Specification

© 1998–2008 Schneider Electric
All Rights Reserved
QO
®
and QOB Miniature Circuit Breakers
General Information
6
07/2008
Temperature Rating
To meet the requirements of Underwriters Laboratories Standard 489, molded case circuit breakers
are designed, built, and calibrated for us on 60 Hz ac systems in 40°C (104°F) ambient temperature.
When applied at ambient temperatures other than 40°C, the current-carrying capacity and/or trip
charasteristics of the circuit breaker may vary.
IEC Rating
IEC rated QO circuit breakers are available. For further information contact the Field Sales office.
Terminology
HACR
HACR is a term used to designate circuit breakers which have been certified to be used on multi-motor
and combination loads such as are found in heating, air conditioning and refrigeration equipment. QO
circuit breakers meet the UL requirements for HACR circuit breakers and are suitable for group motor
applications requiring HACR listing.
This means that QO and QOB circuit breakers meet the code requirements that HACR circuit breaker
must be of the inverse time type and be approved for group installation. QO and QOB circuit breakers,
except for GFI, AFI and EPD, are Listed with UL as HACR Type and are labeled accordingly.
Figure 1: Ambient Rerating Curves
10
20
30
40
50
60
Current Carrying Capacity (A)
30 A
20 A
15 A
-10
(14)
0
(32)
20
(68)
40
(104)
60
(140)
Ambient Temperature
˚C
(˚F)
QOT Circuit Breakers
Circuit Breaker Handle Rating
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
Current Carrying Capacity (A)
100 A
90 A
80 A
70 A
15 A
10 A
30 A
20 A
40 A
60 A
50 A
110 A
125 A
-10
(14)
0
(32)
20
(68)
40
(104)
60
(140)
Ambient Temperature
˚C
(˚F)
QO, QOB Circuit Breakers
Circuit Breaker Handle Rating
25
50
75
100
125
150
175
200
225
250
275
Current Carrying Capacity (A)
200 A
175 A
150 A
125 A
-10
(14)
0
(32)
20
(68)
40
(104)
60
(140)
Ambient Temperature
˚C
(˚F)
Circuit Breaker Handle Rating
QE Circuit Breakers