A PV combiner box is an electrical distribution box where DC breakers are housed. Its main purpose is to combine multiple DC inputs from the panels in the system into a single DC output. This output is then connected to a charge controller or inverter, depending on the type of system. They also allow you to transition to larger wires between the array and the batteries or inverter to minimize transmission voltage drop.
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Why are combiner boxes so important?
Within a combiner box, we’ll find a section to place and connect circuit breakers. By installing circuit breakers into combiner box allows a layer of safety. Circuit breakers is “an automatically operated electrical switch designed to protect an electrical circuit from damage caused by excess current from an overload or short circuit. Its basic function is to interrupt current flow after a fault is detected” according to Wikipedia.
What else can you find in a combiner box?
Apart from circuit breakers, combiner boxes also provide grounding or surge protection devices which adds an additional layer of safety. In the event of a shorting or overload caused by any excess current, the circuit breaker would halt the excess current from reaching the solar inverter or charge controllers.
Don’t worry if you do not find that your solar PV system may not have a combiner box as its usually utilized for larger solar PV projects and certain residential solar projects may not need to include a combiner box. Whereby it is sufficient to connect a small residential solar PV project directly to a solar inverter instead.
Can I put AC and DC Breakers in the Same Box?
Yes and no. A solar combiner box is meant to combine many inputs to make it into one output to reduce wiring. If you use DC and AC breakers in the same box, you would not be combining the inputs, since DC and AC cannot be combined in this way, so essentially the box would be a junction box strictly for breaker housing and not combining. Also, if you put both DC and AC combiners in a PV combiner box, it would not pass code.
Where should a solar combiner box be mounted?
Ideally, you want your solar combiner box to be mounted on a north-facing wall where shade is available. This helps to limit the amount of direct sunlight it endures. As you can imagine, long periods of sun exposure can increase the temperatures of the internal combiner. This can reduce both the effectiveness and lifespan of the components in the box. It should also be noted that size does matter. Larger enclosures allow greater air volume and surface area. This is handy in cooling the internal components. As well, by allowing more room to work during installation and maintenance, larger enclosures make field wiring much easier. For more information about solar combiner boxes,You can email us at sales2@witproton.com.
