Trying to understand aic. I do mostly hvac, chillers and pumps. I am normally in a existing building where i need to find a extra space in the existing main panelboard.As a example I just installed a 800a 3p 480v mlo panel in a mech. room with 2 400a breakers each feeding a new chiller. This panel is fed from a 800a fused disconnect in the main panel. Do fuses get aic ratings? Can i just copy the rating of other branch panels in the building? Is the rating of all panels in a building the same, if not does the rating go up or down the farther you get from the main panel? john