ELECTRICAL TERMS

Ballast
Circuit
Circuit Breaker
Efficiency
Junction Box
Line Voltage Bulb
Low Voltage Bulbs
Transformer
Voltage
Voltage Drop
Wattage

Ballast: An electrical device for fluorescent light sources that is typically located in the fixture. The ballast provides the high initial current that starts the fluorescent lamp (called "striking an arc") and then delivers the correct current to maintain the arc in the lamp. Ballasts must match the lamp type and wattage to assure proper operation.

Circuit: A closed path of electricity. A circuit in the home includes a breaker or fuse, the wiring, and the load.

Circuit Breaker: A circuit breaker (or fuse) protects a circuit from being overloaded.

Efficiency: Relates light output (lumens) to the electric power required to produce it (watts). Measured as lumens per watt. Light source efficiency is the best measure of the lifecycle cost.

Junction Box: A metal or plastic enclosure, in which wires are joined or spliced. Surface-mounted fixtures attach to junction boxes. Junction boxes must be accessible.

Line Voltage Bulb (or lamp): Operates directly off the household current, nominally 120 volts. Most incandescent light sources for general and decorative lighting are line voltage. Available in 120 volt or 130 volt (typically used in commercial applications).  You can dim line voltage bulbs lights with basic, inexpensive dimmers.

Low Voltage Bulbs (or lamps): Operate at a reduced voltage, most often at 12 volts. A transformer is required as part of the fixture or the current to change the 120 volt household current to the lower 12 volts that drives the lamp. The chief benefit is the ability to make the light source very small, and deliver a precise beam of light. Low voltage systems are most often used in accent and landscape lighting.

Transformer: Device that is required to convert one level of voltage to another.

Voltage: Measures the electrical "pressure" that creates a current. Electric utilities distribute power efficiently over long distances at high voltage. Transformers reduce the voltage to safe and practical levels for household use. Most lighting and household appliances operate at 110-120 volts. Heavy appliances use 220-240 volts.

Low voltage is defined as less than 30 volts. Most low voltage lighting operates at 12 volts.

Voltage Drop: Negative effect that Occurs as an electrical current travels over extensive lengths of relatively small conductors. Voltage drop will dim the lights at the end of the wiring relative to the rest of the circuit.

Wattage: Watts measure electrical power. Wattage is the product of voltage and amperage.