Browse 34 essential 24 hour electrician terms and definitions used by professionals in Pittsburgh.
Term Index
Open any term below for a dedicated definition page.
AFCI is a protective device that detects dangerous electrical arcing and disconnects power before an arc starts a fire. AFCI protection may be built into a circuit breaker or installed at a receptacle. The device monitors electrical waveforms and responds to arc patterns that ordinary overcurrent protection may not detect.
Ampere is the SI unit of electric current. It measures how much electric charge passes a point in a circuit each second. Electricians write the unit as An or amp. A circuit rated at 15 amperes can safely carry a specified current when its wiring, devices, and overcurrent protection match the design.
Breaker Panel is the enclosure that receives electricity from a utility service and distributes it through individual branch circuits. The panel contains circuit breakers that open when current exceeds a circuit’s safe rating. A breaker panel also provides connection points for neutral and grounding conductors, helping protect wiring, equipment, and people from electrical faults.
Circuit Breaker is an automatic electrical switching device that stops current when a circuit draws too much electricity or develops a fault. The breaker protects conductors, equipment, and people from damage caused by overloads and short circuits. Specialized breakers also detect arc faults or ground faults and interrupt power within the circuit.
Conduit is a tube or raceway that encloses and protects electrical conductors from physical damage, moisture, heat, and other hazards. Electrical conduit may be made from steel, aluminum, PVC, or other approved materials. Installers select its type, size, fittings, and support method according to wiring conditions and electrical code requirements.
Copper Wiring is an electrical conductor system that uses copper wire to carry power or signals between a source, control device, and load. Copper has low electrical resistance, bends easily, and forms reliable connections. The wiring includes solid or stranded conductors, insulation, terminations, and protective devices selected for voltage, current, installation method, and circuit conditions.
Electrical Grounding is the intentional connection of an electrical system or equipment to earth through a conductive path. This path carries fault current away from people and equipment, helps stabilize voltage, and supports protective device operation. Grounding works with bonding, grounded conductors, and circuit breakers to reduce shock, fire, and equipment damage risks.
Electrical Panel is the enclosure that receives electricity from a service utility and distributes it through branch circuits. The panel contains circuit breakers or fuses, bus bars, neutral connections, and grounding connections. Each protective device limits current to help prevent wire damage, overheating, fire, and electric shock during electrical faults.
Electrical Permit is official approval from a local building department to install, alter, repair, or extend electrical systems. The permit connects proposed work to adopted electrical codes, required plans, inspections, and final approval. Permit rules vary by jurisdiction and project type, so the property owner or electrical contractor must verify local requirements before work begins.
Electrical Tape is an insulating adhesive tape designed to cover, protect, bundle, or identify electrical wires and cable components. Most types use vinyl backing because vinyl resists moisture, abrasion, and moderate heat. Electrical tape supports electrical work, but it doesn't replace proper wire connectors, cable insulation, junction boxes, or circuit protection.
EMT Conduit is thin-wall, galvanized steel tubing used to protect and route electrical conductors. Electricians bend and join EMT with listed fittings instead of threading the tubing. The metal pathway provides physical protection and may serve as an equipment grounding path when installed correctly under applicable electrical codes.
Fuse Box is an electrical enclosure that holds fuses protecting branch circuits from excessive current. Each fuse contains a metal element that melts when current exceeds its rating. Opening the circuit and stopping power flow. Fuse boxes were common in older homes before circuit breaker panels became the usual choice for residential electrical systems.
Ground Fault Circuit Interrupter is a protective device that monitors current flowing through a circuit’s ungrounded and grounded conductors. It trips when the outgoing and returning current differ. Often because electricity is leaking through a person or wet surface. The device disconnects power quickly to reduce shock and electrocution risk.
Insulation Resistance is the opposition that electrical insulation presents to unwanted current flow between conductors or between a conductor and ground. Technicians measure it in ohms, often in megohms, with a special tester called a megohmmeter. A high reading usually indicates sound insulation, while a low reading can signal moisture, damage, contamination, or aging.
Junction Box is an approved enclosure that protects electrical wire connections, cable splices, and branch-circuit junctions. The enclosure keeps energized conductors covered, limits contact with dust or moisture, and provides access for inspection and maintenance. Junction boxes may be metal or nonmetallic and must match the wiring method, location, and circuit requirements.
Kilowatt is an unit of power equal to 1,000 watts. Electrical equipment uses kilowatts to show how quickly the equipment consumes or produces energy. A kilowatt rating helps you compare appliance demand, size circuits, estimate operating costs, and assess whether a building’s electrical service can support connected loads.
Load Calculation is a method for determining how much electrical power a building, panel, or circuit may need during normal and expected peak use. The process considers connected equipment, demand factors, voltage, amperage, motor loads, heating systems, and future equipment. Electricians use the result to size conductors, breakers, panels, and service equipment safely.
