Power Distribution Cabinet

Power Distribution Cabinets (Low Voltage 400V - 690V) | Custom Manufacturer

Our low-voltage power distribution cabinets deliver structured electrical power allocation, motor control, and circuit protection for industrial facilities, commercial buildings, and infrastructure projects. Manufactured in compliance with IEC 61439-1/2 standards, these floor-standing and wall-mounting enclosures cover rated currents from 100A up to 6300A with short-time withstand currents up to 100kA/1s.

Manufacturing Capacity
• Production Footprint: 28,000 m2 enclosure fabrication and electrical assembly shop equipped with CNC punching, laser cutting, automated polyurethane foam gasket dispensing, and busbar processing machinery.

• Assembly Output: 350+ fully wired low-voltage switchboard and distribution panels monthly.

• Quality Verification: 100% dielectric voltage withstand testing, primary current injection, and automated wire point-to-point continuity checks prior to packing.

Product Categories

Category	Rated Current	Operational Voltage	Form of Separation	Structure Type	Primary Application
Main Distribution Board (MDB)	1250A - 6300A	400V / 690V	Form 3b / Form 4a / Form 4b	Floor-standing modular frame	Main substation low-voltage side, large industrial plants, data centers
Sub-Distribution Board (SDB)	250A - 1250A	400V	Form 2b / Form 3a	Floor-standing or wall-mounting	Building floor power distribution, workshop sections, commercial hubs
Motor Control Center (MCC)	400A - 2500A	400V / 690V	Form 3b / Form 4b	Fixed / Withdrawable (Draw-out) buckets	Heavy industry, water treatment plants, process automation lines
Outdoor Feeder Pillar / Kiosk	100A - 800A	400V	Form 1 / Form 2	Double-door weather-proof cabinet	Utility networks, street lighting, outdoor solar inverter AC collection

Product Selection by Application

Industrial Plants & Process Facilities
Configured with Form 3b or Form 4b internal separation to isolate busbars, functional units, and external terminals, preventing fault propagation.

High short-circuit withstand capacity up to 100kA/1s matching heavy transformer outputs.

Incorporates withdrawable Motor Control Center (MCC) units allowing live replacement of motor starter buckets without shutting down main busbars.

Commercial Buildings & Data Centers
Compact footprint layout matching strict electrical room dimensional limits.

Integrated automatic power factor correction (APFC) capacitor banks and harmonic filter panels.

Pre-wired smart metering units supporting Modbus RTU and Ethernet communication protocols for Building Management Systems (BMS).

Renewable Energy & Outdoor Environments
IP55 to IP65 protection ratings utilizing CNC polyurethane foam gaskets and rain hoods.

C4/C5 anti-corrosion exterior powder coating applied over zinc-coated or galvanized steel substrates.

Bi-directional power handling options with integrated automatic transfer switches (ATS) for dual-grid or generator supply.

Key Specifications

Parameter	Main Distribution Board (MDB)	Motor Control Center (MCC)
Rated Operational Voltage (Ue)	Up to 690V AC	Up to 690V AC
Rated Insulation Voltage (Ui)	1000V AC	1000V AC
Rated Main Busbar Current (In)	1250A / 1600A / 2500A / 4000A / 6300A	630A / 1250A / 2000A / 2500A
Short-Time Withstand Current (Icw)	50 kA / 65 kA / 85 kA / 100 kA (1s)	35 kA / 50 kA / 65 kA (1s)
Form of Internal Separation	Form 2b, Form 3b, Form 4a, Form 4b	Form 3b, Form 4b
Enclosure Protection Rating (IP)	IP30 / IP42 / IP54 (Custom IP65 available)	IP42 / IP54
Mechanical Impact Rating	IK09 / IK10	IK09 / IK10
Busbar Coating	Silver-plated or tin-plated contact zones	Silver-plated contact zones
Operating Temperature Range	-10 deg C to +40 deg C (Extendable to +55 deg C)	-10 deg C to +40 deg C
Standard Compliance	IEC 61439-1 & 2, BS EN 61439	IEC 61439-1 & 2, UL 891 (Option)

Configuration & Component Options

Circuit Breakers & Switchgear
• Air Circuit Breakers (ACB): 3-pole / 4-pole draw-out types up to 6300A with electronic trip units (LSIG protection).

• Molded Case Circuit Breakers (MCCB): Fixed or plug-in types with thermal-magnetic or electronic trip mechanisms.

• Component Sourcing: Assemblies incorporate tested local brands or client-specified international components (e.g., Schneider Electric, ABB, Siemens, Eaton).

Busbars & Structural Conductor System
• Busbar Material: T2 grade high-conductivity electrolytic copper (purity > 99.9%).

• Surface Treatment: Full tin plating or localized silver plating at joint locations to lower contact resistance.

• Color Identification: Phase bands (L1, L2, L3, N, PE) marked using heat-shrinkable insulation tubing across all bus run routes.

Secondary Control & Monitoring
• Digital Power Meters: Multi-function energy meters displaying V, A, kW, kWh, power factor, and THD.

• Internal Climate Control: Thermostat-controlled ventilation fans, anti-condensation space heaters, and louvers with dust filters.

• Terminal Blocks: DIN-rail mounted flame-retardant terminal strips with permanent laser-printed wire tags.

Standards & Testing

IEC 61439-1: Low-voltage switchgear and controlgear assemblies - General rules.

