Derating Sub Panel For Solar

The inverter breaker in the sub panel is the breaker to use in the calculations.

Derating sub panel for solar.

An sma sunny boy 2500hf and an sma sunny boy 5000. The result is that you can shave off a few extra amps before you connect the sub panel output to the main panel board. This was the first time i ever replaced a electrical panel directly next to a window. Pv backfed breaker to be 70a for load side connection to bus.

Pvwatts applies derate factors to determine the amount of ac power that will flow into the grid from the solar array accounting for many of the environmental characteristics of the site as well as system design and chosen components. That sub panel can have a 40a breaker added to it for the 7600w inverter as 100a 40a 140a which is under the 150a. A new solar pv system to be installed. For example picture a 200a main breaker box feeding a 125a sub panel through a 100a breaker with a 100a main breaker in the 125a sub panel.

Design shows main breaker to be derated to 150a in order to stay below 120 of bus rating 150 70 220a 240a. Consider that we are using two string inverters. The pvwatts default overall dc to ac derate factors are based on a system with a string inverter. Main panel has 200a bus and breaker.

John smith is a homeowner in california looking to reduce his electric bill by going solar and he decided to call an installation company that he found on the internet. On this project i was hired as a sub contractor to install the electrical panel for a larger well known solar company. Use the derating factor to account for such factors as soiling of the panels wiring losses shading snow cover aging and so on.