scope:

This specification covers circuit breakers with housing of insulating material for Naval shipboard use.

Circuit breakers (see 6.4.2) shall be of the types (see 6.4.28), current ratings, voltages, trip characteristics, and interrupting capacities with mounting bases as specified in 1.2.1 through 1.2.2. A circuit breaker rating shall be for 60 hertz (Hz), 400 Hz alternating current (ac) and direct current (dc) applications.

The type designation shall be in the following form, as specified (see 6.2.1): Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: Commander, Naval Sea Systems Command, SEA 55Z3, Department of the Navy, Washington, DC 20362-5101 by using the self-addressed Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter.

The type is identified by a three letter symbol and a number as shown in table I. The first letter identifies the operation and trip characteristic:

A denotes automatic trip at currents in excess of the specified rated values (see tables II, III, and IV).

N denotes the nonautomatic trip (cross-line interrupting switch). The letters LB denote low voltage circuit breakers.

1 denotes the circuit breaker has one pole. TABLE I. Type designation.

Type Operation Maximum trip element (or switch) rating amperes (frame size (see 6.4.5)) ---------------------------------------------------------- ALB-1 Automatic 50 NLB-1 Nonautomatic 50

The current rating is identified by a number followed by the letter A, which identifies the maximum continuous current rating (see 6.4.4) of the device in amperes. The symbol 5A, for instance, identifies a 5 ampere (ac or dc) continuous current rating.

intended Use: