Power distribution boxes
- Main breaker: molded case circuit breaker (MCCB) ≤400 A, optional residual current protection
- Motor circuits: breaker + contactor + thermal overload relay, local pushbutton start/stop
- Feeder circuits: miniature or molded case breakers sized to capacity, three-phase four-wire output
- Enclosure: wall-mounted / outdoor floor-standing, IP54 standard, IP65 for washdown areas
- Components: Schneider / ABB / Siemens / Chint; brand can be specified, or customer-supplied components shipped to our plant
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.
| Enclosure type | Wall-mounted / floor-standing (outdoor with base) |
|---|---|
| Standard dimensions (W×H×D) | 500×600×200 (wall-mounted) to 1000×1200×400 (floor-standing) mm, custom sizes available |
| Enclosure construction | 1.5–2.0 mm cold-rolled steel, bent and welded, electrostatic powder coated |
| IP rating | IP54 standard / IP65 (washdown or outdoor) |
| Door and operation | Control circuit pushbuttons / indicator lights door-mounted or cut into the enclosure face |
| Cable entry | Bottom cable entry/exit, glands sized to cable outer diameter |
| Rated voltage | AC 380V / 400V, 50 Hz |
|---|---|
| main breaker | Molded case circuit breaker ≤400 A, optional residual current / undervoltage trip |
| Motor circuits | Breaker + contactor (AC-3) + thermal overload relay, local start/stop |
| Feeder circuits | Miniature / molded-case circuit breakers, 2–12 ways, three-phase four-wire |
| Metering and indication | Voltmeter / ammeter / run indication fitted as required |
| Remote interface | Spare dry contacts for remote start/stop and a run feedback signal |
| Component brands | Schneider / ABB / Siemens / Chint; customer-supplied components accepted for factory installation |
| Single-equipment local box | One box per equipment item: local power distribution and control for pumps, fans and air compressors |
|---|---|
| Equipment group control box | Centralized control for multiple small equipment items: independent protection per way plus interlock logic |
| Outdoor pump house box | IP65 plus anti-condensation heater, automatic start/stop on liquid level |
| Sub-distribution box downstream of the electrical room | Second-level workshop distribution fed from the power cabinet |
| Division of work with the power cabinet | Floor-standing power cabinets handle centralized distribution in the electrical room; this box handles local power take-off next to the equipment |
| Assembly standard | GB/T 7251.1 / IEC 61439-1 |
|---|---|
| Routine tests (every unit) | Insulation resistance, dielectric withstand and circuit-by-circuit energization and operation tests |
| Temperature rise | Terminal and busbar connections ≤70 K |
| Ingress protection verification | For outdoor types, door seals and cable glands checked against water spray |
| Documents with shipment | System diagram, terminal schedule, BOM, test report |
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.
One motor circuit per column
Each motor circuit has its breaker, contactor and thermal overload relay grouped vertically; circuit numbers match the on-site equipment tags, so maintenance does not require tracing wires.
Pushbuttons mounted on the enclosure face
Controls for equipment mounted right beside it go on the enclosure face: start/stop, indication, and manual/auto switching in one place — no opening the door to work on live parts.
IP65 starts at the door gasket
For washdown environments: double-layer door gasket + waterproof hinge caps + bottom cable glands. It genuinely takes a direct spray, not just on paper.
Outdoor enclosures with heater
Outdoor enclosures in climates with wide day-night temperature swings get an anti-condensation heater with thermostat. No condensation at dawn, no green copper on components.
Energized operation checked one by one
Every circuit is powered and function-tested; contactor pull-in and protection settings are verified together.
Channel steel base for floor-standing enclosures
Floor-standing enclosures sit on a channel steel base with expansion bolts. The load goes through the base, not the door frame — a knock won't distort it.
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.
Pump houses and water treatment stations
Local pump start/stop control; automatic level control optional.
Air compressor rooms
Local power distribution and interlocking for air compressors.
Workshop equipment clusters
Several small machines grouped on one enclosure with zoned protection.
Outdoor irrigation and pump stations
IP65 + anti-condensation heater, running year-round.
Production line workstation power
Mixed circuits for workstation power and maintenance receptacles.
Secondary distribution from the electrical room
Local workshop distribution fed downstream from the power cabinet.
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
Power distribution box or power distribution cabinet — which one?
It comes down to mounting location and capacity: for local power takeoff beside equipment with a main breaker under 400 A, use a box (wall-mounted or small floor-standing). For centralized distribution in an electrical room with many circuits and high capacity, use a floor-standing power cabinet. The two often work together: the cabinet distributes in the electrical room, the boxes take power locally in the workshop.
Why must a motor circuit include a contactor?
The contactor handles frequent starting/stopping and remote control; the breaker provides short-circuit protection only and is not meant to switch frequently; the thermal overload relay handles overload — each does its own job. Skip the contactor and operate directly with the breaker, and the breaker contacts burn out fast. This is the most common false economy on site.
What matters for outdoor installation?
IP65 door gasket + bottom cable gland entry is the baseline. You also need condensation control (day-night temperature swings do more damage to components than rain) — add an anti-condensation heater. Add a sun shield where there is direct sunlight. For coastal or aquaculture sites, specify a stainless steel enclosure.
Can you do automatic level or pressure control?
Yes. Add a level/pressure controller or a small PLC inside the enclosure for automatic pump start/stop. Send us your control requirements (number of level points, level transmitter type) and we will draw the control circuit into the system diagram.
How many circuits can an enclosure hold?
It is calculated from circuit current and heat dissipation: a standard wall-mounted enclosure takes 2–8 circuits, a floor-standing enclosure up to 12. Beyond that, split into multiple enclosures or move up to a floor-standing cabinet. Heat is a hard constraint — cram in extra circuits and you will get nuisance tripping in summer, no question.
How do you interface when replacing an old enclosure?
Send photos of the old enclosure plus a circuit list. We produce drawings 1:1 against the original cable entry/exit positions and circuit numbers, so existing cables land in place and the swap is done in half a day.
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.
Send us your equipment list — we lay out the circuits to match
Send us your equipment list (power rating / quantity / control requirements) and we will provide a free circuit design and enclosure layout · quotation within 24 hours. Direct from the source factory, MOQ 1 unit, 15–25 day lead time, 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.