HomeTechnical notes › PZ30 Distribution Box Size Chart: Surface/Flush Mount and Circuit Count Reference

05 Informational content / Technical articles 2026-09-11 Published ~ 11 min read GB/T 7251.12 · GB 7251.3

PZ30 Distribution Box Size Chart
Surface/Flush Mount and Circuit Count Reference

PZ30 is the most widely used terminal distribution box for homes and offices. This article providesthe complete PZ30 size chart: surface mount vs. flush mount, circuit counts, and DIN rail positions, with selection advice. Zhejiang Golden Unicorn produces 2,000+ terminal boxes per year,MOQ 1.

1. What Is a PZ30 Box? (Terminal Combination Apparatus)

PZ30 = Modular terminal distribution box, fitted with miniature circuit breakers (MCB), used for final-stage distribution in homes and offices, rated current ≤ 63A. Advantages include DIN rail mounting and flexible circuit combinations.

SCHEMATICBusbarsTerminal blocksMain circuit breakerControl & protection devicesTerminal block outgoing cables
Figure — 1. What Is a PZ30 BoxCabinet structure diagram · photo pending

2. PZ30 Size Chart (by Circuit Count)

Circuitsthe number of polesSurface Mount (mm)Flush Mount (mm)Height
66210×150×80200×140×8080
1212300×240×100280×220×9090
1818400×300×100380×280×9090
2424480×320×100460×300×90100
3636600×400×120560×360×100120

3. Surface Mount vs. Flush Mount (How to Choose)

Selection

Flush mountClean look (flush with wall), requires a pre-formed wall opening;Surface mountSimple installation, enclosure protrudes 80–100mm from the wall. Choose flush mount for new construction, surface mount for renovations.

4. How to Determine Circuit Count (by Appliance)

  1. Lighting 1 circuit + 1 spare
  2. Sockets 2–3 circuits (separate general/kitchen/AC)
  3. Dedicated AC circuits 1–2 (floor-standing/wall-mounted)
  4. 1 dedicated circuit per high-power appliance (water heater/oven)

5. PZ30 Buying Guide (3 Things to Check)

① Checkthe number of poles(circuits × 1 or 2 poles); ② Checkthe breaker brand(Schneider / Chint / ABB); ③ Checkthe enclosure material(powder-coated steel / stainless steel / ABS plastic).

FAQ FAQ

What is the maximum number of circuits for a PZ30?

36 circuits is common; for more, use an XL-21 power distribution box.

How large an opening should be left in the wall for a flush-mounted PZ30?

Enclosure outer dimensions + 10 mm clearance on all sides.

Can a PZ30 take an RCD?

Yes. Each circuit can have an MCB + RCD module, or a single main RCD.

What is the difference between PZ30 and PZ40?

The PZ40 has a higher ingress protection (IP) rating (IP40) and a similar structure; it is mainly used in damp environments.

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