19
Time current tripping characteristics
WavePro
™
low voltage power circuit breaker time current
curves are the engineering documents that define technical
performance characteristics of the devices. Multiples of
circuit breaker trip rating are shown on the top and bottom
h
orizontal axis, with time in seconds on the vertical axis.
Minimum and maximum clearing time is readily determined
through the characteristic curves. Tripping characteristics
meet ANSI, NEMA and UL standards for rating and calibration.
Table 19.1 Time current curves
Cable terminations
Cables used for low voltage power circuit breaker terminations
in AKD-10 must
have minimum 90°C insulation while the
cables’ ampacity will be based on a 75°C rating
. This meets
the requirements of ANSI C37.20.1, UL1558 and the National
Electrical Code. Refer to the example for typical cable
ampacities (derating factors that may apply are not shown).
Table 19.2 Example (from NEC Table 310.16)
Cable size 90°C rating (ref.) 75°C rating (of 90°C cable)
500kcmil 430 Amps 380 Amps
600kcmil 475 Amps 420 Amps
Trip device Trip elements Curve REF
Power+
™
MicroVersa Trip Plus
™
MicroVersa Trip PM
™
L
SI
D
ES-001
p
g. 20
G DES-002 pg. 21
MicroVersa Trip Plus
or PM
Non-std. G F DES-026 pg. 22
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