Electrical equipment installations shall as a minimum comply with NFPA 70. Electrical systems
shall be provided in accordance with the electrical engineering criteria manuals and this
Hangar (OH) Space
The maintenance hangar (OH) space shall be designed to meet the criteria set forth below.
Electrical equipment in the hangar (OH) space should be waterproof, NEMA Type 4 (minimum
rating) when deluge sprinkler protection is provided to prevent equipment damage in the event of
testing or accidental discharge of the deluge system.
Areas in high bay space shall be classified as hazardous or non-hazardous in accordance with
NFPA 70. All electrical installations shall meet applicable requirements. To the extent possible,
electrical installations should not be located in hazardous zones.
Power Service Points
MIL-HDBK-1028/6 identifies the various types, the capacity, and the location and installation
requirements of electrical power to be provided at the power service points. Aircraft power
service points should be positioned as required to provide adequate connections to aircraft to be
maintained in the hangar. The power service points will provide:
a) Three phase, 115/200V, 4 wire, 400 Hz, (kVA ratings shall be as required by
b) Three phase, 100 Amp, 480 V, 4 wire, 60 Hz, with (Class L) receptacles for
GSE. Special purpose receptacles designed to mate with standard government equipment shall be
Military Part Number MS90555C44152P. This receptacle is built by very few manufacturers and
shall be indicated as such. Designer shall coordinate required outlet requirements with the using
c) Single phase, 120 V, 60 Hz, ground fault interrupt duplex utility outlets.
d) 28 V direct current (kVA ratings shall be as required by aircraft type)
e) External aircraft power provided by the power service points must be within the
voltage and frequency tolerances specified for aircraft type. The flexible power cable to the
aircraft must be adequately sized to meet the specified aircraft loading (amperage) requirements.
Spiral wrapped, six around one, flexible cables, designed specifically for 400-hertz systems
should be considered.