Aluminum wiring is often used for the service entrance conductors and for large gauge wiring to major appliances such as electric clothes dryers, central air-conditioning, electric oven, etc. Aluminum wiring for such applications is quite satisfactory; however, aluminum wiring installed as branch circuits for general lighting, electrical switches and receptacle outlets, small appliances, etc. may be hazardous and certain modifications are recommended for these applications.
Amperes, or amps, is a measure of the capacity of an electrical system. The typical minimum requirement is 100 amps; if a home is larger, or has central air-conditioning or electric heat, 150 to 200 amps is recommended.
A branch circuit is the wiring from a fuse or circuit breaker in an electrical service panel that provides electricity to particular electrical switches, outlets, junction boxes, etc.
BX wiring, or armored cable, is a type of wiring that is installed in a house. This type of wiring is enclosed in a metallic sheathing and is more resistant to damage than Romex wiring.
An electrical circuit is a flow of electricity from a supply source to one or more terminals, such as electrical outlets, switches, appliances, etc.
An over current protection device that is designed to automatically cut off the flow of electricity when the flow of current through the circuit breaker exceeds its rated capacity. Unlike most fuses which require replacement when they are overloaded, a circuit breaker can be reset much like a switch.
A conductor is a wire that conveys electricity.
Copper wiring is the most common type of metal used for wiring and can be either BX or Romex or enclosed in conduit.
Doubled Up Conductors
One conductor should be terminated on a service panel fuse or circuit breaker lug unless the lug is specially designed to accept more than one conductor; all improper double connections must be eliminated by a licensed electrician by relocating the affected conductors to a new position in the service panel.
Ground Fault Circuit Interrupter
Ground fault circuit interrupters, GFCI units, are installed in areas that are subject to water, such as bathrooms, kitchens, garages, unfinished basements, outdoors, etc. GFCI units are designed to protect persons from hazardous ground faults by automatically turning off the electricity to the unit when a fault is detected.
An over current protection safety device that is designed to automatically cut off the flow of electricity when the flow of current through the fuse exceeds its rated capacity.
Electrical systems must be properly grounded to provide a safe service. System conductors are typically secured to driven ground rods or water service pipes.
Knockouts, or twist outs, in an electrical service panel should not be removed unless the position is filled; missing knockouts present a safety hazard if a person places a finger into the the service panel through the knockout. Therefore, all missing knockouts should be replaced with plastic fillers or with circuit breakers.
Knob-and tube wiring is an outdated type of wiring that has been replaced by Romex and BX wiring. This outdated type of wiring can be hazardous and replacement with modern wiring is typically recommended.
An electrical receptacle outlet with an open ground condition is an outlet with an improper wiring condition and such conditions may be hazardous and repair is required.
Open Junction Box
Electrical junction boxes must have proper covers; when a junction box does not have a cover, it is noted as an open junction box.
Over Fused Circuit
An over fused circuit is a circuit that is protected from over current by a fuse or circuit breaker that is over sized for the capacity of the circuit conductors. This is a hazardous condition that can result in overheating of the conductors and may result in an electrical fire.
An overhead electrical service is a service where the conductors approach a home overhead.
Over Loaded Circuit
An overloaded circuit is a branch circuit that has too many electrical outlets, switches, etc. connected to it and therefore, the fuse or circuit breaker associated with this circuit is likely to trip. An overloaded circuit may have to be split into two circuits if the fuse blows, or the circuit breaker trips too often.
An electrical receptacle outlet with a reversed polarity condition is an outlet with an improper wiring condition and such conditions may be hazardous and repair is required.
Romex wiring, or nonmetallic sheathed wiring, is a type of wiring that is installed in a house. This type of wiring is widely utilized but is less resistant to damage than BX wiring.
The conductors and equipment for delivering electricity from the electrical supply system to the wiring system of a house.
The overhead service connectors from the utility pole to the house.
The service panel is the center of the electrical service in the house; the service panel is the location of the electrical circuit breakers or fuses.
An improper connection between the hot and neutral wires of a circuit can result in a short circuit defect.
An underground electrical service is a service where the conductors approach a home underground.
Most home wiring is 110 volts; 220 volts is utilized for large appliances such as electric ranges, electric clothes dryers, central air-conditioning, large room air-conditioners, etc.
The weather head is the connection between the service drop from the utility company and the service entrance conductors.
Definition of Electrical Terms
Alternating Current (AC): An electric current that reverses direction in a circuit at regular intervals. Alternating current, also called AC, is used in almost all homes and buildings today.
Aluminum Wiring: Houses and buildings built between 1965 and 1973 may have been wired with aluminum a potential fire hazard.
Amps: The unit of measure of the flow rate of current.
Circuit Breaker: A device that shuts of a circuit by mechanical action when too much current is flowing. When a high current passes through a circuit breaker a trigger rapidly separates a pair of internal contacts. Unlike a fuse which must be replaced after it has blown once, a circuit breaker can be reset after it has been tripped. Circuit breakers have replaced fuses in modern buildings.
Circuit Breaker Panel: An electric panel containing circuit breakers.
Conductor: A substance, typically metal, that conducts an electric current. Copper and aluminum are the most common conductors in building wiring.
Current: The rate of flow of electrons, measured in amps. The more electrons flowing, the more energy that is available. However, the flowing electrons heat up the wire. Too much heating of the wire creates a fire hazard.
Direct Current (DC): An electric current that flows in one direction in a circuit. Direct current, also called DC, is rarely used homes and buildings today.
Fuse: A safety device used to protect against excessive current. A fuse consists of a metal alloy strip with a low melting point. Because of its electrical resistance, the alloy strip is heated by electric current. If the current exceeds a safe value, the strip melts and stops the current. Fuses are rarely seen in modern wiring.
Insulation: A material that does not conduct electricity. A conductor wrapped in insulation forms the wiring found in homes and buildings. Most modern insulators are plastic or vinyl.
Power: As a first order approximation, power is the product of the voltage times the current. Power is a measure of how much work can be done in a certain period of time. It is power (not voltage or current) that defines how much work is actually done.
Sub-Panel: An additional electrical panel installed after the main circuit breaker panel.
Three-Phase Power: Electrical power delivered in three separate phases. This is the way electrical power is distributed throughout the community and supplied to buildings.
Voltage: The electrical energy available, measured in volts.
Volts: The unit of measure of electrical potential.
Watt: A unit of measure of electric power.
Wire: A conductor surrounded by an insulator. Wires carry the electric current throughout a building.