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PowerPoint® Presentation

Chapter 11
Electrical Integration
National Electrical Code • Voltage
and Current Requirements •
Conductors and Wiring Methods •
Overcurrent Protection • Disconnects •
Grounding • Battery Systems


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Chapter 11 — Electrical Integration

Many articles in the
NEC® are applicable to
the electrical integration
of a PV system,
particularly Article 690.


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Chapter 11 — Electrical Integration

The NEC® defines the
various circuits and
components in PV
systems and specifies
their requirements.


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Chapter 11 — Electrical Integration

Array open-circuit voltage
is corrected for low
temperatures to yield the
maximum possible PV
circuit voltage.


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Chapter 11 — Electrical Integration

Conductor sizes
typically used in PV
systems range from
18 AWG to 4/0 AWG.
Conductors may be
solid or stranded.
Larger conductors
have lower resistance
for a given length.


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Chapter 11 — Electrical Integration

Ampacity is the currentcarrying capacity of a
conductor, which
depends on the
conductor’s type, size,
and application.


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Chapter 11 — Electrical Integration

Conductor
ampacity must be
derated for high
operating
temperatures.


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Chapter 11 — Electrical Integration

For conduits installed on rooftops, an extra temperature
adder is needed to account for the extreme ambient
temperatures of the environment. The adjusted ambient
temperature is then used to determine the temperaturebased ampacity correction factor.


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Chapter 11 — Electrical Integration

Conductor ampacity must be derated for more than
three current-carrying conductors together in a
conduit or cable.


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Chapter 11 — Electrical Integration

Information printed on
the outer jacket of a
conductor includes
size, insulation type,
environmental
exposure, temperature
ratings, and listing
approval.


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Chapter 11 — Electrical Integration

Conductors in different parts of a PV system have
different application requirements.


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Chapter 11 — Electrical Integration

Source-circuit conductors
for PV module
interconnections within
the PV array are
permitted to be exposed
if the conductor insulation
has the required
environmental
resistances.


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Chapter 11 — Electrical Integration

Modules are typically
connected together in PV
source circuits with
external, exposed
connectors.


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Chapter 11 — Electrical Integration

When tightened and
torqued properly, screw
terminals produce secure
and low-resistance
connections.


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Chapter 11 — Electrical Integration

Lugs are crimped conductor terminations in ring, fork,
spade, or pin shapes.


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Chapter 11 — Electrical Integration

Splicing devices, such as
screw terminal blocks,
are used in PV systems
to connect or extend
conductors or to parallel
array source circuits.
This type of terminal
would not be used for a
tap.


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Chapter 11 — Electrical Integration

Several NEMA plug-andreceptacle configurations
are acceptable for use
with DC branch circuits.


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Chapter 11 — Electrical Integration

Module junction boxes
contain and protect the
module terminal
connections and diodes
in the source circuit.
Some are fieldaccessible.


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Chapter 11 — Electrical Integration

Multiple PV source
circuits are combined into
the PV output circuit
within the combiner box.


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Chapter 11 — Electrical Integration

Blocking diodes may be
used in the source circuit
whereas bypass diodes
are installed within a
module or its junction
box. These diodes help
preserve system output
and protect PV modules
from damage.


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Chapter 11 — Electrical Integration

Bypass diodes may be
installed in the module
junction box.


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Chapter 11 — Electrical Integration

A number of different
types of conduit may be
used in PV systems if
they have the appropriate
ratings.


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Chapter 11 — Electrical Integration

Current-limiting
overcurrent protection
devices open a short
circuit before current
reaches its highest value.


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Chapter 11 — Electrical Integration

Overcurrent protection
devices include fuses
and circuit breakers of
various types and
ratings.


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Chapter 11 — Electrical Integration

Array source circuits are
fused individually within
the source-circuit
combiner box.


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Chapter 11 — Electrical Integration

Overcurrent protection
for the inverter output
circuit depends on the
system type. Overcurrent
protection and
disconnecting means can
be accomplished by
using circuit breakers or
fused disconnects.


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Chapter 11 — Electrical Integration

Connecting a 120 V
inverter to a 120/240 V
panelboard with multiwire
branch circuits may
cause dangerous
overloading in the
grounded (neutral)
branch circuit conductor
and must be avoided.


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Chapter 11 — Electrical Integration

The array disconnect
opens all current-carrying
conductors in the PV
output circuit.


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Chapter 11 — Electrical Integration

The AC disconnect of an
interactive PV system
may be located close to
the main utility service
disconnect, which can
satisfy utility
requirements for an
external, visible-break,
and lockable PV system
disconnect.


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Chapter 11 — Electrical Integration

Switches or circuit
breakers are required to
isolate and disconnect all
major components in a
PV system from all
ungrounded conductors
of all power sources.


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Chapter 11 — Electrical Integration

The DC grounding
system and the AC
grounding system must
be connected together
with a bonding
conductor. The array
may also require a
separate grounding
electrode system.


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Chapter 11 — Electrical Integration

Some inverters include fuses as array ground-fault
protection in their DC input circuits.


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Chapter 11 — Electrical Integration

Circuit breakers can be
used for array groundfault protection when the
inverter does not already
provide this protection.


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Chapter 11 — Electrical Integration

A ground-fault circuit
interrupter (GFCI) senses
differences between the
current in the grounded
and ungrounded
conductors, indicating a
ground fault, and opens
the circuit in response.


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Chapter 11 — Electrical Integration

Modules should be
connected to each other
and the mounting
structure with grounding
conductors to ensure a
continuous grounding
connection.


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Chapter 11 — Electrical Integration

Equipment grounding
conductors are sized
based on the rating of the
overcurrent protection
device in the circuit.


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Chapter 11 — Electrical Integration

Lightning protection is
especially important in
the southeastern states,
which have the highest
lightning-strike density in
the United States.


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Chapter 11 — Electrical Integration

A lightning protection
system includes a
network of air terminals,
a grounding electrode
(down) conductor, and a
set of grounding
electrodes.


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Chapter 11 — Electrical Integration

Surge arrestors may be
incorporated into
equipment or can be
installed on circuits as
separate devices.


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Chapter 11 — Electrical Integration

Connectors may be used
for disconnecting highvoltage battery banks
into lower voltage
segments for servicing.