MIL-DTL-23928G
3.4.3.5 Electrical connections. Electrical connections to bus bars shall be secured by means of through bolts and
nuts rather than by screws tapped into the bus bars except the connections may be tapped into a steel insert force-
fitted into the bus bar. When a steel insert is used, the decrease in cross-section of the bus shall decrease the rated
current carrying capacity of the bus (see table II).
3.4.3.6 Grounding bus or stud. When specified (see 6.2), types ALB-1 and AQB-A50 panels supplying electronic
equipment shall have an equipment grounding bus or stud installed in the panel. The bus or stud shall be of a size
suitable for connecting a ground conductor between the panel and the ground terminal for each electronic equipment
supplied.
3.5 Performance characteristics.
3.5.1 Level of effectiveness of enclosure. The panels shall perform their designed function when tested as
specified (see 4.5.2). Following the test, the panels shall pass the dielectric strength test (see 4.5.7). The watertight
and submersible class panels shall show no signs of water leakage.
3.5.2 Temperature rise. Temperature rise in current carrying parts (bus bar connection points and terminals) shall
be not greater than 45°C when tested as specified (see 4.5.3); the panel interior ambient temperature shall be not
greater than 65°C.
3.5.3 Short circuit. The panels shall be serviceable after short circuit testing as specified (see 4.5.4). They shall
show no signs of damaging distortion to bus work, holders, securing devices, and bases.
3.5.4 Vibration. The panels shall pass the type I vibration tests specified (see 4.5.5). Any of the malfunctions
listed in 3.5.7 shall be cause for test failure. Following the vibration test, the panels shall pass the dielectric test as
specified (see 4.5.7).
3.5.5 Salt atmosphere. When the specified application (see 6.2g) of the panels exposes them to a salt atmosphere
(e.g. exposed weather deck, well deck environment), CRES or other suitable corrosion resistant construction
material, meeting the requirements specified herein, shall be used. The panels shall be tested in accordance with
4.5.6 and shall show no evidence of excessive corrosion. Excessive corrosion is defined as corrosion that interferes
with electrical or mechanical performance, or, in the case of plated metals, corrosion that has passed through the
plating and attacked the base metal. Where corrosion-resisting treatments are used, limited superficial corrosion
which would result from scratches is permitted.
3.5.6 Dielectric strength. Panels shall show no evidence of arcing (other than at test probes), corona (visible,
audible, or smell), flashover, or punctured insulation when subjected to the standing voltage tests as specified (see
4.5.7). Any such indications shall be cause for test failure.
3.5.7 Shock. Panels shall be subjected to the shock tests specified (see 4.5.8). Any of the following malfunctions
shall be cause for test failure:
a.
Contact between live parts or between live parts and the enclosure during the test.
b.
Door opens.
c.
Structural parts damaged or loosened.
d.
Functional parts such as breaker mounting bases and bolts damaged or loosened.
e.
Circuit breakers shall not change position/state from "on" to "off", from "off" to "on", or from "on" to "trip"
during the test. An "off" to "trip" position/state change is permitted.
f.
Any closing of circuit breaker main and auxiliary contacts from the open position shall not be acceptable.
g.
Momentary opening of circuit breaker main and auxiliary contacts shall not be in excess of 0.020 seconds
during a single shock event.
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