Name: GYM9H-125 10kA High Breaking Miniature Circuit Breaker | GEYA Electric
SKU: GYM9H-125 10kA

Description

GYM9H-125 125A 10kA High Breaking Capacity MCB — Overview

The GYM9H-125 Miniature Circuit Breaker is a 10 kA high-breaking-capacity AC MCB designed for 50/60 Hz circuits at 240/415 V with rated currents up to 125 A, providing reliable overload and short-circuit protection for industrial mains, commercial sub-distribution, high-rise risers, and large residential boards. Compliant with IEC/EN 60947-2 and GB/T 14048.2, it extends the proven GYM9 platform into the heavy-current frame where standard 63 A MCBs can no longer be used.

Why the 125 A frame matters: A typical 6–63 A MCB cannot serve as an incoming main for a sub-board feeding several final circuits, nor can it carry the continuous current of large HVAC compressors, industrial machinery, EV charging hubs, or commercial kitchen lines. The GYM9H-125 closes that gap with up to 125 A continuous current and 10 kA breaking capacity in a compact 18 mm-per-pole DIN-rail body.

Key Features

■ 10 kA Breaking Capacity Robust arc-chute and current-limiting contacts safely interrupt high fault currents typical of industrial distribution.	■ Up to 125 A Continuous Heavy-duty bimetal + magnetic trip block designed for thermal stability at full load.
■ Dual Busbar Wiring Accepts both pin/fork comb busbars and cables up to 50 mm² — fast assembly in panels.	■ Contact Position Indicator Mechanical window shows true contact state — important for lock-out / safe isolation.
■ B / C / D Curves One frame fits resistive, mixed, and motor / transformer inrush loads.	■ Compact 18 mm/Pole DIN-rail (TH35-7.5) mounting — same modular width as standard 63 A MCBs.

Where the GYM9H-125 Outperforms the 6–63 A Range

The standard GYM9 (6 kA, 1–63 A) and GYM9H (10 kA, 1–63 A) are perfect for final circuits — lighting, sockets, small motors. The GYM9H-125 is engineered for the upper layer of the distribution tree:

Sub-board incomer / isolator — protecting a distribution panel that internally hosts dozens of 10–63 A final breakers.
Large HVAC / chiller / compressor feeders — where starting currents and continuous load exceed the 63 A frame.
EV-charging clusters — multiple 22 kW chargers behind one feeder require 80–125 A protection with high Icu.
Industrial machinery and welding lines — D-curve 125 A for high inrush.
Commercial kitchens, laundries, datacenter PDUs — sustained high-current loads.
Building risers / generator changeover panels — main-MCB duty up to 125 A.

GYM9 Family Comparison

Model	Breaking Capacity	Rated Current Range	Poles	Curves	Typical Use	Link
GYM9	6 kA	1 – 63 A	1P / 2P / 3P / 4P	B, C, D	Residential final circuits	View GYM9 in Catalog→
GYM9H	10 kA	1 – 63 A	1P / 2P / 3P / 4P	B, C, D	Commercial / light-industrial final circuits	View GYM9H-10kA →
GYM9H-125	10 kA	63 80 100 125 A	1P / 2P / 3P / 4P	B, C, D	Main incomer, large feeders, industrial loads	–

Standards & Compliance

Manufactured and tested to IEC/EN 60947-2 and GB/T 14048.2. CE marked, RoHS 2.0 compliant. Designed for global markets — EU, UK, Middle East, Southeast Asia, Africa, Latin America and OEM/ODM projects.

Where to Install the GYM9H-125

Thanks to the 125 A continuous rating and 10 kA short-circuit interrupting capability, the GYM9H-125 is suited to applications that exceed the 63 A frame of the standard GYM9 / GYM9H series:

Industrial Distribution
Factory mains, machine feeders, welding lines, compressors.

Commercial Buildings
Sub-board incomer, HVAC feeders, lift / pump panels.

High-Rise & Residential
Riser distribution boards, apartment incomers, large villas.

EV Charging
Feeder protection for AC charger clusters (22 kW × n).

Data Centers
PDU upstream protection, UPS bypass, generator switchover.

Renewables
AC-side protection for inverters in PV / storage plants.

Technical Specifications

Parameter	Specification
Product Model	GYM9H-125
Rated Current (In)	63, 80, 100, 125 A
Rated Voltage (Ue)	240/415 V~ ; 230/400 V
Rated Insulation Voltage (Ui)	500 V
Rated Impulse Withstand Voltage (Uimp)	4 kV
Working Frequency	50 / 60 Hz
Breaking Capacity (Icu)	10,000 A (10 kA)
Number of Poles	1P / 2P / 3P / 4P
Tripping Curves	B, C, D
Mechanical Life	20,000 operations
Electrical Life	10,000 operations
Wiring Capacity	6 – 50 mm²
Standards	IEC/EN 60947-2, GB/T 14048.2
Certifications	CE, RoHS 2.0
Mounting	35 mm DIN rail (TH35-7.5)

Performance Characteristics (Tripping Test)

Curves	Test Current	Initial State	Time (30 °C)	Result
B, C, D	1.13 In	Cold	t ≥ 1 h (In ≤ 63) ; t ≥ 2 h (63 < In ≤ 125)	No tripping
	1.45 In	Thermal	t < 1 h (In ≤ 63) ; t < 2 h (63 < In ≤ 125)	Trip
	2.55 In	Cold	1 s < t < 120 s	Trip

Temperature Compensation (Current Correction Factor)

Ambient Temp.	-20 °C	-10 °C	0 °C	10 °C	20 °C	30 °C	40 °C	50 °C	60 °C
Correction Factor	1.25	1.20	1.15	1.10	1.05	1.00	0.95	0.90	0.85

Outline & Installation Dimensions (mm)

Pole	Width (W)	Height	Depth
1P	18 mm	89.5 mm	80 mm
2P	36 mm	89.5 mm	80 mm
3P	54 mm	89.5 mm	80 mm
4P	72 mm	89.5 mm	80 mm

Frequently Asked Questions

Q1. What is the GYM9H-125?

