Quick Answer
An oversized breaker for a solar application can lead to unnecessary heat generation, reduced lifespan, and increased risk of electrical fires, as well as higher upfront costs for the larger breaker.
Over-Sizing Risks and Consequences
When a breaker is oversized for a solar application, it can result in excessive heat generation due to the excess current flowing through the breaker. This heat can cause the breaker to degrade faster, reducing its lifespan and potentially leading to electrical fires. The cost of a larger breaker can be significantly higher than a properly sized one, making it a costly mistake.
Determining Proper Breaker Sizing
To determine the correct breaker size, you need to calculate the maximum current that will be flowing through it. This involves calculating the total solar panel array output, accounting for inverter efficiency, and ensuring the breaker can handle any potential surges or spikes. A general rule of thumb is to size the breaker to handle at least 125% of the inverter’s maximum output current to account for any unexpected spikes.
Best Practices for Breaker Sizing
Some best practices for sizing breakers for solar applications include using a 20A to 30A breaker for small solar arrays (less than 5 kW) and a 40A to 60A breaker for larger arrays (5 kW to 10 kW). It’s also essential to consult the inverter manufacturer’s guidelines for recommended breaker sizes and follow local electrical codes and regulations. Additionally, it’s a good idea to use a breaker with a high interrupting capacity (HI) rating to ensure it can handle any potential surges or spikes.
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