Dongfa Intelligent is a manufacturer of the Molded Case Circuit Breaker with Residual Current Protection. The GNM1L Series combines molded case circuit breaker protection with residual current protection in one device. It is available in 3-pole and 4-pole configurations, with rated current from 16A to 800A. Different frame sizes provide different residual operating current settings, breaking capacities, and operating life specifications for low-voltage distribution applications.
The residual current setting can be selected according to the normal leakage level and protection requirements of the circuit. Available IΔn settings vary by frame size:
Selected models provide time-delay settings of 0.5s, 0.9s, and 2.15s for systems requiring coordination between upstream and downstream residual current protection. Non-delay protection is available where faster interruption of residual current faults is required.
Frame sizes from 125A to 800A cover different distribution current requirements. At 400V, the available Icu reaches 65kA depending on the model and breaking capacity level, allowing the breaker to be matched to the prospective short-circuit current of the installation.
The main specifications of the Molded Case Circuit Breaker with Residual Current Protection are shown below. Actual configuration should be selected according to frame size, rated current, residual current setting, and required breaking capacity.
| Parameter | GNM1L-125 | GNM1L-250 | GNM1L-400 | GNM1L-600/800 |
| Maximum Frame Current | 125A | 250A | 400A | 600/800A |
| Rated Current In | 16-125A | 100-250A | 225-400A | 400-800A |
| Poles | 3/4 | 3/4 | 3/4 | 3/4 |
| Rated Insulation Voltage Ui | AC800V | AC800V | AC800V | AC800V |
| Rated Operating Voltage Ue | AC800V | AC800V | AC800V | AC800V |
| Rated Impulse Withstand Voltage Uimp | 8kV | 8kV | 8kV | 8kV |
| Breaking Capacity Level | L/M | L/M/H | L/M | L/M |
| Icu at 400V | 35/50kA | 25/35/50kA | 50/65kA | 50/65kA |
| Ics at 400V | 22/35kA | 18/22/35kA | 35/42kA | 35/42kA |
| Rated Residual Operating Current | 30/100/500mA | 100/300/500mA | 100/300/500mA | 300/500/1000mA |
| Rated Residual Non-Operating Current | 1/2 IΔn | 1/2 IΔn | 1/2 IΔn | 1/n IΔn |
| Electrical Life | 10000 operations | 10000 operations | 8000 operations | 8000 operations |
| Mechanical Life, Maintenance-Free | 20000 operations | 20000 operations | 10000 operations | 10000 operations |
| Mechanical Life, With Maintenance | 40000 operations | 40000 operations | 20000 operations | 20000 operations |
| Four-Pole Total Power Loss | 15.6W | 32W | 48W | 96W at 630A / 100W at 800A |
| Residual Current | Non-Delay Max Break Time | Time-Delay Max Break Time | Time-Delay Limiting Non-Driving Time |
| IΔn | 0.2s | 0.5 / 0.9 / 2.15s | — |
| 2IΔn | 0.15s | 0.4 / 0.8 / 1.9s | 0.2 / 0.4 / 1.0s |
| 5IΔn | 0.04s | 0.3 / 0.5 / 1.2s | — |
| 5 / 10IΔn | 0.04s | 0.3 / 0.5 / 1.2s | — |
The rated residual non-operating current is 1/2IΔn. For example, when the rated residual operating current is set to 100mA, the corresponding rated residual non-operating current is 50mA.
For the 250A frame, the ambient temperature correction factors are 1.00 at +40°C, 0.96 at +45°C, 0.91 at +50°C, 0.87 at +55°C, and 0.82 at +60°C.
For installation at 2000m, 3000m, 4000m, and 5000m, the corresponding working current correction factors are 1.00, 0.94, 0.88, and 0.83.
| Rated Current | Recommended Copper Busbar |
| 500A | 2×150mm² |
| 630A | 2×185mm² |
| 800A | 2×240mm² |
For high-current distribution cabinets, the four-pole total power loss of the breaker should also be included in the cabinet temperature-rise and ventilation assessment.
For replacement applications, provide the original breaker model, mounting dimensions, frame size, rated current, residual operating current, delay requirement, breaking capacity, and required quantity. Dongfa Intelligent can review these details before production to confirm the required product configuration and mounting compatibility.
Our product range includes high-voltage vacuum circuit breakers, vacuum load switches, high-voltage disconnect switches, electromagnetic coils, and low-voltage protection products such as the Molded Case Circuit Breaker with Residual Current Protection. High-voltage products cover 12kV, 24kV, and 40.5kV applications, while low-voltage products are designed for circuit protection in distribution systems.
Dongfa Intelligent operates a factory covering more than 2,000 square meters, with 2 production lines and 17 employees, including 4 R&D and technical personnel. The company is certified to ISO 9001, ISO 14001, and ISO 45001 management systems. Relevant products are manufactured and tested according to applicable GB and IEC standards, with relevant high-voltage products having undergone type testing by national-level testing institutions.
Dongfa Intelligent supports OEM/ODM and non-standard customization based on customer drawings, technical specifications, installation requirements, and product configurations. Technical documents, product test reports, and customized configurations can be provided according to project requirements.
The Molded Case Circuit Breaker with Residual Current Protection should be selected according to the normal leakage current of the circuit and the required protection level. The selected setting should provide sufficient margin above the normal leakage level while maintaining the required residual current protection. Cable length, cable type, connected loads, and operating conditions should also be reviewed.
Non-delay protection is used for circuits requiring faster interruption of residual current faults, while time-delay protection is used where upstream and downstream residual current protection coordination is required. Depending on the model, available delay settings include 0.5s, 0.9s, and 2.15s.
The recommended specifications are 2×150mm² for 500A, 2×185mm² for 630A, and 2×240mm² for 800A. The final specification should be confirmed according to the distribution cabinet structure, connection arrangement, and operating conditions.
The four-pole total power loss of the 800A frame is 100W. This value should be considered together with other heat-generating components when evaluating cabinet temperature rise and ventilation.
Yes. For replacement projects, provide the original breaker model, mounting dimensions, frame size, rated current, residual operating current, delay requirement, and breaking capacity. These details can be reviewed to confirm the required configuration and mounting compatibility.
Yes. Relevant product test reports and technical documents can be provided according to the product model and project requirements. The available documentation can be confirmed during product selection or quotation.
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No. 281, Wei 18th Road, Yueqing Economic Development Zone, Yueqing, Wenzhou, Zhejiang, China
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