Electical Contractor

CODE CITATIONS Article 225 Feeders Article 230 Services Article 250 Grounding Article 408 Switchboards and Panelboards Article 445 Generators Article 680 Swimming Pools, Fountains and Similar Installation Systems NFPA 20 1999 Standard for the Installation of Stationary Pumps for Fire Protection Grou

* For referenced figures, please refer to ELECTRICAL CONTRACTOR magazine. If the data recorded appears to violate the laws of physics, apply the test of reasonableness to the data before attempting to fix something that isn't real.

A load or circuit with significant loads that have rectified inputs will most likely have a true power factor (W/VA) that is less than displacement power factor (cosine of angle between voltage and current).

A single-phase, rectified input, switching power supply will have a sharp reduction in current at the beginning of a sag, followed by an increase in current to a value greater than the original current levels, until the sag has ended or the equipment trips off line.

CODE CITATIONS Article 90 Introduction Article 110 Requirements for Electrical Installations Article 250 Grounding Article 404 Switches Article 430 Motors, Motor Circuits and Controllers Article 440 Air Conditioning and Refrigerating Equipment Routing grounding electrode conductor Q: We have to inst

Please see Electrical Contractor magazine for referenced Figures.

CODE CITATIONS Article 110 Requirements for Electrical Installations Article 230 Services Article 240 Overcurrent Protection Article 310 Conductors for General Wiring Article 430 Motors, Motor Circuits, and Controllers Article 450 Transformers and Transformer Vaults Article 695 Fire Pumps Warning si

(Please refer to ELECTRICAL CONTRACTOR magazine for referenced figures). On a single-phase circuit, the origin of a voltage sag is usually downstream if the neutral-to-ground voltage significantly increased during the sag.

Article 210 Branch Circuits Article 220 Branch-Circuit, Feeder, and Service Calculations Article 230 Services Article 250 Grounding Article 404 Switches Article 410 Luminaires (Lighting Fixtures) Lampholders, and Lamps Article 445 Generators Article 702 Optional Standby Systems Volume I of the Fire