Storing cable and conductor so it keeps its value

The first hour decides most of it

The condition a reel reaches after five years is mostly set in the first hour after it comes off the truck. Cable arrives warm from a plant, wrapped, with sealed ends and a tag. If it goes straight onto dunnage, upright, with the ends still sealed and the tag recorded, it will still be a usable product years later. If it is rolled off the side of a truck onto gravel, left on its side and opened at one end to look at the conductor, the clock starts on damage that cannot be undone.

The minimum routine is short. Note the tag before it fades. Cap or tape the ends. Stand the reel on its flanges on something that is not mud. Chock it so it cannot roll. Put the identification somewhere that survives weather.

Everything else in this guide is elaboration on those five actions, and a yard that does them consistently will get a materially better price for the same cable than a yard that does not — not because buyers are generous, but because the material is genuinely better.

Orientation and blocking

Reels are built to carry their load on the flanges, with the drum axis horizontal. Stood that way, the cable rests on the barrel and the flanges take the weight through the hub. Laid flat, the load goes onto the side of the wound cable, the outer layers take the whole mass of the reel, and the flange takes a point load it was never designed for. A reel stored flat for a season can arrive with a flattened section of jacket, ovalised insulation and a cracked flange.

Put reels on dunnage — timber, pallets or a concrete pad — so the flanges are not sitting in standing water. Grade the ground or choose the high side of the yard. Chock both flanges, and on anything above a modest size use two chocks per side rather than one. If the reel has a rolling-direction arrow on the flange, honour it when you move it; rolling a reel against its wind can loosen the outer layers.

Where reels must be stacked, the only tolerable arrangement is upright on a rack or cribbing that carries the flanges, never a reel lying on top of another reel's cable. Even then, a heavy reel on a light one deforms the lower reel's flange, and a deformed flange no longer protects the cable. If there is no rack, do not stack; buy or borrow more ground.

Water is the expensive problem

Water does not need to flood a reel to do damage. It needs an open end and time. Once moisture reaches the conductor strands it travels along them by capillary action, well past the point where the jacket ends, and it takes the shield and the insulation with it. On medium-voltage XLPE cable, moisture in the presence of an electric field is what produces water trees — the branching, microscopic degradations that end with a cable failing in service. A cable that has been wet inside cannot be sold for reuse honestly, and a buyer who finds water staining in the ends will price accordingly.

The defenses are simple and cheap. Cap every end, including the ends that were cut at the factory, and re-cap after any cut. Heat-shrink caps are best; a good wrap of self-amalgamating tape over a clean, dry end is acceptable; a rag stuffed in the end is not. Store reels so the ends are not at the low point of a puddle, and never lay a reel with an open end facing up.

Aluminum and steel-cored conductor have their own version of the problem. Water in a stranded aluminum conductor produces white oxide and eventually pitting; water in an ACSR core rusts the steel from the inside, where no inspection will find it until the conductor fails or a buyer cuts the end. On bare conductor stored outdoors, the ends are the first thing to check when a drum is being assessed.

Sun, heat and jacket life

Sunlight is the second slow thief. Ultraviolet light attacks the polymer at the surface of a jacket, breaking the chains that give it flexibility. Black jackets with a proper carbon-black loading resist this well, which is why most outdoor-rated cable is black; other colors and thin jackets degrade faster. The visible signs are chalking, a color shift, fine surface cracking, then cracking deep enough to reach a shield or a neutral. Once the jacket has cracked through, the cable is no longer a listed assembly, whatever the conductor inside is doing.

Heat adds to it. A reel standing against a dark wall in full afternoon sun gets considerably hotter than the air temperature, and a reel standing in a puddle gets water at the jacket from below and sun at it from above. Neither is fatal in a season; both matter over five.

The answer is shade, and it does not have to be a building. A lean-to, a shade cloth over a rack, the north side of a wall, or simply putting the medium-voltage stock indoors and the building wire outdoors all reduce the rate of loss. Cable that will be sold within a year needs less protection than cable that might sit for a decade, and it is worth being honest with yourself about which one you are storing.

Bend radius, lifting and handling

Every cable has a minimum bend radius, expressed as a multiple of its outside diameter, and it is larger than most people expect for armoured, lead-sheathed and large conductor cable. Bending tighter than that does not usually break the cable outright; it deforms the insulation, wrinkles a shield, cracks a lead sheath or loosens a strand, and the damage shows up later as a failure or as a rejection at a buyer's inspection. On a reel, the barrel diameter is chosen to respect the bend radius, which is one reason you should never rewind cable onto a smaller drum.

Lift the reel, never the cable. Forklift tines or a bar through the bore are the normal way to lift a reel, and the tines must bear on the reel rather than on the wound cable at the edges of the bore. Never lift by a sling around the cable, never drag a reel across gravel with a chain, and never drop one off a tailgate. A dropped reel kinks the layers that take the impact, and those kinks are permanent.

When moving a reel any distance, roll it on its flanges on a hard surface, or use a proper reel trailer. Rolling on soft ground buries the flange and loads the cable.

Yard or shed: what the difference is worth

The table below is a summary of how the same reel behaves in two places. It is written for somebody deciding where to put a delivery this afternoon, which is when the decision usually gets made.

• Medium-voltage and anything lead-sheathed: indoors, or under a proper roof, without exception.
• Bare overhead conductor: outdoors is tolerable if the drum is off the ground and the ends are capped.
• Building wire in factory wrap: outdoors for a season is survivable, but the wrap is the only defense and it tears.
• Anything with a test certificate: indoors, because the paperwork is worth more than the cable if the cable is sound.