Solar Power Solutions

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 sting 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.

Features

• Suitable for NEC article 690 applications to UL 1741
• CSA certified 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.