July 28, 2016

Electrical Engineering Concepts:  Total Electrical Load with Bottom-Up Approach

Dear Colleagues:

There should never be an error in the Total Electrical Load for any project. And yet, the miscalculation of the Total Electrical Load is one of the most common problems in electrical engineering design.

The proper, and only fail-proof way to do an electrical design, is to add all the electrical loads from the circuit out to the service entrance and do adjustments for changes (bottom-up approach). Ideally, the load downstream should automatically carry over to all upstream panel boards, constantly updating the electrical load. 

In comparison, guestimating the size of the electrical load in conjunction with pre-sets of panel board sizes, equipment disconnects, feeders and overcurrent protection devices at the start of the project leads to an inaccurate baseline on which to build the electrical engineering design.

This is construction, so change is the standard in our business. As we all know equipment is added and deleted, building layouts change, room sizes increase and decrease…the one thing the engineer can count on is that everything affecting the electrical engineering design is in constant flux.

So, how could anyone know the size of the electrical service at the start of a project? No one can guestimate the Total Electrical Load in conjunction with the factors identified above at project start. Only by adding all the electrical loads from the circuit out to the service entrance can the engineer correctly size and adjust for changes in the electrical load for the project.

And what is the outcome of an addition or subtraction mistake? Electrical equipment is either oversized at potentially great cost to the developer or undersized at potentially great risk to safety for those occupying the building.  

So, the Total Electrical Load drives the success of your electrical engineering design.

News about PowerCalc

As you may recall, we started Beta Testing our software last spring for migration to the cloud. With successful completion, our Early Users will now be migrated to our new cloud-connected PowerCalc at launch in August. We expect to be on the market with a new website, new cloud platform and lots of new things in September.

Also, we are launching our video and text blogs in August: PE James: NEC Zone. We’ll be traveling through the NEC from start to finish…it will be a great journey. You’ll receive an announcement on launch.

Thank you for your interest.



James Khalil, P.E.

Inventor of PowerCalc


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