How do I calculate my inverter’s OCPD (breaker)?

Generally, you can take the inverter maximum AC power in Watts and divide it by the operating voltage (240V for most residential applications). This means that a 7600W inverter would require an OCPD (breaker) of only 32A but because grid-tie inverters can operate longer than 3 hours, solar PV is considered a continuous load and therefore requires that we apply a 125% safety factor to the size of the breaker. This means a 7600W inverter actually requires a 40A breaker to interconnect it to the main electrical panel. Examples: 7600W/240V = 31.66A X 125% = 39.58A = 40A ( the next closest standard breaker size is 40A) 10000W/240V = 41.66A X 125% = 52.08A = 60A (the next closest standard breaker size is 60A) Although oftentimes inverters have a name or model number that references their AC power rating.  For example, an SMA SB 7.7 (7.7 for 7.7kW or 7700W), it is possible for the inverter naming to not exactly match its maximum output, and so to be 100% safe, we recommend that you check the inverter datasheet and find the ‘maximum continuous output current’ in Amps, multiply it by 1.25 and use the next biggest standard size breaker. Standard breakers size are (in Amps) but it can vary depending on the brand: 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100 etc