What are Risks of Not Using a Combiner Box?

Electrical Overload Risks

Not installing a combiner box can lead to electrical overloads, particularly when multiple strings of solar panels are connected directly to an inverter. This is because multiple strings of solar panels can produce different current levels, and without a combiner box, the inverter may not be able to handle the peak current. For example, if you have three 12V, 100Ah strings connected to a 48V inverter, the peak current through the inverter could be 200A, which may exceed the inverter’s maximum rated current. A combiner box would typically limit the current to around 80-100A, reducing the risk of electrical overloads.

Safety Risks

A combiner box also provides a level of electrical isolation between the solar panel strings and the inverter. Without this isolation, an electrical fault on one string could potentially cause a short circuit on a neighboring string, leading to electrical shock or even a fire. A combiner box helps to prevent this by providing a dedicated connection point between each string and the inverter, reducing the risk of electrical shock and fire.

System Efficiency

A combiner box can also help to improve the overall efficiency of the solar system. By allowing each string to operate independently, a combiner box can help to optimize the voltage and current output of each string, reducing energy losses and improving the overall system efficiency. For example, if one string is producing 50V and 100A, while another string is producing 40V and 80A, a combiner box can help to combine these voltages and currents in a way that optimizes the overall system efficiency.