Floor distribution boxes
- Branches: unit circuits + common circuits (lighting / telecom room / common AHU section) on separate branches
- Metering position: unit meter position can be embedded in the enclosure (meters configured and verified by the utility or property management)
- Riser shaft design: surface-mounted, usable depth set by cable bending radius, top and bottom cable entry
- Lightning protection: SPD module slots reserved per building lightning protection classification (Type 2 as standard)
- Components: Chint / Schneider / ABB; 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 | Surface-mounted in riser shaft (standard) / flush-mounted in floor |
|---|---|
| Standard dimensions (W×H×D) | 600×800×200 to 800×1600×250 mm, custom sizes available |
| Enclosure construction | 1.5–2.0 mm cold-rolled steel, front and rear doors (large enclosures) for riser shaft maintenance |
| IP rating | IP30 (inside riser shaft) / IP54 (semi-basement / garage level) |
| Segregation | Main busbar compartment / branch compartment / metering compartment, compartmentalized (metering optional) |
| Cable entry | Top / bottom vertical main busbar entry, branch exits on the side |
| Rated voltage | AC 220/380V, 50 Hz |
|---|---|
| main breaker | Isolator / circuit breaker 100–400 A (per floor load) |
| Per-unit circuit | 4–24 independent unit breakers (1P+N / 3P+N per unit capacity) |
| Common circuit | Common lighting / elevator lobby / low-voltage room / garage on separate sections |
| Metering position | Unit meter positions embeddable (metering and sealing by utility / property management) |
| SPD position | Reserved position for Type 2 surge protection module (building lightning protection zoning) |
| Equipotential bonding | PE bar and riser grounding busbar connection terminals clearly labeled |
| Component brands | Chint / Schneider / ABB / Siemens, customer-supplied and shipped to factory accepted |
| Residential floor type | Per-unit + common lighting + low-voltage room, vertical main busbar by zone |
|---|---|
| Apartment / hotel type | Dense unit positions + corridor and common sections on separate circuits |
| Office floor type | Zoned socket outlets + lighting + air conditioning common sections on separate circuits |
| Garage floor type | Parking space circuits and reserved EV charging station positions (subject to capacity assessment) |
| Retrofit cabinet replacement type | 1:1 replacement per original circuit, riser dimensions verified on site |
| Assembly standard | GB/T 7251.1 / IEC 61439-1 |
|---|---|
| Routine tests (every unit) | Insulation resistance, dielectric withstand, circuit-by-circuit continuity test |
| Temperature rise | Terminal and busbar connections ≤70 K |
| Label verification | Circuit labels (unit number / zone) checked against system drawing cabinet by cabinet |
| Documents with shipment | System drawing, circuit cross-reference table, 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.
Faults stay within the unit
Unit and common-area circuits are compartmented and labeled separately: a trip in one unit never disturbs a neighbor, and property maintenance can locate the fault fast — the baseline for any floor-level cabinet.
Usable depth set by bend radius
Shaft risers are thick and have large bend radii, so the usable depth of the enclosure is designed around the actual cable diameter rather than forced to fit: a crushed cable loses ampacity and runs hot — an easy trap to fall into.
Circuit number matches unit number
Circuit labels correspond one-to-one with unit numbers / zones, and the laminated system diagram is affixed inside the door: property management can maintain the system without relying on a veteran technician's memory.
Surge protection in one step
Provision for a Type 2 SPD module position (plug-in type, individually replaceable): not every floor in a building needs surge protection, but leaving the position ready means acceptance testing or a later retrofit does not require replacing the enclosure.
PE connected first
The PE bar and the shaft grounding riser connection terminals are labeled up front and continuity-tested on every unit: grounding in a floor-level cabinet is the capillary system of whole-building safety — invisible, but it cannot be weak.
Parking circuits reserved first
Garage-level cabinets reserve EV charging circuit positions according to the number of parking spaces (breakers installed later): a new energy retrofit then only requires adding breakers, not replacing the enclosure — doing it in one step costs far less than a later enclosure swap.
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.
Residential floors
Unit and common-area circuit distribution, with vertical risers zoned.
Apartments and hotels
Dense unit positions, with corridor common sections separated.
Office building floors
Zoned socket outlets and common air-conditioning sections.
Retail Floor
Separate circuits for retail bays and common-area lighting.
Parking Level
Parking stall circuits with reserved capacity for EV charging.
Older Building Retrofit
1:1 circuit-for-circuit box replacement; shaft dimensions verified on site.
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
How do floor boxes and in-unit boxes split the work?
Floor box in the riser shaft: distributes the vertical feeder to that floor plus common-area circuits. In-unit box inside the unit: final branch circuits for lighting and receptacles. Which level carries metering depends on the local utility's service plan (unit meters embedded in the floor box, or a separate meter box) — we issue drawings to that plan.
The riser shaft is tight — can the enclosure be made thinner?
Usable depth is set by cable bend radius: a feeder of 95 mm² or larger already needs a bend radius over 200 mm, so a thinner enclosure forces a hard kink in the cable. The right approach is to set usable depth from the actual cable diameter, and where needed use front and rear doors with pass-through routing — not to shave depth without limit.
How many circuits does one floor need?
Residential: number of units + common-area lighting + telecom room + 20% spare. Office: calculated by zone area and HVAC section. Send us the floor plan and we will issue a circuit schedule — that part is free.
Can meters be embedded?
Yes: unit meter positions are punched to the local meter type (send us the meter model to verify), and the metering compartment and wiring compartment have separate doors and locks, with seal positions left for the utility / property management — the responsibility structure is set up front so there is no dispute later.
Does every floor need surge protection (SPD)?
Per the building's lightning protection class: on the low-voltage side, typically one stage at the main box plus a second stage on critical floors — not on every floor. We leave the module positions pre-installed (plug-in type), so additional stages can be added at acceptance or during retrofit without replacing the box.
Does replacing boxes in an old building require shutting down a whole floor?
With a 1:1 circuit replica, changeover can be done unit by unit: common-area circuits switched during the day, branch circuits switched unit by unit in the evening, keeping the whole-floor outage window as short as possible. The retrofit plan is issued with the changeover sequence, and property management only needs to notify residents in advance.
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 the floor plan — circuit schedule issued free
Send the floor plan or unit count and we will issue a free circuit plan and enclosure dimensions · 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.