The GYM9H-125 is a high-breaking-capacity AC miniature circuit breaker (MCB) rated up to 125 A with a 10 kA short-circuit breaking capacity, designed for 50/60 Hz networks at 240/415 V.[[1]](https://www.geya.net/product/gym9h-125-10ka-high-breaking-miniature-circuit-breaker/) Within the GYM9 family, the “H” suffix denotes the high-breaking-capacity variant and the “-125” extends the platform from the standard 1–63 A frame up into the 63 / 80 / 100 / 125 A heavy-current frame — closing the gap between final-circuit MCBs and small MCCBs. It is available in 1P / 2P / 3P / 4P configurations on a 35 mm DIN rail at 18 mm per pole, and is built to IEC/EN 60947-2 and GB/T 14048.2.

Q2. What functions does it provide?

Overload protection — thermal-bimetal inverse-time element trips on sustained overcurrent, sized for continuous duty up to 125 A.
Short-circuit protection — instantaneous electromagnetic trip per B / C / D curve, interrupting fault currents up to 10 kA.
Circuit isolation — full positive disconnection for safe maintenance of large feeders and sub-boards.
Manual switching — suitable for infrequent on/off operations of high-current circuits.
Status indication — mechanical contact-position indicator window for verified isolation.
Dual busbar wiring — accepts both comb-busbar pins/forks and cables up to 50 mm² for fast panel assembly.

Q3. Which key parameters drive model selection?

Rated current (In) — match to continuous load current (63, 80, 100 or 125 A), adjusted by the temperature-compensation factor.
Number of poles — 1P for single-phase line, 2P for L+N, 3P for three-phase, 4P for 3P+N systems.
Rated voltage (Ue) — confirm the system voltage is within the 240/415 V~ ; 230/400 V range.
Prospective short-circuit current — must be lower than the 10 kA breaking capacity at the point of installation; for higher Isc, cascade with an upstream MCCB.
Tripping curve (B / C / D) — match to load inrush characteristics (B: resistive / cables; C: mixed loads; D: motors, transformers, welding).
Ambient temperature — apply the correction factor (1.25 at -20 °C → 0.85 at 60 °C).
Wiring capacity — confirm cable cross-section is within 6 – 50 mm² and torqued correctly.

Q4. What configuration options are currently available?

Poles: 1P, 2P, 3P, 4P
Rated current: 63, 80, 100, 125 A
Tripping curves: B, C, D
Breaking capacity: 10 kA — for lower-current circuits (1–63 A) consider the GYM9H (10 kA, 1–63 A) or the basic GYM9 (6 kA, 1–63 A)
Accessories: auxiliary contact (AX), alarm contact (AL), shunt trip (MX), under-voltage release (MN), motorized / remote operating mechanism

Q5. Which standards does it meet, and which markets is it designed for?

GEYA GYM9H-125 is designed and tested to IEC/EN 60947-2 and GB/T 14048.2, is RoHS 2.0 compliant, and carries CE certification. It targets:

European, Asia-Pacific, Middle East, African and Latin-American markets that specify IEC/EN-compliant high-current MCBs;
Industrial and commercial panel builders needing a 125 A main-incomer or large-feeder breaker with 10 kA Icu;
High-rise residential, EV-charging, data-center and renewable-energy projects where the standard 63 A frame is insufficient;
Cost-sensitive projects needing a certified 125 A / 10 kA MCB that performs on par with tier-1 brands at a far more economical price point.

Q6. What installation precautions should I follow?

Mounting: Install vertically on a 35 mm DIN rail (TH35-7.5) inside a dry, dust-protected enclosure. The breaker itself is IP20 — the enclosure must provide the final ingress protection.
Wiring direction: Connect the supply to the top terminals; observe phase / N markings on multi-pole versions.
Spacing & ventilation: Provide adequate clearance between adjacent high-current breakers and heat sources; at this current rating, mutual heating must be controlled — apply the temperature-compensation factor when ambient exceeds 30 °C (×0.90 at 50 °C, ×0.85 at 60 °C).
Tightening torque: Tighten terminal screws to approx. 2.0 N·m using a wire size within 6 – 50 mm². Re-check torque after the first thermal cycle. No bare wire whiskers outside the terminal.
Fault-level verification: Confirm the prospective short-circuit current at the installation point is ≤ 10 kA. If higher, cascade with an upstream MCCB.
Pre-energizing check: Verify continuity, insulation resistance and correct ON/OFF indication via the contact-position window before commissioning.
Periodic maintenance: Operate the breaker manually from time to time to confirm mechanical operation; replace if it has interrupted a fault close to its 10 kA rating.
Do not exceed ratings: Never apply DC voltage to this AC MCB — use the dedicated DC MCB version for PV / battery circuits.

GYM9H-125-10kA High Breaking Miniature Circuit Breaker