NOARK · UL 1066 Air Circuit Breaker
Product overview
NOARK A25 power circuit breakers provide low-voltage distribution protection for switchgear and customized power-distribution assemblies. The UL 1066 family supports 50/60Hz operation and 3-pole or 4-pole construction. This page covers the protective A-series breaker, with the matching trip unit specified as part of the complete assembly.
Technical selection summary
| Manufacturer / series | Original NOARK A25; North American UL family |
|---|---|
| Approvals / standards | UL 1066; CSA C22.2 No.268; ANSI C37.13 / C37.16 / C37.17 / C37.50, as stated in the manufacturer catalogue |
| Frame current | 600A, 800A, 1200A, 1600A, 2000A, 2500A |
| Poles | 3P or 4P |
| Mounting / terminal codes | F: fixed; D: drawout; H: horizontal rear terminals; V: vertical rear terminals |
| Mounting restrictions | 2500A: fixed with vertical terminals only; drawout maximum 2000A. |
| Rated maximum voltage | 254 / 508 / 635 / 847Vac; apply the interrupting rating at the actual voltage |
| Interrupting rating at 254/508Vac | Q: 65kA; R: 85kA; H: 100kA |
| Interrupting rating at 635Vac | Q: 65kA; R: 75kA; H: 85kA |
| Interrupting rating at 847Vac | Q: 65kA; R: 75kA; H: 85kA |
| Frequency | 50Hz / 60Hz |
| Trip protection | LI, LSI or LSIG; select the matching separately ordered trip unit and rating plug |
| Dimensions and connections | See configuration-specific manufacturer drawings below; dimension units and terminal orientation must match the selected mounting. |
Frame and trip unit together form the complete breaker. The frame code shown by the selector does not include the separately selected trip unit, rating plug, control-power accessories or final assembly bill of materials. ASD non-automatic switches shown in the shared catalogue are separate products. Breaking-class letters identify voltage-dependent ratings; do not interpret the largest kA figure as valid at every voltage.
Typical applications
- Main and feeder protection in low-voltage switchgear.
- Power distribution for data centres, industrial plants, healthcare facilities and standby-power assemblies, subject to the complete system design.
Specify your enquiry
For a focused quotation, include:
- Frame current, poles, F/D mounting, H/V terminal orientation and breaking class.
- Actual system voltage, frequency and prospective short-circuit current.
- LI/LSI/LSIG trip unit, rating plug, control supply, accessories and complete assembly requirements.
Download NOARK A25 catalogue (PDF)







