MIL-DTL-17361G(SH)
3.5.18.2 Mounting arrangements (circuit breakers and fuse units). Current limiting fuse units shall be back-
connected (see 3.5.17.2). Circuit breakers shall be arranged for one of the following three connections between load
and power supply as specified (see 3.1 and 6.2).
a.
Front connected (see 6.4.9).
b. Back-connected (removable mounting only) (see 6.4.4 and 6.4.23). Back-connected circuit breakers and
current limiting fuse units shall permit easy removal from the front of a live switchboard or panel in which they are
mounted without need for access to rear of the switchboard or panel and without disturbing the connections or bus
work on the rear of the switchboard or panel.
c.
Combination (front connected to load and back-connected to the line side).
3.5.18.3 Circuit breaker/mounting base/block interface connections and mounting base/block stud terminals.
Slip-type connectors shall be provided on the rear of the circuit breaker to mate with the mounting base/block. The
connectors shall permit the ready removal of the circuit breakers or current limiting fuse units without using
insulated tools and accomplished by removing the supporting screws and drawing the circuit breaker or current
limiting fuse unit out. The female portion of each slip-type connector shall be sized to ensure full contact is
obtained with its corresponding male stud portion and shall be enclosed or otherwise protected when it is exposed in
order to prevent damage to these parts. Stud terminals shall be provided on rear-connected mounting bases/blocks
for rear-connection of cabling or bus bar.
3.5.18.4 Temperature rise. Temperature rise of circuit breaker slip-type connectors and mounting base/block
stud terminals shall not exceed 65 °C for equipment in as-new condition. As circuit breakers and attachments are
cycled and tested for qualification, temperature rise limits may vary. See 4.5.12 and Table V for these test
requirements.
3.5.19 Attachments. Attachments (see 6.4.2) shall include the electric operating mechanism, undervoltage
release device, shunt trip, auxiliary switch, handle locking device, and handle boot.
3.5.19.1 Temperature rise. Temperature rise of electric operating mechanisms, undervoltage release devices,
shunt trips, and auxiliary switches shall not exceed the requirements of molding and insulating materials specified in
MIL-E-917 in as-new condition. As circuit breakers and applicable attachments are cycled and tested for
qualification, temperature rise limits may vary. See 4.5.12 and Table V for these test requirements.
3.5.19.2 Endurance. During circuit breaker electrical endurance testing, electric operating mechanisms,
undervoltage release devices, and shunt trips shall have the ability to be cycled continuously for the applicable
number of endurance operations specified in Tables II, III (a), III (b), and IV. Rate of operations shall be as
specified for the circuit breaker electrical endurance test in the applicable specification sheet (see 3.1).
3.5.19.3 Electric operating mechanism. When specified (see 6.2), an electric operating mechanism shall be
provided. The attachment shall consist of an assembly including an opening and closing mechanism with its
associated devices for mounting on the front of a manually operated circuit breaker except for stored energy circuit
breakers where the attachment is internal rather than mounted on the front. The electric operating mechanism shall
have the following characteristics:
a.
Closing time of the electric closing mechanism at normal voltage shall not exceed 1/2 second.
b. When the circuit breaker trips, the operating mechanism shall be capable of relatching and returning the
circuit breaker closing mechanism to the off position.
c. The attachment shall not exceed the height dimensions of the circuit breaker type. The depth of the
attachment from the circuit breaker front surface shall not exceed 6-1/4 inches. The width dimension of the circuit
breaker type may be exceeded by 7/8-inch maximum on each side.
d.
Aluminum may be used wherever feasible to reduce the weight of the attachment.
e.
An identification plate shall be provided.
f.
The attachment shall pass the tests specified in 4.2.
g. The attachment shall be of open frame construction except that electrical contacts, relays, switches, or
brakes that could be affected by dust or other contamination shall be adequately protected.
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