1. What determines the size of an equipotential bonding terminal box? 3 variables
Equipotential terminal boxouter dimensionsare determined by 3 variables:
- Terminal count: 5 / 6 / 8 / 12-way options; more ways means a larger terminal box
- Installation: surface-mount (mounted on the wall face) and flush-mount (recessed into the wall) have different profiles; flush-mount requires a pre-formed wall opening
- Terminal block spec: small terminals (4 mm² conductor) and large terminals (6 mm² conductor) differ in size
Zhejiang Golden Unicorn defaultT2 copper terminal block, nickel-plated, each terminal rated 63A, accepts 4 / 6 mm² copper conductors.
2. Quick-reference table: 5 / 6 / 8 / 12-way terminal box specs (W × H × D mm)
| Terminals | Surface-mount outer dimensions (mm) | Flush-mount wall opening allowance (mm) | Application |
|---|---|---|---|
| 5-way | 180 × 180 × 70 | 160 × 160 × 65 | Single bathroom / simple residential |
| 6-position | 200 × 200 × 70 | 180 × 180 × 65 | Standard bathroom / shower room |
| 8-way | 250 × 250 × 70 | 230 × 230 × 65 | Large bathroom / sauna |
| 12-way | 300 × 300 × 80 | 280 × 280 × 75 | Swimming pool / hospital / commercial |
Flush-mount wall opening = surface-mount outer dimensions − 10 mm per side; flush-mount depth allowance = surface-mount depth − 5 mm (leave 5 mm behind the box for heat dissipation). Example: 6-way surface-mount 200×200×70 → flush-mount wall opening 180×180×65.
3. Surface-mount vs. flush-mount: dimensional differences Wall thickness determines whether flush mounting is possible
A flush-mount terminal box must be recessed into the wall,so the wall must be at least 80 mm thick(65 mm box depth + 15 mm clearance). If the wall is a 60 mm lightweight partition, surface mounting is the only option.
A surface-mount terminal box comes with its own back box and is fixed directly to the wall; a flush-mount terminal box has no back box and must be recessed into a wall opening.
| Item | Surface mount | Flush mount |
|---|---|---|
| Appearance | Protrudes from the wall | Flush with the wall |
| Wall thickness required | Any | ≥ 80mm |
| Installation difficulty | Low | High (wall opening required) |
| Aesthetics | Poor | Good |
| Price | Slightly lower | Slightly higher |
4. How to set the mounting height GB 50096 and local codes
Equipotential terminal boxMounting heightDepends on the application:
| Location | Mounting height | Golden Unicorn recommendation |
|---|---|---|
| Bathroom | 0.3–0.5 m above floor | Surface mount 0.4 m / flush mount 0.3 m |
| Washroom | 0.3–0.5 m above floor | Surface mount 0.4 m / flush mount 0.3 m |
| Hospital operating room | 0.5–0.8 m above floor | Flush mount 0.5 m |
| Pool equipment room | 0.5–1.0 m above floor | Surface mount 0.6 m |
equipotential bonding terminal boxInstall where wiring to water pipes, faucets, or shower heads is convenient— usually below the washbasin or behind the shower valve. For flush mounting, the wall opening must be planned in advance; the position cannot be changed later.
5. Five Common Questions About Equipotential Bonding Terminal Box Selection (Quick Answers)
FAQ FAQ
Is a 5-position terminal box enough?
No.A standard bathroom needs 6 positions (shower + cold water pipe + hot water pipe + faucet + bathtub + spare). 5 positions is a reduced configuration, suitable for retrofit projects / older buildings.
What applications use a 12-position terminal box?
Large-scale applications: swimming pools, hospital operating rooms, bathrooms in commercial complexes. 12 positions can connect 8–10 metal parts + 2–4 spare terminals.
How much does the price differ between surface-mount and flush-mount terminal boxes?
20–30% difference. Flush-mount requires embedding into the wall, with a thicker box body and more accessories. If wall thickness allows, flush-mount is recommended for a cleaner look.
What material are the terminals in the terminal box?
Zhejiang Golden Unicorn default T2 copper terminal block, nickel-plated. Each terminal has 2 screws, accepts 4 / 6 mm² copper conductors, current-carrying capacity 63A, compliant with GB 14048.7.
Does the terminal box require 3C certification?
The terminal box itselfdoes not require mandatory 3C; however, if installed in a hazardous area (explosion-proof zone), it must be manufactured to explosion-proof standards. Zhejiang Golden Unicorn can supply both non-explosion-proof and explosion-proof terminal boxes, MOQ 1 unit, 15–25 days.
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