Selling and Administrative Expenses, also called Selling, General and Administrative Expenses, are the net operating expenses of the business that are not part of the cost of goods sold. Examples of selling and administrative expenses include advertising and the salaries of people not directly related to manufacturing a product, as well as recurring expenses as insurance and rent.
For those of you wondering, what is a protection relay? Littelfuse has the answer. A protection relay is a smart device that receives inputs, compares them to set points, and provides outputs. Inputs can be current, voltage, resistance, or temperature.
Interposing Relay is the auxiliary relay which is used to isolate the two different systems/ devices. This could be because they have different 0V references, different voltages, AC vs. DC. For example, let's say the relay of a PLC can only avail 1 A at 110 VAC, but the Controller which is to be connected to the relay requires 1.5 A at 110 VAC.