Power distribution cabinets
- Incoming: breaker / disconnect main incoming, busbar cross-section calculated against short-circuit capacity and current-carrying capacity
- Feeders: separate circuits for motors, lighting, receptacles and heating, each with its own breaker and protection
- Busbars: TMY tinned copper busbars torqued to 30–40 N·m, with match marks at joints for re-checking
- Components: Schneider / ABB / Siemens / Chint, or specified on the drawing, or customer-supplied and shipped to our plant
- Testing: insulation resistance, dielectric withstand, circuit continuity and powered functional test on every unit
Specifications
The table below covers 80% of factory distribution room cases. Anything outside it we can still build — those are engineered items, quoted separately, with an indicative price the same day.
| Type | Floor-standing power distribution cabinet, single-door / double-door / split upper-lower door, can be paralleled with adjacent cabinets |
|---|---|
| Standard sizes (W×D×H) | 600×600×1800 / 800×600×1800 / 800×600×2000 / 1000×600×2000 mm, custom build available |
| Enclosure construction | 2.0 mm cold-rolled carbon steel, seam-welded with reinforcing ribs, electrostatic powder coating |
| Surface treatment | Degrease → derust → phosphating → electrostatic powder coating 60-80 μm, baked at 200 °C for 30 minutes |
| IP rating | IP54 standard / IP65 optional (GB 4208 / IEC 60529) |
| Busbar system | TMY tinned copper busbars, torqued to 30–40 N·m, with match marks at joints |
| Cable entry | Top / bottom cable entry with gland plate or cable tray cutouts; feeder circuits numbered per drawing |
| Door and lock | Multi-point door locks, optional viewing window; split upper-lower door layout (main switch above, feeders below) |
| Rated voltage | AC 380V / 400V, 50 Hz, three-phase (with neutral / ground) |
|---|---|
| Busbar current-carrying capacity | Main busbar ≤2000 A; branch busbar cross-section sized per circuit ampacity |
| Incoming line method | Breaker incoming / disconnect switch incoming / dual-source incoming (ATS), selected per the power supply scheme |
| Outgoing circuits | Motor, lighting, receptacle, heating, control and other circuits fed out as separate branches, each with its own breaker protection |
| Protection configuration | Overload, short circuit, ground fault (selected per circuit characteristics); motor circuits use thermal-magnetic or electronic trip units |
| Grounding systems | PE grounding busbar laid out separately; grounding continuity tested circuit by circuit |
| Metering (optional) | Built-in meter or power meter for branch / main metering |
| Component brands | Schneider / ABB / Siemens / Chint, or as specified on the drawing, or customer-supplied and shipped to our plant |
| Main incoming + multiple outgoing feeders | One main incoming line with several outgoing feeders supplying different equipment — the most common form of power distribution cabinet |
|---|---|
| Dual Power Source Incoming Lines | Utility power + backup dual-source incoming with automatic ATS transfer, keeping critical equipment online |
| Metering + outgoing feeders | Main incoming with metering; outgoing feeders supply separate branches, suited to metering by area or floor |
| Centralized motor feed | Multiple motor circuits grouped in one cabinet with thermal-magnetic protection, controlled locally or remotely |
| Bus tie coordination | Two busbar sections linked through a bus tie breaker, so one section can be serviced while the other stays energized |
| Outdoor power distribution cabinet | Rainproof outdoor power distribution cabinet, IP65, with a raised base and anti-condensation provision |
| Reference standards | GB/T 7251.1 / IEC 61439-1 (assemblies); GB/T 7251.12 (distribution boards) |
|---|---|
| Clearance & creepage | Meets pollution degree 3 and overvoltage category III requirements |
| Insulation resistance | ≥1 MΩ (500V megohmmeter) |
| Power frequency withstand voltage | Main circuit 2500V / 1 min, control circuit 1500V / 1 min |
| Grounding continuity | Grounding path from the PE busbar to every component tested point by point |
| Routine tests (every unit) | Circuit continuity, insulation resistance, dielectric withstand, grounding continuity, powered functional test, indication and interlocking |
| Documents with shipment | Electrical schematic, circuit list, BOM with brand and model, test report, factory photos |
Five steps to specify your run
A configuration summary is generated as you go. It travels with your inquiry, saving a round of confirmation.
Build details
Systems have been in service for decades, and the failure points are always the same few: poor busbar contact, water ingress at the door seal, high temperature rise in the correction cabinet, and mis-phased outgoing feeders. The six hard rules below are written for exactly these points — every cabinet can be traced to them.
Busbar torque tightening
Tin-plated copper busbars are tightened to 30–40 N·m and marked with a line at each joint. Under-torque causes heating; if the mark fades, you can still recheck for loosening.
