A cable drum, also called a reel, is the wooden or steel spool on which cable, wire and rope are delivered. Wooden drums are built from flanges (discs) joined by a barrel (the core) and are produced to national and company standards; in Germany DIN 46391 sets dimensions for delivery drums. Because they contain solid wood, wooden drums that cross borders are subject to ISPM 15, and they are usually reused several times before being scrapped.
What a cable drum is
A delivery drum protects the cable from damage during storage and transport, and lets it be unwound under control at the installation site. Drums are specified by:
- Flange diameter, the overall outer diameter of the discs,
- Traverse width, the distance between the inner faces of the flanges,
- Barrel (core) diameter, which sets the minimum bending radius of the cable, and
- Load capacity, the maximum gross weight the drum can carry.
Getting the barrel diameter right is important, because winding a cable around a core smaller than its minimum bending radius can damage the insulation or conductors. Drums range from small reels for wire and light cable to large drums for submarine, power and telecom cable.
Construction of wooden drums
A typical wooden drum has these parts:
| Part | Function | Usual material |
|---|---|---|
| Flanges | Side discs that retain the cable | Boards laid in two or more layers and nailed crosswise, or plywood |
| Barrel | Core on which cable is wound | Staves or battens around a hub, or a solid wooden core |
| Hub and bolts | Central axle opening and connecting bolts that hold flanges and barrel together | Steel bolts and washers |
| Lagging | Boards or foil wrapped around the finished drum to protect the cable | Wooden battens, plastic or board sheeting |
Flanges built from crossed board layers resist splitting and keep their shape under the radial load of the wound cable. Larger drums use stronger bolts, extra hoops or steel reinforcement. Lagging closes the outer surface so the cable is protected from impact and forklift damage during transport.
DIN 46391 and other standards
DIN 46391 is a German standard for delivery drums for cables and conductors. Its part 1 covers drums with flange diameter up to 2,800 mm (110 in) and part 3 covers drums with flange diameter above 2,800 mm. The standards define dimensions so that drums from different makers fit cable-laying equipment and so that users can specify them by size. Other countries and industry groups use their own standards or manufacturer ranges, and large cable producers often have drum catalogs of their own, so the drum type should be agreed in the purchase specification rather than assumed.
Wood, steel and plastic drums
| Type | Advantages | Limitations |
|---|---|---|
| Wooden | Low cost, easy repair, wide range of sizes, recyclable | Needs ISPM 15 compliance for export, sensitive to moisture and mould, heavier than plastic in smaller sizes |
| Plywood | Smooth flanges, lower weight for small and medium sizes | Less suited to very heavy cable |
| Steel | Very robust, long service life, suited to returnable circuits | High cost and weight, needs to be returned and tracked |
| Plastic | Light, uniform, weatherproof | Higher cost, limited sizes, hard to repair |
Cable producers often choose steel for returnable, high-turnover circuits and wood for one-way or occasional deliveries. See wood vs plastic pallets for the broader comparison of wood and plastic in load carriers.
ISPM 15 and international shipping
Wooden drums are wood packaging material, and a drum made of solid wood that is exported must carry the ISPM 15 mark with country code, producer number and treatment code (HT, for example). The mark must be clear and permanent. Plywood and other processed wood panels made with glue, heat and pressure are exempt; drums built from them need no treatment, but any solid wood parts still do. See ISPM 15 explained, the ISPM 15 mark guide and ISPM 15 exemptions.
Drums that were repaired with untreated wood lose their compliance, so repaired drums must be re-treated and re-marked. That rule is described in reused and repaired wood packaging.
Return systems and reuse
Drums are expensive relative to a pallet and are used many times when circulation is organized. Common models are:
- Returnable circuits, where the cable maker or distributor takes back empty drums, inspects them, repairs them and reuses them.
- Deposit schemes, where the customer pays a deposit refunded when the drum is returned.
- One-way drums, where the drum is scrapped by the customer after installation.
Return systems depend on drums staying identifiable: owner markings, serial numbers or branding on the flange help recovery. See pallet branding and marking for marking methods that also apply to drums.
End of life
When a drum cannot be repaired it is dismantled, and its wood is recycled or burned. In German practice, the waste wood ordinance AltholzV lists cable drums by age in the annex of typical assortments: according to the published annex, those manufactured after 1989 fall in the least contaminated category A I, while older drums are classed as A IV. Steel drums are recycled as scrap. For the wider routes see pallet wood waste as biomass and raw material.
Frequently asked questions
What is DIN 46391?
It is a German standard that defines dimensions of delivery drums for cables and conductors. Part 1 covers flange diameters up to 2,800 mm and part 3 covers diameters above 2,800 mm.
Do wooden cable drums need ISPM 15 stamps?
Yes, if they contain solid wood and cross an international border. Drums made only of plywood or similar processed panels are exempt.
Why is the barrel diameter important?
Because the cable has a minimum bending radius, and winding it on a smaller core can damage the cable.
Are wooden drums reusable?
Yes. They can be returned, inspected and repaired many times, provided the repaired parts are treated and marked where ISPM 15 applies.
Sources
- DIN 46391-1: Delivery drums for cables and stranded conductors, part 1 — DIN Media
- DIN 46391-3: Delivery drums for cables and ropes, part 3 — DIN Media
- Annex 3 AltholzV: assignment of common waste wood assortments — anwalt24.de
- ISPM 15 (2018): Regulation of wood packaging material in international trade — International Plant Protection Convention