Electrical cartons fill a container by volume or by weight depending on the mix: dense breaker cartons run into weight limits, while enclosures and boards are bulky and run into volume limits. Calculate CBM per carton (length × width × height in metres), add them up, plan on roughly 28 usable CBM in a 20 ft container and about 68 in a 40 ft high-cube, then confirm against the audited packing list.
Key facts
- CBM = L × W × H of one carton in metres, multiplied by the number of cartons.
- Practical (not theoretical) volume is lower than internal volume because cartons never tessellate perfectly: roughly 28 CBM in a 20 ft container and 68 CBM in a 40 ft high-cube. Payload limits are roughly 26–28 tonnes — confirm with your carrier.
- Many forwarders suggest FCL once a shipment approaches about 15 CBM; below that, LCL is often cheaper.
Worked example
| Step | Calculation | Result |
|---|---|---|
| One carton | 0.60 m × 0.40 m × 0.30 m | 0.072 CBM |
| 1,000 such cartons | 1,000 × 0.072 | 72 CBM — more than one 40 ft high-cube can hold |
| Weight check | cartons × gross weight (kg) | Must stay under the container payload |
The figures are for illustration. Your real carton sizes and gross weights come from the supplier’s packing list.
Volume-bound or weight-bound?
| Cargo | Usually limited by | Why |
|---|---|---|
| MCBs, RCBOs, contactors | Weight | Small, dense cartons carry a lot of metal |
| Distribution boards, enclosures | Volume | Large, light, hard to stack |
| Mixed breakers + boards + cable accessories | Whichever fills first | Plan the mix so both limits are reached together |
Mixed electrical cartons eat space fast, so landed cost is won or lost on packing density. This is one reason buyers consolidate in Yiwu instead of collecting from several factories — see why Yiwu works for mixed orders.
Documents for a mixed container
- Commercial invoice with ordering codes and quantities.
- Packing list with cartons, pieces per carton, gross weight and CBM per line.
- Bill of lading.
- Product certificates for each ordering code required by your destination (see import certificates by country).
Terms we quote
FOB, CFR or CIF Ningbo or Shanghai as standard, with DDP on request. We photograph your specific cartons and audit the packing list before loading. For a first plan, send your line list and destination and we return packing data with the quotation.
Frequently asked questions
How many CBM fit in a 40 ft container?
About 58 CBM practical in a standard 40 ft and about 68 CBM in a 40 ft high-cube, depending on how well the cartons stack. Always confirm with the audited packing list.
Should I ship FCL or LCL?
Small shipments usually go LCL. As volume approaches roughly 15 CBM, FCL often becomes cheaper per CBM and reduces handling.
Can breakers and boards go in the same container?
Yes — that is the point of consolidation. Plan the mix so weight and volume limits are reached together.
Get a real quotation, not a brochure.
Send model or photo · quantity · destination country · grid (V / Hz / 1φ or 3φ) · required certificate. You get unit price, packing data (carton / pcs / GW / CBM), lead time and the certificate list in one message, within 24 hours.
Reviewed by the HAZAM technical team, October 2026. CHINT, DELIXI and TENGEN are trademarks of their respective owners. HAZAM is a first-tier authorised distributor of CHINT products; the authorisation certificate is available on request from our sales manager. Ratings and designations refer to published manufacturer documentation; the certificate for your exact ordering code governs.