Course #2: Residential & Commercial Load Calculations, Overcurrent Protection, & Motor Calculations


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Residential & Commercial load calculations NEC Article 220 There are different rules for various types of buildings, and they’re scattered throughout the NEC. Load calculations for commercial occupancies is an important and challenging subject, because there are many different types of commercial buildings and installations — and some have unique rules for calculating service and feeder loads. Commercial occupancies include many different types of businesses and uses, such as banks, stores, restaurants, and office buildings. Some locations, like marinas and mobile home parks, have their own special requirements.

 Overcurrent Protection NEC Article 240. This course provides the general requirements for overcurrent protection and overcurrent protective devices not more than 600 volts,     Article 240, consists of seven parts, provides the requirements for selecting and installing OCPDs.


Motor Calculations NEC Article 430 Calculations for motor circuits are different from those of other circuits because of how motor circuits must handle overcurrent. When motors start across the line, they typically draw five times the running current. This temporary “inrush” is an overload condition. To handle inrush while still providing adequate overcurrent protection, we divide overcurrent protection into two parts: a. Short circuit and ground fault protection. Typically, this is via a fuse or circuit breaker sized large enough to let the motor start. But if it’s large enough to let the motor start, it’s too large to provide overload protection. b. Overload protection. This protects the motor and wiring at a value close to the actual running current of the motor, but with sufficient time delay to allow the motor to start. When you size conductors, short circuit protection, and ground fault protection per Art. 430, the fuse or circuit breaker may seem much larger than it should be for the conductors selected. But the overcurrent protection rules of Art. 240 don’t apply to motors. If a motor installation complies with the requirements of Art. 430, there’s a good chance it won’t “look right.”


6 CEU’s

Tuition: $100.00 if taken individually,  Take 4 Electrical CE Classes for a reduced rate of $375.00

Use coupon code 4classdiscount, when registering for 4 classes

You must sign up for all 4 classes at the same time.

Instructor: Constantinos Papademas PE- Instructor # 14, Constantinos is a licensed professional engineer with 35 years of teaching experience in the areas of Electrical, Electronic and Mechanical systems. He is a licensed electrical contractor, electrical inspector, sub-code official, HVACR contractor and a plumbing contractor. He is also a member of the NJ State Board of examiners of Electrical Contractors.


Additional information


Saturday March 10, 2018; 8:00am to 2:30pm, Wednesday March 28, 2018; 3:30pm to 10:00pm