Brochure

PowerPact H-, J-, and L-Frame Circuit Breakers
Installation Recommendations
151
02/2016
© 2011–2016 Schneider Electric
All Rights Reserved
PowerPact H-, J- and L-Frame Circuit Breakers Equipped with Electronic Trip Units
Electronic trip units are not affected by variations in temperature. If the trip units are used in high-
temperature environments, the Micrologic™ trip unit setting must nevertheless take into account the
temperature limits of the circuit breaker.
Changes in temperature do not affect measurements by electronic trip units.
• The built-in CT sensors with Rogowski coils measure the current.
• The control electronics compare the value of the current to the settings defined for 104°F (40°C).
Because temperature has no effect on the CT measurements, the tripping thresholds do not need to
be modified.
However, the temperature rise caused by the flow of current combined with the ambient temperature
increases the temperature of the device. To avoid reaching the thermal withstand value, it is necessary
to limit the current flowing through the device, that is the maximum I
r
setting as a function of the
temperature.
The table below indicates the maximum long-time (LT) protection setting I
r
(A) depending on the
ambient temperature.
Example. A unit-mount PowerPact L-frame circuit breaker equipped with a Micrologic can have a
maximum I
r
setting of:
• 400 A up to 122°F (50°C)
• 380 A up to 140°F (60°C)
Table 138: Derating Circuit Breakers with Micrologic Trip Units
Temperature
Type of Device Rating
104°F
(40°C)
113°F
(45°C)
122°F
(50°C)
131°F
(55°C)
140°F
(60°C)
149°F
(65°C)
158°F
(70°C)
H-Frame
Unit-mount, plug-in or drawout
60 A No derating
100 A No derating
150 A No derating
J-Frame
Unit-mount 250 A 250 250 250 245 237 230 225
Plug-in or drawout 250 A 250 245 237 230 225 220 215
L-Frame
Unit-mount 400 A 400 400 400 390 380 370 360
Plug-in or drawout 400 A 400 390 380 370 360 350 340
Unit-mount 600 A 600 600 600 585 570 550 535
Plug-in or drawout 600 A 570 550 535 520 505 490 475