
requirements for underground wiring, 139, 139
sample system designs, 66, 73–74, 75
shutdown and startup procedures, 173–75
standard rapid shutdown system, 55, 55
system diagrams, 7–9
alternating current. See AC
amperage, amps
amp-hours (Ah) in batteries, 158, 160–61, 161, 168–69
effects of series vs. parallel wiring, 58
anatomy of a solar-electric system, 4–10
anchoring
conduits on rooftop, 137–38
footers to rafters, 104, 107–10
module support structures, 40, 42, 44–45
pole mounts, 131
anchors for rooftop safety, 98–99
answering the big three, 16–18
permitting and inspections, 90–92
area
where are the PV modules going?, 16–17
assessing your site. See site assessment
azimuth
how to measure, 25–26
sizing with PVWatts, 30
ballast for flat roofs, 25, 40
frame mounting, 116
installing flat roof systems, 124–25
mounting structures, 44–45
batteries for PV systems
battery-bank wiring, 160–61, 161
capacity, cycle life, 158
charging from a generator, 162–63, 163
comparison chart, 156–57
depth of discharge (DOD), 156, 158, 161, 168, 183
enclosures for batteries, 158, 159, 160
maintenance for off-grid, 178–79, 179
stand-alone inverters, 161–62
supplies for battery maintenance, 179, 179
types, maintenance, cost, 155–56, 158
budget: how much can you spend?, 18
cell. See solar cell
charge controller, 6, 8–9, 10, 183
off-grid basics, 150, 151, 154–55, 163
cleaning and inspecting the array, 176–79
combiner (or junction) box, 183
component connections, 141–43, 141–43
disconnecting, 54–55, 55, 66, 73
installing ground-mount structures, 132–33
installing rooftop modules, 118–120
off-grid PV system, 151
one-line electrical diagrams, 83–85, 84–85
shutdown and startup procedures, 173–75
conduit
embedding in concrete for pole mounts, 131
ground-mount wiring runs, 139, 139–140
one-line electrical diagrams, 83, 84
preliminary installation, 13
rooftop conduit runs, 137–38
rules for both rooftop and ground-mount installation, 140
shown in diagrams, 141, 142, 145, 159
wire types that do and don’t need conduit, 86–87
crew, assembling your, 97–101
critical loads subpanel, 6, 9, 183
critter-proof your array, 41
crystalline silicon, 5, 27, 183–85
PTC ratings, 36
two types of, 38
Database of State Incentives for Renewables & Efficiency (DSIRE), 2, 96
days of autonomy (DOA), 152, 154, 168–69, 183
DC (direct current)
anatomy of a solar-electric system, 4
DC combiner box (string inverter systems), 141, 141
DC electrical circuit rules, 58
DC system size, 26
DC-AC string inverter, 143, 143
DC optimizer. See also microinverters, string inverters, and sample designs
mechanical installation, rooftop, 115–16, 120–21, 125
rapid shutdown protection, 54
troubleshooting, 178
depth of discharge (DOD), 156, 158, 161, 168, 183
designing your PV system, 12, 56–87. See also sample system designs
design process, 63
footer spacing for wind and snow, 72
ground-mount design and materials, 48, 48–49
one-line electrical diagrams, 83–85, 84–85
portrait or landscape?, 49, 49
PV circuit fundamentals, 58–62
system design flow chart, 64
wire types, 86–87
working with solar professionals, 14
direct current. See DC
DIYer’s checklist, 11
electrical installation, 13, 134–47. See also main electrical service panel
component connections, 141–45, 141–45
conduit rules, 140
final inspection and turning on your PV system, 147
final project steps, 136
running conduit, 137–40
signage, 146
credentials with permits, 91
final project steps, 136
shutdown and startup procedures, 173
working with solar professionals, 14
electricity. See also batteries, rapid shutdown, and sample system designs
calculating loads and days of autonomy, 152–155
DC electrical circuit rules, 58
designing your system, 63–64
grounding your modules and racking, 43
loads: how much do you need?, 17
one-line electrical diagrams, 83–85, 84–85, 90
PV safety rules, 172–73
shutdown and startup procedures, 173–75
volts, amps, and watts, 19
emergency power for grid-tied PV systems, 55
enclosures for batteries, 158, 159, 160
financial payback calculation and incentives, 94–97
flat rooftops, 11, 14, 25, 28, 40
