Let's see if I can sumerize this.
IF you have 100K at the line side, and have 100K fuses, then 100K is the first point. Keep in mind, this is based on a theoretical 100K from the service conductors.
The 'start' point is at the utility transformer terminals; the service conductors, length, & type of conduit are factored in, and the 'line' side terminals are the second point. You basically repeat the previous steps to all your points. IF you have motor loads, there are formulas to include the contributions.
The Bussmann 'Plan Review' Book has the complete scenario; I think you can view it online, & it is available to purchase at a small fee. IMHO, it is well worth the price. It will not make you an EE/PE, but it will provide acceptable data.