09/2005
QOU Miniature Circuit Breakers and Switches
Application Information
Table 1: Selection Data
Catalog Number
Rating
One-Pole
120/240 Vac
10K AIR
22K AIR
Two-Pole
120/240 Vac 240 Vac
10 K AIR
120/240 Vac
22K AIR
Three-Pole
240 Vac
10K AIR
Terminal
Lug Wire
Size (AWG)
10 A
QOU110
—
QOU210
—
QOU310
15 A
15 A
QOU115*
QOU115HM*†
QOU115VH
—
QOU215*
—
QOU215H*
—
QOU215VH
QOU315*
—
20A
20 A
QOU120*
QOU120HM*†
QOU120VH
—
QOU220*
—
QOU220H*
—
QOU220VH
QOU320*
—
25 A
QOU125*
QOU125VH
QOU225*
QOU225H* QOU225VH
QOU325* 1—#14–#2
30 A
QOU130*
QOU130VH
QOU230*
QOU230H* QOU230VH
QOU330* Cu or Al
35 A
QOU135*
QOU135VH
QOU235*
—
QOU235VH
QOU335*
40 A
QOU140*
QOU140VH
QOU240*
—
QOU240VH
QOU340*
45 A
QOU145*
QOU145VH
QOU245*
—
QOU245VH
QOU345*
50 A
QOU150*
QOU150VH
QOU250*
—
QOU250VH
QOU350*
60 A
70 A
80 A
90 A
100 A
125 A
QOU160*
QOU170*
QOU180‡
QOU190‡
QOU1100‡
—
QOU160VH
—
—
—
—
—
QOU260*
QOU270*
QOU280‡
QOU290‡
QOU2100‡
QOU2125‡
—
QOU260VH
QOU360*
—
—
QOU370‡
—
—
QOU380‡
—
—
QOU390‡ 1—#12–#2/0
—
—
QOU3100‡ Cu or Al
—
—
—
Switch—60 Amperes Max.—240 Vac
Switch—100 Amperes Max.—240 Vac
Switch—125 Amperes Max.—240 Vac
QOU200
QOU2000‡
QOU20001‡
QOU300
QOU3000‡
QOU30001‡
1—#14–#2
1—#12–#2/0
* UL Listed as HACR type for use with heating, air conditioning and refrigeration equipment containing motor-group combinations
and marked for use with HACR type circuit breakers.
† High-magnetic trip circuit breakers. Recommended for applications where high initial inrush current can occur and for individual
dimmer applications.
‡ Available as Series 1 with forward box lugs only. (No optional terminations)
Tripping Mechanisms
A tripping mechanism is an assembly within the circuit breaker molded case that causes the circuit
breaker to open automatically under sustained overload or short circuit conditions.
The tripping mechanisms in two- and three-pole circuit breakers operate such that an overcurrent on
any pole of the circuit breaker will cause all poles of the circuit breaker to open simultaneously.
Thermal and magnetic factory calibration (with current) is performed on each pole of every Square D
circuit breaker.
These mechanisms operate to trip the circuit breaker:
• Thermal trip
• Magnetic trip
• Optional shunt trip accessory (see Accessories, page 12)
The sensing system is an integral part of a thermal-magnetic circuit breaker. The sensing system
continually monitors current flowing through the circuit breaker. It detects abnormal current conditions
and, depending on the magnitude of the current, initiates an inverse-time or an instantaneous tripping
response. This action causes the tripping mechanism to open the circuit breaker contacts and interrupt
current flow. The speed of the tripping process must be controllable and inversely matched to the
severity of the overcurrent. QOU miniature circuit breakers have an over-center toggle mechanism for
quick-make, quick-break action with positive handle indication. The handle assumes a position
between ON (I) and OFF (O) when the circuit breaker has tripped.
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