The Calculate All Circuit Loads command is used to recalculate all of the loads on all of the circuits on all of the distribution equipment in the project. It guarantees that all of the loads shown in distribution equipment schedules are correct.
To recalculate all circuit loads, go to
Ribbon: DM Electrical->Utilities-> 
->Calculate All Circuit Loads
Pulldown Menu: DM Electrical->Utilities->Calculate All Circuit Loads
All of the loads on all of the circuits in the project will be reset to 0. The load on each equipment will then be added to the circuit it is connected to. Once all of the branch circuits are updated, the loads will be transferred between distribution equipment, starting from the bottom equipment and working up toward the utility.
Generally, this command does not need to be run. Circuit loads are updated automatically as you modify your design. Recalculating all of the loads can take a long time, especially on large projects.
You can use the Recalculate Selected Circuit and Recalculate All Circuits buttons on the Circuiting dialog box to recalculate smaller portions of the project. See the Circuiting section for more information.