Combiner Boxes for Solar Photovoltaic Installations - Eaton Canada

Combiner Boxes Defined
Combiner boxes are used in solar installations to combine
the inputs from multiple strings of solar panels into one
output circuit. If viewed on a one-line diagram, combiner
boxes would look like a “reverse-fed panelboard.” Meaning
that instead of one feeder being broken into multiple branch
circuits, the combiner takes multiple branch feeds from
solar strings and groups them into one output.
An "array" may be one PV panel or many in series, and may
range from a single 12 volt panel up to multi panel high
voltage arrays for grid tie systems. Solar PV Grid tied
systems are typically 600 volts DC.
String Combiners, often referred to as source combiners,
are located closest to the “strings” of solar panels. Since
each string of PV panels are connected in series, the
maximum current potential tends to be less than 15A per
string. At Eaton we utilize individual fuse holders capable
of accepting up to a 30A fuse. There are normally between 4
and 12 strings connected to each combiner box. They may
be grouped together using copper bus which is tied to a set
of outgoing terminals.
Combination String Combiner
In most solar installations it is advisable that a load break
DC switch be included in order to isolate the individual
string fuses for safe removal. At Eaton, we have combined
our DC Disconnect along with our individual string inputs
into a CSA Approved Combination String Combiner.
Array combiners provide the next level of connection. An
array combiner is made up of larger incoming connection
points (100A-200A fuse blocks or DC breakers) and allows
for the grouping of multiple string combiner outputs into a
single set of outgoing terminals. You will normally only
find array combiners on a large projects above 100kW and
they are often provided as part of the inverter assembly
although it is not uncommon to see multiple array
combiners used on a large scale project.
Smart Combiners
With income generation tied to Solar PV production it is not
uncommon for owners to demand that performance
monitoring be included. At Eaton we offer a scalable string
monitoring solution that will allow for monitoring up to 15
strings in a single combiner box. Eaton’s string monitoring
package is capable of providing antitheft control and solar
PV analysis (DC V,A and W metering). Modbus
communication is standard and may include a smart energy
management box with built in web sever.
Combination and Non-combination
String Combiners
Solar Photovoltaic installations
Features
• Suitable for NEC article 690 applications to UL 1741
• CSA certified to C22.2 No. 107.1 and assembled in Ontario
• Range 60, 100, 200Ampere 600VDC, single pole safety
switch available as fusible or non fusible main disconnect,
with 4 to 24 string circuit, 30Ampere, 600VDC, finger-safe
fuse holders
• Continuous duty rated
• Main Disconnect load break rated.
• Main fuse is isolated when switch is in OFF position.
• Class R fuse clips standard for the main disconnect and
midget class finger-safe fuse holders for the string circuits.
Fuses not included.
• Main disconnect is single pole and suitable for switching one
circuit
• Multi-position isolated negative ground
• Short circuit withstand rating 10kA @600VDC
• Standard offering type 12/3R enclosure electrostatic coated
painted steel ASA 61 grey (Optional 4X stainless)
• Highly visible, electrical shock warning label for line and
load terminals mounted on front door of switch.
• Highly visible ON / OFF marking on enclosure.
• Operation temperature: -30ºC to +50ºC
• Multi-position equipment ground and separate single
conductor lay in lug for continuous ground #4 –14 awg.
PA08323011K www.eatoncanada.ca/solar 2