Cable Drum Length, Packing and International Shipping

How does drum length affect joints, weight and handling?

Drum length decides how many joints an installation needs. Each field joint needs its own jointing work, testing and time, so longer continuous lengths reduce the number of joints on a route. The trade-off is weight and size: a longer length means a larger, heavier reel that has to be moved, lifted and unwound on site.

Before approving a length, check the route section lengths, the pulling limits for the cable (see cable installation, bending and pulling), the crane or lifting capacity at the destination and the container dimensions. A length that works on paper can still fail at the site crane or at the container door.

Conductor metal is the largest part of the weight. As a basis for estimates, copper has a density of 8.89 g/cm³, which means about 8.89 kg per km per mm² of conductor cross-section. Aluminium has a density of 2.70 g/cm³, which means about 2.70 kg per km per mm². Insulation, sheath, armour and the drum itself add to the total, so ask the supplier for the gross drum weight.

Is a longer drum always better?

No. A continuous length reduces joints, but it may create a reel that is too heavy for the destination crane or too large for the container. A shorter drum may need more joints, and each extra joint adds work and a point that must be inspected later. The right length balances joint count, route sections, pulling limits and handling capacity together.

Drum limits can also affect what can be manufactured. Confirm packaging before production starts, because drum limits can change the manufacturable length. Ask the supplier which drum sizes it proposes for the requested lengths and how the drum schedule will be checked.

Which drum construction suits international shipment?

Wood, steel-wood and steel reels can all be used. The choice depends on cable weight, return arrangements and the destination's rules. Heavier cables usually need stronger reels, and if drums are to be returned, the return arrangement can also influence the reel type.

Timber used in wooden or steel-wood reels may need treatment or a declaration for international shipment. Rules differ by destination country, so ask the supplier to confirm which documents and timber treatment apply before the drums are built, not after they arrive at port.

What should the drum schedule record?

A drum schedule links each drum to a line item, length and weight, so the buyer can check the order against the goods received. The table lists the items to agree before production starts.

Drum dimensions, weights and lengths depend on the cable and the supplier's reel range. Confirm them for each line item in the drum schedule rather than relying on a general figure.

Approve the drum schedule line by line, and check the container door and payload limits before the container is booked. For the wider order steps, see what to check before shipping cable orders.

How should drums be sealed, marked and unloaded?

Seal the inner and outer ends of the cable and cap them against moisture. Secure the outer layer so the wound cable does not loosen, and protect the cable from impact during handling and transport. Damage to the ends or outer layer is often found only when the drum is opened on site.

Labels should show the model, size, length, drum number, weights and handling direction. Use the same drum numbers in the packing list and shipping documents so the buyer can trace each drum.

In the container, block and brace the drums so they cannot roll or shift. At destination, unload with an axle or a lifting method suited to the reel, and never drop drums from a vehicle. Ask the supplier for written unloading instructions and pass them to the receiving team.

Frequently asked questions