MIL-STD-1399 Ship Interface Tests

MIL-STD 1399 is a military standard approved for use by the Navy Department Naval Marine Systems Command and can be used by all Departments and Agencies of the Department of Defense. The purpose of MIL STD 1399 is to define standard interface requirements and restrictions applicable to the design of shipboard user equipment that will use alternating current (AC) electrical power on board.

MIL-STD-1399 lists the Nature of the Interface as follows:

In any system that includes a power supply, distribution network, and load (user equipment), the features at the system and user equipment interface are mutually dependent on the design and operation of both. In order for the electrical power system to operate within specified tolerances, restrictions must be placed on the power supply, distribution system and user equipment. This interface standard defines electrical power system specifications. User equipment restrictions are also set.

MIL-STD-1399 lists the build as follows:

The technical content first describes the characteristics of the onboard electrical power system at the interface in terms of voltage, frequency, continuity and voltage waveform. The constraints on the design and installation of user equipment necessary to ensure and ensure compliance with these specifications on board are then determined. Finally, testing requirements are specified to verify compliance with this standard.

MIL-STD-1399 lists the build as follows:

This section specifies electrical interface specifications for shipboard equipment that uses AC electrical power to ensure compatibility between the user equipment and the electrical power system. Characteristics of the electrical power system are defined and tolerances are set. User equipment shall operate from a power system with these characteristics and shall be designed within these constraints to reduce adverse effects of user equipment on the electrical power system. Test methods are included to verify compatibility.

The types of ship electrical power to be supplied from the MIL-STD-1399 electrical power system are as follows:

• Type I: Type I power is 440 or 115 volts (V), 60 hertz (Hz) ungrounded and is the standard ship electrical power supply. Type I power will be used unless a deviation is provided (see 4.3).
• Type II: Type II power 440 or 115 V, 400 Hz is ungrounded and has only limited application. Use of type II power requires submission and approval of a deviation request (see 4.3).
• Type III: Type III power 440 or 115 V, 400 Hz is ungrounded and has tighter tolerances compared to Types I and II. Type III power is restricted in its use and requires submission and approval of a deviation request (see 4.3).

MIL-STD-1399 also specifies a specific power classification for the types of onboard electrical power provided only for avionic shops and aircraft service. Specific power classifications are as follows:

• Type I: Type I power is 115/200 V, 60 Hz, 3-phase, 4-wire, Wye grounded. This power is provided for avionics shops only.
• Type III: Type III power 115/200 V, 400 Hz, 3-phase, 4-wire, Wye grounded. This power is provided for avionics workshops and aircraft service only.

MIL-STD-1399 is periodically revised. Current versions of the standard include MIL-STD-1399 C, MIL-STD 1399 B, and MIL-STD 1399 A.