restriction of access features. In types II, IV, VI, VII, IX, X, and XII
switchboards, provision shall be made for termination of large conductor ship
cables as necessary to energize the various switchboard loads (see 22.214.171.124).
3.6.29 Dielectric withstanding voltage and insulation resistance clearances.
Clearances between any two electrical circuits or between any electrical circuit
and ground (metal enclosure or chassis) shall meet the test conditions for dielec-
tric withstanding voltages specified in 4.6.3. The insulation resistance of the
circuits following the dielectric withstanding voltage test shall be not less
than 10 megohms when tested as specified in 4.6.4. Creepage and clearance
distances between conductors and other conductors, ground, or frame in the equip-
ment shall conform to those listed in requirement 69 of MIL-STD-454 and in no
case shall be less than that necessary to prevent arcing or leakage during opera-
tion or service.
3.6.30 Printed wiring boards. Printed wiring boards shall be in accord-
ance with MIL-STD-275 and MIL-P-13949. The requirements of MIL-P-55110 are
not applicable. Size of printed wiring boards shall be in accordance with those
specified in requirement 17 of MIL-STD-454.
3.7 Features - environmental and miscellaneous. The following environ-
mental and miscellaneous features are applicable to the switching equipment
3.7.1 The following requirements of MIL-STD-454 are applicable:
Requirement 1 - Safety (personnel hazard)
Requirement 62 - Human engineering
3.7.2 Shock. Equipment shall withstand the shock specified in 4.6.7,
without damage or distortion of sufficient magnitude to impair the operation
of the equipment contained therein. Minor derangements which do not cause
malfunction or inoperation shall be referred to NAVSEA for specific approval
of design consideration. Acceptance criteria shall be as specified in
MIL-S-901. This test shall be made after all other tests have been concluded l
126.96.36.199 During these tests, circuits as specified in the appendix shall
be energized to ensure continuity of the circuits through the switchboard.
Failure of the circuits to operate shall not be considered a failure of the
switchboard, provided failure was caused by failure of a part, rather than by
failure of switchboard wiring.
3.7.3 Vibration. Equipment shall withstand, without mechanical or
electrical damage, the vibration specified in 4.6.6. Acceptance criteria
shall be as specified in MIL-STD-167-1. During these tests, circuits as speci-
fied in the appendix shall be energized to ensure continuity of the circuits
through the switchboard. Failure of the circuits to operate shall not be
considered a failure of the switchboard, provided failure was caused by failure
of a part rather than any failure of switchboard wiring.