| Ampere Interrupting Capacity (AIC)
| Also called “Interrupting Rating.” A rating of the amount of current that a protective device, such as a fuse or circuit breaker, can safely interrupt. |
| Bolt-On
| A type of circuit breaker that is bolted into place. Generally found in commercial and industrial applications. |
| Branch Circuit
| A circuit that supplies power to the electrical loads in a building and is terminated at a distribution device (panelboard, loadcenter, etc.). |
| Bus Bars
| A component of a distribution device (loadcenter, panelboard, etc.) that serves as an extension of the main service conductors. Simplifies the connection of branch circuit breakers to the main service conductors. |
| Circuit Breaker
| An overcurrent protection device. After tripping to break the circuit, it can be reset to protect the circuit again. |
| Distribution Section
| Section of a meter breaker or multiple metering device where power is divided to tenant feed branch circuits. |
| Fusible Switch
| A disconnect switch with an integrated fuse. When the current passing through it exceeds a certain amperage, the fuse blows, breaking the circuit. |
| Group Metering
| Multiple metering unit commonly used in residential and commercial applications as service entrance equipment. It is modular in format to create customized lineups. |
| Horn Bypass
| An accessory used on ringless style metering stacks to provide uninterrupted power in case the meter must be removed. |
| Jaws
| Mechanical devices used for holding an installed meter securely in place. |
| Kilowatt/Hour
| A unit of measurement for electrical power usage. One kilowatt/hour is the use of one thousand watts of electricity in one hour. |
| Knockouts
| Circular perforations in the top and bottom panels of an enclosure that can be removed to provide entrances and exits for feeder wires enclosed in conduit. |
| Lever Bypass
| An accessory used on commercial metering stacks to provide uninterrupted power in case the meter must be removed. |
| Loadcenter
| A wall mounted device that delivers electricity from a supply source to loads in light commercial or residential applications. |
| Main Breaker
| An overcurrent protection device designed to protect an entire loadcenter, panelboard or switchboard. Power from the main service conductors is fed through a main breaker to the bus bars. |
| Main Service Conductors
| Also “Mains.” The conductors that bring electricity into a building from the power source. |
| Main Service Module
| Component of group metering. Provides a utility service termination point. Also contains a means of disconnection for the tenant breakers. |
| Main Terminal Box
| A main device available on 400-1600 amp main service modules. Consists of an enclosure with main lugs or terminals. |
| Manual Bypass
| An accessory used on ring-type style metering stacks to provide uninterrupted power in case the meter must be removed. |
| Measuring Device
| Component of a meter. A numerical readout allows the utility to measure the amount of power used. |
| Meter
| Shortened form of the term “watt/hour meter.” |
| Meter Breaker
| A metering device with is a single meter socket and a loadcenter, combined into one rainproof enclosure for convenience. |
| Meter Pack
| A stand-alone multiple metering unit commonly used in residential applications as service entrance equipment. |
| Meter Socket
| Mounting point for a watt/hour meter. |
| Metering Stack
| Component of group metering. Device consisting of one to six meter socket positions, vertically mounted in a single enclosure. |
| Multiple Metering System
| A metering system for use on multi-tenant buildings. Less complicated than using multiple single meter sockets. |
| NEMA
| Abbreviation for National Electrical Manufacturers Association. An organization of manufacturers of electrical products. |
| Phase Balancing
| The act of adjusting the phase jumpers of some metering stacks in three-phase group metering to spread the load evenly across the three power phases. |
| Plug-In
| A type of circuit breaker that is literally plugged into the bus bar stabs. Generally found in residential applications. |
| Pole
| Refers to the number of conductors or wires that the circuit breaker disconnects at one time. |
| Ring-Type
| A type of meter construction in which a ring secures the meter in place to prevent unauthorized entry. |
| Ringless
| A type of meter construction in which the socket has a drawn ridge around the cover. This ridge captures the cover and secures it in place to prevent unauthorized entry. |
| Series Ratings
| A statement of the AIC ratings of group metering components. |
| Service Entrance
| The point at which electrical power enters a building. |
| Six Handle Rule
| An NEC ruling which states that you must be able to throw no more than six handles into the off position to disconnect all electrical service. |
| Tenant Breaker
| The line on which power enters a tenant unit, upstream of the tenant unit’s distribution device (loadcenter, panelboard, etc.), downstream or part of the multiple metering equipment. |
| Voltmeter
| A device used to measure voltage by finding the potential voltage between two points. |
| Watt/Hour
| Standard unit of measurement for electrical power usage. One watt/hour is the use of one watt of electricity in one hour. |
| Watt/Hour Meter
| A device used for measuring electrical power usage. |
