GER Licensed Electrical Inspector key terms

The fixed relationship among voltage, current, and resistance in a circuit, expressed as voltage equals current multiplied by resistance. Inspectors use it to verify that measured current and voltage are consistent with expected conductor loading.

The total opposition a circuit presents to alternating current, combining resistance with inductive and capacitive reactance. It governs actual current flow in AC systems and matters when sizing conductors and evaluating equipment performance.

The ratio of real power to apparent power in an AC circuit, reflecting how much supplied current performs useful work. Low power factor increases current for the same load, affecting conductor and equipment sizing calculations.

The reduction in voltage along conductors caused by their resistance and reactance under load. Branch-circuit and feeder runs are checked so delivered voltage stays adequate for connected equipment to operate properly.

The maximum current a conductor can carry continuously under specified conditions without exceeding its temperature rating. It depends on conductor material, size, insulation type, ambient temperature, and number of current-carrying conductors.

The required adjustment of a conductor's tabulated ampacity for conditions such as elevated ambient temperature or multiple current-carrying conductors bundled together. Derating prevents insulation damage from accumulated heat.

The proportion of a raceway's cross-sectional area occupied by conductors and cables. Limits exist so conductors can be installed without damage and heat can dissipate adequately.

A load expected to operate at maximum current for three hours or more. Branch circuits and feeders serving continuous loads are sized with additional capacity beyond the calculated load.

A structured method of summing connected loads, applying demand factors, and determining the minimum service, feeder, and branch-circuit capacity required for a building. Results drive conductor and equipment selection.

A ratio applied to connected load to account for the fact that not all loads operate simultaneously at full capacity. It permits smaller service and feeder sizing than the total connected load would require.

The conductors that carry power from the utility supply point to the service equipment disconnecting means. Their size is based on the calculated load and must coordinate with the service overcurrent protection.

The set of conductive elements, such as rods, pipes, or concrete-encased electrodes, that establishes a deliberate connection between the electrical system and the earth. It provides a reference potential and a path for certain fault and surge currents.

The conductor that connects normally non-current-carrying metal parts of equipment to the system grounding point. It provides a low-impedance fault path so overcurrent protection operates promptly.

A conductor that ensures electrical continuity between metal parts required to be electrically connected. Bonding equalizes potential and prevents dangerous voltage differences between adjacent metallic systems.

A fuse or circuit breaker designed to open a circuit automatically when current exceeds a safe level. Selection considers conductor ampacity, equipment ratings, and the type of fault current available.

The maximum fault current a protective device is rated to safely interrupt without damage or hazard. The device's rating must equal or exceed the available fault current at its installation point.

The maximum short-circuit current the supply system can deliver at a given point in the installation. It is compared against equipment ratings to confirm the equipment can withstand a fault.

A device that detects small current imbalances between the ungrounded and grounded conductors and opens the circuit quickly. It protects people from shock in wet or otherwise hazardous locations.

A protective device that senses characteristic arcing signatures in branch-circuit wiring and de-energizes the circuit. It addresses fire risk from damaged or deteriorated conductors.

The calculated volume of a box required to accommodate conductors, devices, fittings, and grounding conductors. Adequate volume prevents insulation damage and overheating at splices.

The clear area in front of electrical equipment that must remain unobstructed so qualified persons can safely service the equipment. Depth and width depend on voltage and equipment conditions.

A sudden release of energy caused by an electrical arc between conductors or to ground, producing intense heat, light, and pressure. Inspection includes verifying labeling and safe working distances.

Markings applied to electrical equipment identifying ratings, circuit sources, and required safety information. Labels support safe operation, maintenance, and inspection verification.

Accepted by the authority having jurisdiction as meeting applicable codes and standards, often demonstrated by listing or field evaluation. Inspectors rely on this status when accepting equipment and materials.

The formal recognition by a qualified testing organization that a product meets designated safety standards. Listed equipment carries a mark indicating third-party evaluation.

The organization or individual responsible for enforcing code requirements and approving equipment, materials, and installations. The inspector works under or as this authority and documents decisions accordingly.

The pre-construction examination of drawings and specifications for compliance with code requirements. It identifies deficiencies before installation, reducing field corrections and rework.

A written record identifying code deficiencies found during inspection and specifying required corrective action. It documents the finding, the code basis, and the re-inspection outcome.

The documented account of an inspection, including date, scope, observed conditions, code references, and disposition. Clear records support enforcement and demonstrate professional diligence.

The system of designating areas by the likelihood and duration of flammable gases, vapors, dusts, or fibers. Classification determines permitted wiring methods and equipment construction.

Enclosures designed to contain an internal ignition and prevent ignition of the surrounding flammable atmosphere. They rely on flame paths and temperature limits, not on excluding gases entirely.

A circuit in which energy is limited so that sparks or thermal effects cannot ignite a flammable atmosphere under normal or specified fault conditions. It typically requires associated apparatus and control drawings.

An area where flammable gases or vapors are or may be present in quantities sufficient to produce ignitable mixtures. Divisions or zones further describe the likelihood of presence.

Failure to exercise the degree of care a reasonable professional would exercise under similar circumstances. For inspectors, it can arise from missed code violations or inadequate documentation.

The level of diligence and competence expected of a similarly situated professional inspector. It frames judgments about whether an inspection met accepted practice.

A situation in which an inspector's personal, financial, or other interest could improperly influence professional judgment. Disclosure and recusal protect objectivity and public trust.

The process of applying adopted electrical code requirements consistently through review, inspection, and corrective action. It requires impartiality, accurate citations, and fair treatment of all parties.