Before drawing the blueprints, talk to your local building department. They have a guideline for panel mounting heights. For example, the city of Olympia, Washington, specifies a panel height of no more than 78 inches, or 6 1/2 feet, for commercial installations. Some other townships may specify other maximum panel heights. The city of Milpitas, California specifies that the topmost breakers be no more than 6 feet 7 inches from the ground. Also, local codes may specify the clear area in front of the panel. For the city of Olympia, the clear area must be 30 inches wide, with a clear depth of 36 inches.
Codes follow a normal human height premise. Most normal adult human beings are anywhere from 4 feet tall to about 6 feet tall. The breakers have to be be reached without stooping down low or reaching high above your head. The breakers should be reached comfortably by just extending your arm.
An often-overlooked area by electrical builders is the height of the outdoor main meter panel. Outdoor meter panels have their own unique height requirements, again specified by local codes. For example, the city of Tempe, Arizona, Building Safety Division specifies the middle of the face of the meter must fall between 4 feet and 6 feet 3 inches from the ground. The ideal recommended height by the Tempe Building Safety Division is 5 feet from the ground. Another township, the city of San Jose, California, specifies a height between 48 inches to 66 inches off the ground.Since every township is different, check with your local building department before installing the main meter panel.
After the electrical construction part of the job is finished, the building inspector is usually called to do the final inspection. During the inspection, she takes out a tape measure and measures the height of the topmost breaker to the floor. If the panel height falls within the specified parameters, the inspector "signs off," or approves that part of the job.