Circuits split by load
Motor, lighting and heating circuits are fed on separate circuits and laid out separately. Loads of different types have different starting characteristics — combining them on one circuit only causes nuisance tripping.
Busbar cross-section calculation
Both main and branch busbars are sized by current-carrying capacity and short-circuit capacity. An undersized cross-section does not fail the same day — it is the slow temperature rise under high current that ages the insulation.
Upper and lower door zones
The main breaker is on top and the feeders below, in separate upper and lower door zones. Servicing a feeder circuit does not require touching the main breaker — a clear step up in safety.
Point-by-point PE testing
The grounding busbar is laid out independently, and the grounding circuit of every component is tested point by point before shipment. When protection operates, this grounding path must be reliable.
Energized functional test
Every unit undergoes an energized functional test before shipment — indicators, interlocks and protection operations are all checked. No batch sampling.
Photos & enclosure construction
Below are photos taken in our own shop — from the complete unit down to the internal busbars and secondary wiring. Every build detail can be checked item by item.
Image key: 01–05 are shop photos (the numbers match the shot list). The line drawing shows the front elevation of the enclosure; dimensions match the specification table above.
Where these cabinets go
These are the routine applications — we can talk scheme and configuration directly. For the industry view, see the industry pages.
Factory floor power distribution
Separate feeds for each production machine, motor and heating unit.
Pump stations and wastewater plants
Centralized feeds for pumps, fans, screens and similar equipment.
Commercial buildings and floors
Power distribution by floor or zone, with meters.
Mining and heavy machinery
Power feeds for crushing, conveying and hoisting equipment.
Municipal & Infrastructure
Power distribution for road lighting, pump stations and drainage pumping stations.
Outdoor Power Distribution
Weatherproof outdoor power cabinet for temporary or open-air equipment.
Commercial terms
Specification dated September 2026; quotations follow this.
| Drawings & design | Free |
| MOQ | 1 unit (5 or more recommended for production) |
| Production lead time | 15-25 days after drawing approval |
| on-time delivery | 98% |
| Warranty | 12 months |
| Loading port | Ningbo / Shanghai, China |
| Component brands | Schneider / ABB / Siemens / Chint |
| Factory visit & dispatch confirmation | Factory visits welcome; finished-cabinet photos and video before dispatch |
| Capacity | 5,800+ units / year |
Documents for your engineering team
Selection manual, outline dimensions and RFQ checklist — for the customer's electrical engineer. All three documents are being organized by product line; download links go live once complete.
Six questions procurement and electrical engineers ask most
What is the difference between a power distribution cabinet and a lighting distribution box?
A power cabinet handles power equipment — motors, pumps, fans and other high-current three-phase loads — with heavy busbars and few, large circuits. A lighting box handles end-of-line lighting and receptacles, with many small circuits and mostly modular components. In the distribution system the two sit in a parent-child relationship: the power cabinet upstream, the lighting box at the end.
How do I calculate outgoing circuits? How many ways should I quote?
Work from the equipment list: every piece of equipment that needs its own protection and control counts as one circuit. Send us the equipment list, ratings, and whether local or remote control is required, and we will lay out the circuit schedule and cabinet type for you.
Can we use our specified component brands?
Yes. Schneider, ABB, Siemens and Chint are standard configurations. Other brands can be specified per drawing, or you can supply components yourself and ship them to our plant — we inspect them on receipt and then assemble the cabinet.
Can you do dual-source incoming supply?
Yes. Utility plus backup dual-source incoming supply with ATS automatic transfer keeps critical equipment running. Transfer time depends on the nature of the loads, so tell us which loads need it when you inquire.
What if we need to add circuits later?
We recommend reserving about 15% spare circuits and busbar margin when the cabinet is laid out. When the time comes, adding a circuit costs far less than replacing the cabinet.
What do I need to provide for a quote?
Supply scheme (incoming method, busbar capacity), equipment list and ratings, number of outgoing circuits, whether metering or dual-source is needed, installation environment and size constraints. A system diagram is ideal; if you don't have one, a circuit schedule is enough for us to produce a preliminary scheme.
Other cabinet types in the same main circuit
Related products use color-block placeholders for now (product photos not yet complete; they will be replaced together). Internal links will be filled in once live URLs are confirmed.
Have a distribution system diagram? Send it straight over and we'll lay out the cabinet
Send us your supply scheme and equipment list for a free circuit schedule and cabinet layout · Quote within 24 hours. Direct from the source factory, MOQ 1 unit, 15–25 day delivery, 1-year warranty.
ISO 9001:2015 · CE(LVD+EMC) · CQC · IP65
When you write, include: single-line diagram or primary scheme, switch room layout, load list, and component brand requirements. You do not need complete drawings — capacity and cabinet type are enough to start.