This is common in home systems where you have a second power source like solar. Mine has markings like this: https://www.jadelearning.com/blog/pv-system-marking

This is common in home systems where you have a second power source like solar. Mine has markings like this: https://www.jadelearning.com/blog/pv-system-marking-and-labeling/ https://www.jadelearning.com/blog/pv-system-marking-and-labe...