NEMA is the National Electrical Manufacturers Association, a trade group that publishes standards for electrical equipment, enclosure protection, and wiring devices. NEMA ratings describe how enclosures resist hazards such as dust, water, oil, corrosion, or physical contact. NEMA also identifies standardized plug, receptacle, and connector configurations used in homes, commercial buildings, and industrial facilities.
Neutral Wire is the grounded conductor that normally carries current back to the electrical source after power flows through a load. It connects to the neutral bar in a service panel and commonly operates near 0 volts relative to ground. A neutral wire is not the same as an equipment grounding conductor. Which provides a safety path during faults.
Overcurrent Protection is a safety method that limits electrical current when a circuit carries more amperage than its wiring or equipment can safely handle. Circuit breakers and fuses provide this protection by opening the circuit during overloads or short circuits, reducing the risk of damaged conductors, fire, and equipment failure.
Panel Upgrade is the replacement or modification of an electrical service panel to increase capacity, improve circuit protection, correct unsafe conditions, or support new electrical loads. The work may include a larger panel, new breakers, service conductors, grounding changes, and updated labeling. A licensed electrician must assess the existing system before selecting equipment.
Photovoltaic System is an electrical power system that converts sunlight into direct-current electricity through semiconductor cells. The system typically includes solar modules, inverters, mounting equipment, wiring, disconnects, and protective devices. An inverter changes direct current into alternating current for building loads, battery storage, or delivery to the utility grid.
Plastic Conduit is a nonmetallic raceway that protects and routes insulated electrical conductors. It is commonly made from PVC or other approved polymers and is available in rigid or flexible forms. Plastic conduit resists corrosion, weighs less than metal conduit, and requires fittings designed for the specific conduit type and installation environment.
Power Factor is the ratio of useful real power to total apparent power in an alternating-current system. Expressed as a number from 0 to 1. It shows how effectively electrical current produces work. A factor of 1.0 is ideal. While a lower value means more current is needed for the same useful output.
Receptacle is a wiring device that provides contact points for a plug and connects electrical equipment to a branch circuit. A receptacle may include grounding, tamper-resistant, weather-resistant, GFCI, or AFCI protection. Standard household receptacles commonly serve 120-volt loads, while specialized designs support higher voltage, current, or specific plug configurations.
Residential Electrical Code is the set of safety rules that governs electrical wiring, equipment, circuits, and installations in homes. The rules address conductor sizing, grounding, overcurrent protection, receptacles, lighting, and required protective devices. Local authorities enforce the adopted code through permits and inspections. While the National Electrical Code provides the primary technical model.
Romex Cable is a common trade name for nonmetallic-sheathed electrical cable used in residential and light commercial wiring. The cable contains insulated current-carrying wires, plus a bare or insulated grounding wire, inside a flexible plastic jacket. Electricians install Romex Cable through framed walls, ceilings, and other protected spaces according to circuit ratings and electrical code requirements.
Short Circuit is an unintended connection between conductors that creates a low-resistance path for electric current. The path may bypass the normal load. Causing current to rise sharply. Excess current can produce heat, sparks, equipment damage, fire, or electric shock. A fuse or circuit breaker should interrupt the fault quickly.
Surge Protector is a device that limits short-duration voltage spikes on an electrical circuit. The device redirects or absorbs excess energy before the energy reaches connected equipment. Common forms include plug-in power strips with surge protection and whole-house surge protective devices installed at an electrical panel. Protection speed depends on design, ratings, grounding, and condition.
Thermal Imaging is a method that detects infrared radiation and converts temperature differences into a visible image. Electricians use a thermal camera to find unusual heat at panels, breakers, terminals, cables, motors, and other equipment. The image helps locate possible electrical faults without touching energized parts, but it doesn't replace electrical testing or inspection.
Transformer is an electrical device that transfers energy between circuits through a changing magnetic field. A transformer can increase or decrease alternating-current voltage while keeping the frequency nearly unchanged. Power systems use transformers to reduce transmission losses, supply building voltage, isolate equipment, and match electrical loads with available power.
Voltage Drop is the reduction in electrical voltage that occurs as current travels through a conductor, connection, or other circuit component. The reduction results from electrical resistance and increases with longer wire runs, higher current, or undersized conductors. Excessive Voltage Drop can cause dim lights, motor problems, heat, and unreliable equipment operation.
Watt is the SI unit of power. Describing how quickly electrical energy is transferred or used. One watt equals one joule of energy per second. Electrical devices show watt ratings to indicate their power demand or output. A higher watt rating usually means faster energy use, but it doesn't directly measure voltage or current.
Wire Gauge is a standardized measurement of a conductor’s diameter and electrical capacity. The American Wire Gauge system assigns smaller numbers to thicker wires and larger numbers to thinner wires. Correct gauge selection depends on current, circuit voltage, conductor material, insulation rating, installation method, and allowable voltage drop.
