Electrical field answers

An AEGCP is a written OSHA program for temporary power that tests every cord set, temporary receptacle, and cord-and-plug tool for ground continuity and correct termination, on a set schedule, and records the results. Under 29 CFR 1926.404(b)(1) it is one of two ways to protect workers, the other being GFCI protection.

A MEWP is a mobile elevating work platform, the ANSI A92 term for an aerial lift. It raises workers to height on a boom, scissor, or vertical mast. A92 sorts them into Group A, where the platform stays over the chassis, and Group B booms, where it reaches beyond the chassis.

Old solid aluminum branch wiring from roughly 1965 to 1973 is a recognized fire hazard at its connections, where the metal loosens and overheats. The CPSC has documented the higher risk. The wire itself rarely fails; the joints do. Modern, properly terminated aluminum feeders are a different material and are not the hazard.

Arc energy reduction is a means of lowering the incident energy of a potential arc flash by clearing an arcing fault faster than the normal protection settings would. Since the energy scales with how long the arc burns, faster clearing means less energy at the gear and a lower PPE requirement. NEC 240.87 and 240.67 require it on large devices.

The arc flash PPE categories are four levels under the NFPA 70E table method, each with a minimum arc rating: Category 1 is 4 cal/cm2, Category 2 is 8, Category 3 is 25, and Category 4 is 40. Above 40 cal/cm2, energized work is not permitted and the gear must be de-energized.

Incident energy is the thermal energy a worker would receive at a set working distance from an arc, measured in calories per square centimeter (cal/cm2). It is the study's main output and the basis for PPE selection. At 1.2 cal/cm2, a second-degree burn becomes likely on bare skin, which is where the arc-flash boundary is drawn.

Available fault current is the maximum current a bolted short circuit can draw at a specific point in the system. It is set by the utility source, the transformer impedance, the conductor lengths, and the connected motors. Equipment installed at that point must be rated to interrupt or withstand it.

A BESS, a battery energy storage system, stores electrical energy in batteries and releases it on demand to shave peak demand charges, back up loads, store solar, or sell grid services. On commercial jobs it is governed by NEC Article 706 and 705 and, because lithium can catch fire, by the fire code NFPA 855.

Busway is prefabricated electrical distribution made of copper or aluminum bus bars in a grounded metal housing, built in sections that bolt together into a continuous high-current run. Also called bus duct, it replaces parallel cable in conduit on risers, industrial feeders, and overhead data center runs, and it is governed by NEC Article 368 and UL 857.

Pixels per foot, or ppf, is how many horizontal pixels a camera lands on each foot of the scene at the target distance, found by dividing the camera's horizontal pixels by the field-of-view width in feet. It decides whether footage is usable, and it falls off as the scene gets wider or deeper.