frame mounting, 116
installing flat-roof systems, 124–25
mounting structures for, 44–45
tilted racking for, 45
flush-mount rooftop system, 25, 28–29, 183
racking for sloped roofs, 40
sample design, 65–73
tilted racking, 45
footers, 183
footer spacing for wind and snow, 72
installing footers and rails, 110, 110–14
laying out footers and racking, 105
racking for sloped roofs, 40–42
framing dimensions, 105
framing square substitute, 25, 25
generators
off-grid basics, 150, 151, 152
shutdown and startup procedures, 175
types for off-grid systems, 6, 8, 162–63, 163
grid-tied PV systems, 6–7, 7. See also sample system designs
with battery backup, 6, 9, 9–10
emergency power for, 55
rooftop array with string inverter, 66, 66–73
ground-mount structures
support systems, 46–48
grounding your modules and racking, 43
inclinometer, 24
inspections, 91–92
final inspection and utility hookup, 13, 147
overview, 91–92
setting up a ladder safely, 100
inverters. See DC optimizers, string inverters, and microinverters
ladder safety, 100
landscape orientation, 45, 49, 49
assembling the ground-mount structure, 132–33, 132–33
sample design for ground-mount, 76–79, 77
local materials, 94
losses
battery efficiency losses converting DC to AC, 158
shading losses, 32
main electrical service panel, 13
generator connection, 163, 163
grounding your modules, 43
installing and connecting, 136, 144, 145, 147
off-grid systems, 151, 152, 163, 163–64
rapid shutdown protection, 54
safety rules, 172
sample designs, 66, 73–74, 75, 84–85
shutdown and startup, 174
wire types and sizes, 87
maintenance, 176–79
battery maintenance for off-grid systems, 178–79, 179
cleaning and inspecting the array, 176–79
maximum power point tracking (MPPT), 51, 61, 155, 184
measuring
azimuth, 25–26
mechanical installation, ground-mount, 126–33
anchoring pole mounts, 131
assembling the structure, 132–33, 132–33
setting the support posts, 128–31, 129–31
mechanical installation, rooftop, 102–25
flat-roof systems, 124–25
framing dimensions, 105
home runs for string-inverter systems, 120
installing footers and rails, 110–14
installing modules, 115–22
laying out footers and racking, 105
mounting microinverters to modules, 116
removing nails from shingles, 110, 110
rooftop map, 105
wire management, 123
meters, metering. See also PV production meter and utility net meter
meters and main electrical service panel, 144, 145
permits, 90
system design flow chart, 64
microinverters. See also DC optimizers, string inverters, and sample designs
designing your system, 60
electrical component connections, 142, 142, 144, 144
grid-tied system diagram, 7, 7
ground wire needs, 43
mechanical installation, rooftop, 115–21
performance monitoring and optimization, 51–52
rapid shutdown protection, 54–55, 55, 150
shade matters, 32
shutdown and startup procedures, 173–74
vs. string inverters, 53
troubleshooting, 178
modules. See PV modules
monitoring your system, 180–81, 181
monocrystalline cells, 38, 183
mounting
microinverters, 115–16
specs for support systems, 40
structures for flat roofs, 44–45
net metering, 30, 144. See also PV production meter and utility net meter
batteries, 155–61
battery-bank wiring, 160–61
calculating loads, 152–54
stand-alone inverters, 161–62
one-line electrical diagrams, 83–85, 84–85, 90
parallel wiring, 58–59, 59, 184
battery-bank wiring, 160
electrical diagram, 84
permits
amateur installation, 2, 11–12
mounting structure specs, 40
one-line electrical diagrams, 83
permit packet contents, 90–91
working with solar professionals, 1, 14–15
photovoltaics
diagrams of photovoltaic arrays, 84–85
signage for system connect and disconnect, 146
Photovoltaics for Utility Systems Applications (PVUSA), 36
pole-mount structures, 46, 185
anchoring pole mounts, 131
polycrystalline cells, 38
portrait orientation of modules, 49, 49
assembling the ground-mount structure, 132–33, 132–33
sample design for ground-mount, 80–82, 81
PV arrays. See also sample designs
defined, shown in different system diagrams, 6–10, 7–9
electrical wiring diagrams, 84–85
layout for ground-mount array, landscape, 77
