SIEMIENS MCCB Series Short Circuit Rating Guide

QPH/BQH/BLH series: Enhanced low-voltage circuit breaker, current range 15-125A, pole count 1P/2P/3P, compatible with 240V/480V, with higher breaking capacity, suitable for medium-sized commercial and industrial scenarios.

ED4/ED6 series: Universal circuit breaker, covering 240V/480V, current range 15-125A, pole count 1P/2P/3P, strong compatibility, suitable for multi scene distribution.

FD6-A/FXD6-A series: High voltage dedicated circuit breaker, suitable for 480V/600V, current range 70-250A, pole count 2P/3P, designed for industrial high-voltage circuits.

MD6/MXD6 series: Large industrial circuit breaker, suitable for 480V/600V, current range 400-800A, pole count 2P/3P, used for main power distribution in large industrial plants.

4.1.2 Fuse series

J-type fuse: universal type, suitable for 240V/480V/600V, maximum current 600A, pole count 1P/2P/3P, suitable for various medium and low voltage scenarios.

R-type fuse: enhanced type, suitable for 240V/480V, maximum current 1200A, 2P/3P poles, high breaking capacity, suitable for industrial high-voltage circuits.

T-type fuse: High voltage dedicated type, suitable for 240V/480V/600V, maximum current 1200A, 2P/3P poles, excellent insulation performance, suitable for high-voltage industrial scenarios.

L-type fuse: extra large, suitable for 240V/480V, maximum current 6000A, 2P/3P poles, extremely strong breaking capacity, used for large industrial critical circuits.

4.2 Core parameters of branch circuit breakers

Pole numbers: 1P (single-phase circuit), 2P (single-phase/two-phase circuit), 3P (three-phase circuit), must be strictly matched with the main equipment and distribution system type.

Current range: 15-20A (small load), 15-30A (lighting/socket), 15-50A (small motor), 15-70A (medium load), 15-125A (large load), 200-400A (industrial equipment), 400-600A (main circuit), etc., depending on the load power selection.

Voltage adaptation: 120V (single-phase low voltage), 240V (single-phase medium voltage), 277V (three-phase lighting), 347V (high-voltage lighting), 480V (three-phase industrial), 600V (high-voltage industrial), which should be consistent with the system voltage.

Key application suggestions and precautions

6.1 Selection Core Suggestions

Voltage priority matching: First, clarify the voltage of the distribution system (240V/480V/600V), and then select the combination from the corresponding voltage section to avoid cross voltage selection.

Accurate current adaptation: Select the current range of the branch circuit breaker based on the actual load current, and ensure that the maximum current of the main equipment is greater than or equal to the maximum current of the branch equipment.

Scenario specific selection: QP/BQ/BL series+J-type fuses are preferred for civilian/small commercial use; FD6-A/FXD6-A series+T/L type fuses are preferred for high voltage in industry; Priority should be given to selecting the 100000A/200000A combination with higher certification levels for key facilities.

6.2 Installation and operation precautions

During installation, it is necessary to verify the model, number of poles, voltage, current, and other parameters of the main and branch equipment to ensure consistency with the document combination. Mixing unverified equipment is prohibited.

Regularly check the information on the equipment nameplate, confirm whether the rated value of the disconnection and the serial combination identification are clear, and replace the nameplate in a timely manner if there is wear and tear.

After a short circuit fault, it is necessary to check all devices in the series combination. If the main device triggers a disconnection, the status of the branch devices should be checked synchronously to ensure that there is no hidden damage.