IEC 61439-2: Power switchgear and controlgear assemblies.

IEC 60529: Degrees of protection provided by enclosures (IP Code).

IEC 62262: Degrees of protection provided by enclosures for electrical equipment against external mechanical impacts (IK Code).

Type Test & Verification Documentation
Standard panel designs match IEC 61439 verification requirements. Test certificates from third-party accredited laboratories (such as DEKRA, TUV, or CNAS) are submitted during technical approval:
Short-circuit withstand strength verification on main busbar systems.
Temperature-rise limits testing at rated currents.
Clearance and creepage distance checks.
Dielectric property verification.

Factory Acceptance Testing (FAT)
Every completed cabinet undergoes full routine inspection before shipment:
Insulation resistance and high-voltage dielectric withstand test (2.5kV AC for 1 minute).
Primary and secondary circuit continuity check against approved wiring schematics.
Mechanical operation checks on all breaker racking mechanisms, door locks, and safety interlocks.
Torque verification on all structural bolts and electrical busbar connections.
IP sealing and paint thickness inspection.

Customization Process

We build every power distribution cabinet to match project-specific Single Line Diagrams (SLDs), layout dimensions, and cable entry configurations.

Step 1

SLD & Bill of Materials (BOM) Review

Step 2

3D Enclosure Layout & Busbar Thermal Calculations

Step 3

Engineering Drawing Submission (GA, Schematic, Terminal Layouts)

Step 4

CNC Sheet Metal Punching, Bending & Electrostatic Powder Coating

Step 5

Busbar Bending, Plating & Enclosure Assembly

Step 6

Secondary Wiring & Component Installation

Step 7

Routine Factory Acceptance Testing (FAT)

Step 8

Vacuum Wrapping & Wooden Crate Packing

Manufacturing & Quality Control

Sheet Metal & Coating Integrity

Cabinet structures are fabricated using 1.5 mm to 2.5 mm cold-rolled steel or Al-Zn coated steel sheets on automated CNC punch presses to maintain dimensional accuracy within +/-0.2 mm.
A 7-stage chemical cleaning and phosphating pre-treatment process precedes electrostatic epoxy-polyester powder coating. Paint thickness is verified to exceed 80 um.

Electrical Assembly Precision

All busbar connections are tightened using torque-calibrated drivers according to ISO standard torque values and marked with tamper-evident inspection sealant.
Secondary wiring harnesses use color-coded flexible copper conductors with ferrule terminals at every termination point.

Applications

Industrial Facilities

Manufacturing plants, paper mills, chemical processing units, mining sites.

Commercial Buildings

Office towers, shopping malls, hotels, hospital infrastructure.

Public Infrastructure

Railway stations, airports, water treatment facilities, tunnel distribution systems.

Power & Energy

Solar PV AC combiner/distribution boxes, wind farm auxiliary power panels, thermal plant distribution centers.

Packaging & Delivery

Internal Protection

All breakers are locked in open/test positions. Desiccant packs are placed inside each column to prevent moisture condensation during sea freight.

Enclosure Sealing

Panels are individually wrapped in heavy-duty stretch film and corner-protected with high-density foam buffers.

Shipping Container

Packed in IPPC-certified fumigated plywood crates with reinforced solid wood bases. Crates feature bottom runner channels for forklift handling and top eye-bolts for crane hoisting.

Our Certificate

FAQ

Q: What information do you require to provide a formal quotation?

A: We require your Single Line Diagram (SLD), general arrangement (GA) space constraints, main breaker specifications, preferred component brands, IP rating, and Form of Separation requirement.

Q: Can we specify switchgear component brands (e.g., Schneider Electric, ABB, Siemens)?

A: Yes. We integrate client-specified brands for ACBs, MCCBs, contactors, relays, and meters into our enclosure frameworks based on your project schedule of quantities.

Q: How do you verify that the internal temperature rise remains within standard limits?

A: We calculate busbar cross-sectional areas based on current density limits (typically < 1.5A/mm2 for copper) and install forced ventilation fans or convection louvers according to thermal calculations matching IEC 61439 guidelines.

Q: What is the difference between Form 2, Form 3, and Form 4 internal separation?

A: Form 2 separates busbars from functional units. Form 3 separates busbars, functional units, and terminals from each other. Form 4 isolates individual functional units and their dedicated output terminals into separate compartments to maximize operational safety.

Q: Can your distribution cabinets accommodate top or bottom cable entry?

A: Yes. Top or bottom gland plates are removable and can be custom-punched or left blank with brass/aluminum gland plates to suit site cable entry configurations.

Q: What is your standard production lead time for custom switchboards?

A: Standard lead time is 4 to 6 weeks following engineering drawing sign-off (GA and schematics) and component availability confirmation.

Q: Do you provide type test certificates for the complete assembly?

A: Yes. Type test verification reports covering short-circuit withstand, temperature rise, and degree of protection (IP) according to IEC 61439 are available during the technical submittal phase.

Q: How do you protect cabinets installed in outdoor or high-corrosion environments?

A: For harsh environments, we manufacture enclosures using 304 or 316L stainless steel, or apply C4/C5 grade anti-corrosion powder coating, combined with seamless foam gasket seals to achieve IP65 protection.

We are one of the most reliable power distribution cabinet manufacturers and suppliers in China, specialized in providing high quality customized products. We warmly welcome you to buy bulk power distribution cabinet for sale here from our factory. Contact us for quotation.

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