B-O-N - Bay-O-Net; under-oil expulsion fuse cutout; a device whose mechanics represent a stab-sheath arrangement to hold an expulsion fuse; a device that provides a simple means of replacing an internal under-oil fuse in the field.

Back-up Current Limiting Fuse - A current-limiting fuse capable of interrupting all currents from its rated maximum interrupting current down to its rated minimum interrupting current as specified by the manufacturer; defined by ANSI C37.40-1981 or latest issue.

Basic Insulation Level (BIL) - a reference insulation level expressed as the impulse crest voltage of the nominal 1.2 X 50 microsecond wave. This is a measure of the ability of the insulation to withstand very high voltage surges.

Bathroom - A room containing bathing or showering facilities and may also contain a wash basin(s) and/or water closet(s).

Battery - a device with the ability to store a long term DC charge:

Sealed Cell - a storage battery that has no provision for the addition of water or electrolyte or for the external measurement of electrolyte specific gravity.

Storage - a battery consisting of more than one rechargeable cell of the lead-acid, alkaline, or other electrochemical types.

Bonding - A low impedance path obtained by permanently joining all non-current-carrying metal parts to assure electrical continuity and having the capacity to conduct safely any current likely to be imposed on it.

Bonding Conductor - A conductor which connects the non-current-carrying parts of electrical equipment, raceways, or enclosures to the service equipment or system grounding conductor.

Box Connector - See definition for Connector.

Branch Circuit - The portion of the wiring installation between the final overcurrent device protecting the circuit and the outlet(s).

Breakdown Voltage - Voltage at which material fails.

Building - A structure which stands alone or which is cut off from adjoining structures by fire-walls, unpierced or with openings, protected by approved fire-doors.

Bus - A conductor which serves as a common connection for the corresponding conductors of two or more circuits.

Busway - A raceway consisting of metal troughing (including elbows, tees, crosses, in addition to straight runs) containing conductors, the conductors being supported on insulators.