Junction boxes / terminal boxes
- Terminals: Weidmüller / Phoenix-style terminal blocks, specifications selected by current, solid connections
- Identification: wire number sleeves + terminal numbering, matched one-to-one with drawings for easy maintenance
- Material: carbon steel / stainless steel 304/316L, wall-mount / floor-standing optional
- Protection: IP54 / IP65, suitable for outdoor and damp environments
- Customization: terminal count, incoming/outgoing cable routing, and cutouts built to drawing
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.
| Box Type | Junction box / terminal box, wall-mount / floor-standing, single door |
|---|---|
| Material | Cold-rolled carbon steel (powder-coated) / stainless steel 304 / 316L |
| Standard dimensions | Wall-mount 300×300×150 to 800×600×250 mm; floor-standing up to 800×600×1800 mm, custom sizes available |
| Enclosure construction | Sheet steel bent and welded, outdoor models with door gaskets |
| Surface treatment | Degreasing, derusting, phosphating → electrostatic powder coating (carbon steel) / bare stainless steel |
| IP rating | IP54 / IP65 (outdoor and damp environments) |
| Cable entry | Bottom / side cable glands or cutouts, quantity and position built to drawing |
| Door and lock | Flush lock, transparent viewing window optional |
| terminal blocks | Weidmüller / Phoenix-style terminal blocks, specifications selected by circuit current |
|---|---|
| Terminal type | Standard terminal blocks, grounding terminals, fuse terminals, current transformer terminals |
| Marking | Wire markers + terminal numbering, mapped one-to-one to drawing point numbers |
| Equipotential bonding | Equipotential bonding bar (MEB / LEB), tying in grounding from all locations |
| Grounding | Enclosure grounding terminal + grounding busbar, grounding continuity tested |
| Component brands | Weidmüller / Phoenix / Chint, or as specified on the drawing |
| Cable transition box | Multiple cable entries, transitioned through terminal blocks then split to outgoing lines |
|---|---|
| Equipotential bonding box | MEB / LEB equipotential bonding, tying in grounding |
| Grounding terminal box | Grounding terminals grouped together, grounding system tie-in |
| Signal junction box | Transition wiring for analog / communication signal lines |
| Outdoor terminal box | Outdoor terminal box, IP65 rainproof |
| Build-to-drawing custom box | Built to drawing for terminal count, incoming/outgoing lines and cutouts |
| Reference standards | GB/T 7251.1 / IEC 61439-1 (assemblies); GB/T 7251.3 (distribution boxes) |
|---|---|
| Terminal standard | Terminal specifications meet applicable electrical connection standards |
| IP rating | GB 4208 / IEC 60529, IP54 / IP65 |
| Insulation resistance | ≥1 MΩ (500V megohmmeter) |
| Power frequency withstand voltage | Main circuit 2500V / 1 min, control circuit 1500V / 1 min |
| Factory tests | Terminal wiring check, dielectric withstand, grounding continuity, seal inspection |
| Documents with shipment | Wiring diagram, terminal schedule, 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.
Terminal contact compression
Terminal contact compression, tightened to specified torque. A loose contact means heat and oxidation — the most hidden failure point inside the box.
Wire and terminal numbering
Every wire gets a number sleeve, and terminal numbers match the drawing one-to-one. Later maintenance can trace it against the drawing instead of testing wire by wire with a meter.
Terminals sized to current
Terminal specifications are selected according to circuit current — no cutting corners with undersized terminals. If terminal capacity falls short, high current means heat.
Centralized bonding bar termination
The equipotential bonding bar brings all grounding points together at a single point. The reliability of the grounding system depends entirely on how solid that point is.
Fully sealed outdoor version
Outdoor terminal boxes get door seam sealing + cable glands, IP65. When an outdoor box takes on water, the terminal block is the first to suffer.
Terminal wiring per drawing
Terminal quantity, incoming/outgoing cable routing, and cutouts are all built to drawing. Junction boxes are essentially custom builds — standard parts won't match.
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.
Building electrical
Cable transition and equipotential bonding for floors and equipment rooms.
Industrial power distribution
Cable distribution and wiring transition for workshops and equipment.
Grounding systems
Centralized grounding terminal layout and equipotential bonding.
Outdoor facilities
Outdoor terminal boxes, IP65 rainproof.
Signal systems
Transition wiring for analog and communication signal cables.
Build to drawing
Built to drawing for terminal quantity, incoming/outgoing cable routing, and cutouts.
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 junction box and a terminal box?
They are basically the same category under different names. Both are used for cable transition wiring and contain terminal blocks inside. By convention, a junction box tends to be smaller and a terminal box larger; equipotential bonding boxes and grounding terminal boxes are specialized variants.
What does an equipotential bonding box do?
It brings grounding conductors from various points of a building or equipment together at a single point (MEB main equipotential bonding / LEB local equipotential bonding), ensuring the entire grounding system sits at a consistent potential to prevent electric shock and lightning damage. It is standard practice in building electrical and industrial grounding.
How are terminal specifications selected?
Selected according to circuit current and wire gauge — the terminal's rated current must exceed the circuit current. Send us the circuit schedule or current values and we will help you select terminal specifications.
Can it be used outdoors?
Yes. Outdoor terminal boxes are built to IP65, with gasketed door seams and cable gland entries. They hold up long-term in damp and rainy conditions.
Can you build it to my terminal count?
Yes. Terminal count, cable entry method and cutouts are all built to drawing. Send us your terminal schedule and cable entry requirements and we will come back with a design.
What do you need for a quote?
Box type (wall-mount / floor-standing), material, ingress protection (IP) rating, terminal count and specifications, cable entry method, application (transition / equipotential bonding / grounding / signal). Drawings are preferred if you have them.
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.
Cable transitions, grounding and bonding — configured to your terminal schedule
Send us your terminal schedule and cable entry requirements for a free junction box / terminal box design · quotation within 24 hours. Direct from the 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.