layout for ground-mount, portrait, 81
layout for off-grid systems, 154–55
layout for rooftop array with microinverter, 75
layout for rooftop array with string inverter, 66
types of, 28
PV circuit fundamentals, 58–62
PV modules. See also support systems
cell types, 38
color and price, 39
manufacturer, warranty, certification, 36–37
orientation: portrait or landscape?, 49
performance, 36
size, 38
PV production meter, 13
diagrams of grid-tied systems, 7, 9
sample designs, 66, 73, 75, 84–85
sizing your system, 26–30
racking for sloped roofs, 40, 40–42, 42
rapid shutdown systems, 185
connections for rapid-shutdown control box, 136, 141–42, 141–43
diagrams of grid-tied systems, 7–9
electrical diagram, 84
off-grid basics, 150, 151, 164, 164
rules for ground-mount arrays, 133
sample design for rooftop array, 73
shutdown procedures, 173–75
string inverters vs. microinverters, 53
rebates, 1–2, 14–15, 18, 89, 90, 95–96
rebates and tax credit, 96
roofing replacement, 18
rooftop
conduit runs, 137–38
safety, 98–99
safety. See also rapid shutdown system
ladder, 100
PV safety rules, 172–73
rooftop, 98–99
signage requirements, 146
sample system designs, 65
ground-mount, landscape, 76–79, 78
ground-mount, portrait, 80–82, 81
rooftop array with microinverters, 74–75, 75
rooftop array with string inverter, 66–73, 67
series-string wiring. See also string inverter
off-grid batter bank wiring, 160–61
PV circuit fundamentals, 58–60, 59
shade
assessing your site, 17, 22–23
hot-spotting, 177
impact on PV modules, 32–33
performance monitoring, 51
shipping advice, 93
local materials, 94
module selection, 36–39
support structures, ground-mount, 46–48
support structures, rooftop, 40–45
shutdown and startup procedures, 173–75
signage requirements for safety, 146
site assessment, 12, 18, 20–33
how to measure area, 22–23, 23
how to measure azimuth, 25–26
how to measure slope, 24
sizing your system with PVWatts, 26–30
snow, wind, and shade, 31–33
slope, 22
converting roof slope to degrees, 24
how to measure, 24
sloped rooftops
module orientation, 49
racking for, 40
tilted racking for low slope, 45
snow
effect on system, 5, 31–32, 40–41
footer spacing, 72
removal, 176
solar cell
cell efficiency, 37
definition and diagram, 4–5, 5
impact of shade, 32
monocrystalline or polycrystalline, 38
troubleshooting, 177
solar panels. See PV modules
solar professionals, 1–2, 4, 10–11
when to consult, 42, 48, 93–94, 103, 149, 161
working with, 14–16
string inverters. See also microinverters, DC optimizers, and sample designs
adjusting to hit the MPP, 62
electrical component connections, 136, 141–44, 141–44
grid-tied system diagram, 7
home runs for string-inverter systems, 120
mechanical installation, ground-mount, 133, 133
mechanical installation, rooftop, 115, 119–22, 125
vs. microinverters, 53
off-grid system, 150–51, 151, 154, 160–61
performance monitoring and optimization, 51–52
rapid shutdown protection, 54–55, 55, 133
selecting the right one for your system, 63–64
series and parallel wiring, 58–60, 59
shade matters, 32
shutdown and startup procedures, 173–75
troubleshooting, 178
support systems
critter-proof your array, 41
ground-mount structures, 46–48, 48
grounding modules and racking, 43
mounting specs, 40
mounting structures for flat roofs, 44–45
racking for sloped roofs, 40–41
roofs without asphalt shingles, 42, 42
tax breaks and credits, 2, 14, 18, 96
ten-step overview of going solar, 12–13, 12–13
tracking for ground-mount systems
pole mounts, 46
troubleshooting, 177–79
underground wiring requirements, 139, 139
utility net meter, 185
diagrams of grid-tied systems, 7, 9
how net metering works, 30
installing and connecting, 136, 144–45, 145, 147
voltage, 185
battery voltage capacities, 156, 158, 160-61
charge controllers, 154–55
DC electrical circuit rules, 58
effects of series vs. parallel wiring, 58, 59
PV system design flow chart, 64
PV system losses, 29
volts, amps, and watts, 19
WEEBs (Washer Electrical Equipment Bond), 43
deflector panels, 125
footer spacing, 72
preventing wind uplift on the modules, 23, 25
wire types for PV systems, 86–87