Electical Contractor

CODE CITATIONS Article 110 Requirements for Electrical Installations Article 210 Branch Circuits Article 250 Grounding Article 310 Conductors for General Wiring Article 404 Switches Article 408 Switchboards and Panelboards Article 670 Industrial Machinery Branch circuit for refrigerator in dwelling

Please refer to Electrical Contractor magazine for illsutrations. Required Outlets Provisions stipulating the placement of receptacle outlets are covered in 210.52 through 210.63.

• Please refer to ELECTRICAL CONTRACTOR magazine for referenced illustrations. 210.8(A) Dwelling Units Receptacles installed in certain locations must have ground-fault circuit-interrupter (GFCI) protection for personnel.

One of the biggest problems facing the electrical industry is existing power systems’ inability to meet the demands and requirements of the future.

The upstream sags and interruptions caused by faults on the electric utility system are often blamed for being the root of all evil, yet studies have shown that most power quality (PQ) problems originate within the facility itself, as indicated from the following sources:

Having covered the basic laws governing how power quality events propagate through the electrical system, this column’s focus will shift now to “who done it,” or identifying the source of the power quality (PQ) events.

When changes occur and a system doesn’t work properly anymore, it is often good to go back and review the events leading up to the change to determine the why’s of the past, along with the why’s of the present.

As non-linear loads proliferate in the industrial and commercial sectors, problems due to harmonic currents caused by these loads are becoming more common. However, the presence of harmonic currents is often not, in itself, a problem. The real problem may be some secondary effect they cause.

Power quality is very important because of its direct impact on your customer’s business. It used to be that if the power was on, your customer was in business. Today, it isn’t a question of whether the power is on; rather, it is a question of whether the power provided meets the equipment’s needs.