MIL-DTL-917F(SH)
3.2.10 Grounding. See 6.5.4.
3.2.10.1 Electrical grounding. Electrical equipment operating from an ungrounded power system shall not
malfunction if the power system is accidentally electrically grounded or if the power system is connected to ground
(hull) by means of high impedance electromagnetic interference suppressor circuits. The equipment shall not
impose a ground upon the ship power system, and any equipment which employs internal grounding shall be
isolated from the ship power system by means of transformers or separate generator sets. Equipment chassis,
equipment enclosure, or the ship hull shall not be used in lieu of appropriate electrical conductors as the equipment
circuitry. Circuit grounds necessary for built-in ground detection circuits are excluded from these requirements.
3.2.10.2 Exposed metal or other conductive parts. Design and construction of the equipment shall be so that all
exposed parts or panels of metal or other electrically conductive material are at ground (ship's hull) potential at all
times in accordance with MIL-STD-1310. Exposed metal portions of electrical parts (switches, rheostats, and so
forth) or other parts located near electrical circuits (including parts inside enclosures where access is required for
operation or adjustment) shall be in intimate physical contact with the frame of the equipment or electrically
connected to the frame if these parts could touch the electrical circuits as a result of deformation, wear, insulation
failure, and so forth.
3.2.11 Surge (indicated as spike) voltage suppression. Unless otherwise specified (see 6.2), equipment shall be
designed to operate on input power containing voltage spikes in accordance with MIL-STD-1399-300. Equipment
shall be protected against part failure or malfunction due to voltage spikes occurring randomly on the input power
source.
3.2.11.1 Parts stress limitation. Equipment which employs circuits and parts in such a way that this degree of
protection is not inherently achieved shall provide protection by use of spike voltage suppressors or suppression
circuitry in accordance with MIL-PRF-32167. Likewise, where equipment is subject to use with power supply or
load systems which may supply or produce surge voltages higher than the values specified in 3.2.11, the equipment
shall withstand these higher spike voltage stresses (see 3.2.9). Voltage regulator diodes and controlled-avalanche
types of rectifier diodes, complying with the requirements specified in 3.13.18, may be used for spike voltage
suppression. Also, spike voltage suppressors specified in 3.13.19 may be used for this purpose. All parts which
may be subjected to application stresses due to interaction capabilities of circuits, minimum to maximum
adjustments, or other deleterious circuit effects that could result from ill-advised sequencing or combinations of
prescribed personnel actions shall be of a type, size, design, and performance capability, as applied, that will not be
damaged by these stresses (see 3.13.1.1). All parts shall be a type, size, and design that any combination of circuit
elements or adjustments shall not induce stresses which will cause damage to the equipment.
3.2.12 Inclined operation. Unless otherwise specified (see 6.2), equipment shall perform satisfactorily during
inclined operation in accordance with design limits for surface ship and submarine motion specified in
DOD-STD-1399-301.
3.2.13 Temperature and humidity.
3.2.13.1 Temperature. The equipment shall perform reliably and in accordance with specified performance
requirements of the equipment throughout the applicable operating temperature range specified (see 6.2).
Equipment shall not be damaged nor shall the operational performance be degraded when the equipment is restored
to the operating temperature range after having been exposed for long periods in the non-operating ambient
temperature range as specified in table I. If exterior shipboard service is intended, this shall be specified in the
contract (see 6.2). If not so specified, equipment shall be designed for interior shipboard services.
19
For Parts Inquires submit RFQ to Parts Hangar, Inc.
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business