Managing Change in Your Electrical System


Maintain accuracy of your electrical documentation.

As you make changes in your electrical system, there are obviously many different things to keep in mind and consider. One of the most important things to remember is maintaining the accuracy of your documentation. Often the most difficult challenges for maintenance staff and contractors alike comes when the documentation for an electrical system does not accurately represent the infrastructure physically in place. Here is a short list of electrical documents you should be maintaining for your facility.

Electrical One-Line

The top item would be an overall electrical one-line. A one-line shows how the system is connected and what pieces of equipment are part of the system.  In addition, the one-line would show the sizing of the equipment and the sizing of the wiring as it connects these pieces of equipment.  This allows you to know the capacity of the equipment.

Electrical Load List

Next would be an electrical load list. This list would include all the electrical loads and more specifically the motors that are on the system.  Some items that this list should include:

  1. Motor Tag number
  2. Description
  3. Horsepower or Power rating of the load
  4. Voltage
  5. Type of starter (if a motor) – FVNR, Soft Start, VFD, Reversing, etc.
  6. Location of the motor starter (Which MCC or panel the starter is fed from)

Having these loads up to date on a list will allow you to manage both the loading of the system as well as being able to use this list for lockout/tagout procedures by knowing the location of the loads.

Other Drawings

Other drawings to consider as part of your electrical documentation would be:

  1. Area classification plan
  2. MCC front or one-lines for locating starters and understanding future capacity
  3. Panelboard schedules
  4. Underground routing documentation
  5. Grounding drawings
  6. Electric room layouts

By: Brent Kooiman