MCCB Breaking Capacity Selection
Engineering Intent
MCCB breaking capacity must be higher than the available short-circuit current at the installation point. The ZYM1 family in the low-voltage knowledge base covers standard, higher-breaking and high-breaking configurations up to 100kA by specification.
This article is written for engineers, EPC buyers and procurement teams who need to turn MCCB breaking capacity into a clear technical request instead of a vague product inquiry.
Key Selection Data
| Item | Data to Confirm |
|---|---|
| Check 1 | Available fault current |
| Check 2 | Icu and Ics requirement |
| Check 3 | System voltage AC400V or project-defined LV voltage |
| Check 4 | Feeder duty, selectivity and 2P/3P/4P pole requirement |
Standards and Evidence to Request
- IEC 60947-2 MCCB requirements
- GB/T 14048.2
- Panel short-circuit study
- Manufacturer breaker datasheet
For project approval, request a technical datasheet, outline drawing, wiring or terminal diagram where applicable, routine test report and nameplate information before shipment.
Common Specification Mistakes
- Selecting MCCB by ampere rating only
- Ignoring Ics service breaking capacity
- No selectivity review
- No distinction between thermal-magnetic ZYM1 and electronic ZYM1E trip units
RFQ Checklist
- State voltage and current
- Confirm fault level
- List Icu or Ics requirement
- Specify thermal-magnetic, electronic or leakage protection trip unit
Related Product Paths
Ziyao Power can review the single-line diagram, load schedule, panel drawing or tender sheet and convert the requirement into a practical quotation package.
Download This Guide as PDF
Save this technical guide for offline reference. Includes all tables, specifications, and contact information.
Related Articles
Low Voltage Switchgear Feeder Schedule Guide
A clear feeder schedule is the fastest way to obtain an accurate LV switchgear quotation and avoid breaker or panel changes later.
GCS vs MNS vs GGD Low Voltage Switchgear
GCS, MNS and GGD panels serve different installation and maintenance requirements, so the model should match project operation needs.
ACB vs MCCB Selection for LV Panels
ACBs are common for high-current incoming feeders while MCCBs are common for outgoing distribution feeders. ZY POWER low-voltage documentation maps this selection to ZYW1 intelligent ACB and ZYM1 / ZYM1E / ZYM1L MCCB families.