Rated Operational Voltage:
Main bus: Usually 400V AC (50Hz system, line voltage) or 480V AC (60Hz system). This is the standard voltage level for low-voltage power distribution.
Outgoing line circuit: The same voltage as the main bus (400V/480V). Some circuits may also provide single-phase 220V (phase voltage).
Rated Insulation Voltage:
Usually 690V AC or 1000V AC. It indicates the highest voltage to the ground or between phases that the electrical components and busbars in the cabinet can withstand (power frequency withstand voltage), which is a reflection of the safety margin.
Rated Frequency:
50Hz or 60Hz.
Rated Current of Main Busbar:
This is the upper limit of the total current that the cabinet can carry. Common ranges are wide: 250A, 400A, 630A, 800A, 1000A, 1250A, 1600A, 2000A, 2500A, 3150A, etc. The selection is based on the upstream transformer capacity and the total downstream load calculation current.
Rated Current of Feeder Circuits:
Refers to the rated current of each output branch switch. The range is very large, from 16A, 32A, 63A to 100A, 160A, 250A, 400A, 630A or even higher (depending on the cabinet type and main switch).
Calculate and select according to the connected load (motor power, heater power, etc.).
Rated Short-time Withstand Current (Icw - Rated Short-time Withstand Current):
Indicates the maximum effective value of short-circuit current that the main busbar can withstand for a certain period of time (usually 1 second) without permanent deformation. For example: 15kA, 25kA, 35kA, 50kA, 65kA, 100kA. This is a key parameter for measuring the dynamic stability of the cabinet and needs to be selected according to the expected short-circuit current at the installation point.
Rated Peak Withstand Current (Ipk - Rated Peak Withstand Current):
Indicates the maximum short-circuit current peak value (first half-wave peak value) that the main busbar can withstand. Usually associated with Icw, it is about 2.2 times of Icw (coefficient n). It is also an indicator of dynamic stability.
Number of Feeder Circuits:
The number of feeder switches (molded case circuit breakers MCCB or fuse switches) installed in the cabinet. From a few to dozens, depending on the size of the cabinet and the size of the switch.
Ingress Protection (IP Rating):
The protection level of the cabinet against external solid foreign objects and water intrusion. Common:
IP30: Protected against solid foreign objects larger than 2.5mm, not waterproof (standard for indoor distribution rooms).
IP41/IP42: Protected against solid foreign objects larger than 1mm, vertical dripping/tilted 15° dripping (commonly used in workshop environments).
IP54: Dustproof and splashproof (dust, humid environment).
IP65: Dust-tight, water-proof (outdoor or harsh industrial environment).
Main Incoming Switch Type:
Frame Circuit Breaker (ACB): Used for large current incoming lines (above 630A), with high breaking capacity and strong protection functions (adjustable long delay, short delay, instantaneous, ground fault protection).
Molded Case Circuit Breaker (MCCB): Used for medium current incoming lines (usually below 630A), compact structure.
Isolating Switch/Disconnector: Only provides isolation function (with obvious disconnection point), no protection function, usually needs to be used with lower-level protection switches or fuses. Some have simple short-circuit protection (fuse-type isolating switches).
Feeder Switch Type:
Molded Case Circuit Breaker (MCCB): Most commonly used, provides overload and short-circuit protection, adjustable.
Fuse Switch Disconnector: A combination of switch + fuse. The fuse provides short-circuit protection (high breaking capacity), and the switch provides isolation and overload protection (usually limited). The cost may be lower.
Contactor + thermal relay / motor protector: If the circuit requires remote start and stop control (such as motor), a contactor (to perform start and stop) and a thermal relay / electronic motor protector (to provide overload, phase loss, etc. protection) will be added after the circuit breaker / fuse switch. But strictly speaking, circuits with control functions are usually classified as motor control center (MCC) cabinets. Pure power cabinets mainly focus on power distribution and protection.
Cabinet Dimensions:
Height: Common 1800mm, 2000mm, 2200mm.
Width: Common 600mm, 800mm, 1000mm, 1200mm.
Depth: Common 600mm, 800mm, 1000mm.

Power Distribution: The most basic function is to distribute the power from the transformer or low-voltage main distribution cabinet to multiple outgoing circuits through the busbar to supply dispersed power loads.
Overload Protection: Through the circuit breaker (MCCB) or thermal relay/motor protector of the outgoing circuit, prevent the load current from exceeding the allowable value of the wire or equipment for a long time and causing overheating damage.
Short-circuit Protection: Through the circuit breaker (MCCB) or fuse of the outgoing circuit, the fault current is quickly cut off when a phase-to-phase or phase-to-ground short circuit occurs, protecting the line and equipment from huge electric power and thermal effects.
Isolation Function: The main incoming switch and each outgoing switch provide safe electrical isolation points (obvious disconnection points) to ensure that the equipment is safely isolated from the power supply during inspection and maintenance.
Metering & Monitoring - optional but common:
Voltmeter, ammeter: monitor the main bus voltage and the current of each outgoing line circuit (usually need to be equipped with current transformer CT).
Multi-function power meter: monitor voltage, current, power (active, reactive, apparent), power factor, electric energy, frequency, harmonics, etc., usually installed on the incoming line side.
Structural Characteristics:
Bus system: usually copper or aluminum busbars are used, and the surface is tinned or silver-plated to reduce contact resistance and oxidation resistance.
Installation method:
Fixed type: All electrical components are fixedly installed, and wiring is also completed in the cabinet. Low cost, power off is required for maintenance.
Drawer type: The outgoing line circuit is installed in a removable drawer unit. The main circuit and auxiliary circuit are connected through plug-ins. Advantages: quick and convenient maintenance/replacement (part of the circuit can be withdrawn with power), high isolation safety. Disadvantages: high cost, slightly complex structure. Commonly used in situations requiring high reliability and fast maintenance.
Cabinet material: high-quality cold-rolled steel plate (SPCC), surface spray treatment (anti-corrosion, beautiful).
Ventilation and heat dissipation: cabinet top fan, cabinet side/door panel ventilation mesh (protection level needs to be considered).
Expandability: The possibility of adding circuits in the future is usually considered during design (reserved space or busbar expansion capacity).
Safety & Compliance:
Comply with relevant safety standards and specifications (such as IEC 61439-1/2, GB 7251.1/12 low-voltage complete switchgear and control equipment standards).
Reliable grounding system (PE bar).
Sufficient electrical clearance and creepage distance.
Door panel with lock to prevent unauthorized operation.
The protection level meets the requirements of the installation environment.