To download the Wheelock Notification Appliance Calculator, click on the link below and save the file to your desktop. Instructions on how to operate the tool can be found in the Help tab. The Wheelock Notification Appliance Calculator allows users to input different variables such as distance of circuit, wire gauge, power supply and device type in order to calculate NAC currents and end-of-line voltage. It also enables users to calculate minimum battery amp hours required for the power supply.