ADSS Splice Slack: What Belongs in the Ordered Length?

Direct answer: account for each end, not a blanket percentage

For a complex aerial route, the ordered ADSS length should follow an approved cable-length schedule that separately identifies the route basis and every additional allowance. At each splice, check the incoming and outgoing cable ends independently. A map distance does not show whether either end can reach the agreed working position or whether the completed reserve can be stored. This guide concerns that splice-level purchasing check; it does not calculate sag or specify a safe installation method.

Start with the splice drawing and its revision

Give each splice location an ID and name the cable section approaching it from each direction. Record the attachment point, closure position, intended work position and access constraints. The responsible designer and installer should confirm the actual cable path between them. A vehicle parked farther from the pole, a closure moved to another support or a revised access arrangement can change the required tail without changing the mapped line distance.

Distinguish access length from the reserve left in service

Cable needed to reach a temporary splicing position and cable retained for future access may overlap physically. Do not automatically add the full amount of both. Ask the installer to show what is consumed in preparation, what returns to the permanent closure location and what remains stored. Corning's Solo ADSS guidance treats splice position and slack planning together before ordering. Its example lengths are product-specific guidance, not a universal allowance for UKCC cable or your project.

Make the purchase calculation auditable

Use separate schedule fields for the approved installed cable path, splice-end allowance at each end, other justified installation allowances and the final ordered length. State whether the base path already includes a downlead or reserve; each physical length must be counted once. The design team supplies the geometrical and mechanical basis. Procurement reconciles the fields and agreed tolerance rather than converting a horizontal map distance to cable length using an unsupported percentage.

A simple example of a double count

Suppose a hypothetical schedule already contains a 20 m end allowance comprising 12 m of access path and 8 m retained reserve. Adding another 8 m under 'maintenance slack' would count that same reserve twice. These numbers demonstrate bookkeeping only: they are not recommended lengths, a UKCC specification or a record of a supplied project. Conversely, an allowance entered for the incoming cable cannot automatically cover the outgoing cable supplied on a different drum.

Check that the planned reserve has somewhere to go

Before approving an extra length, identify the storage arrangement and confirm it with the cable and hardware requirements. The review should cover the actual finished cable, permitted bend limits, support and access for later work. More cable is not automatically better if the proposed storage is unsuitable. Keep work near power infrastructure, support loading and clearances with the qualified project team; the buyer's reserve schedule is not an engineering approval.

Freeze the schedule, then control changes

Attach the approved schedule revision to the order and drum assignment. If the closure, working position, section boundary or cable construction changes, ask which entries must be reviewed before cutting or dispatch. A spare drum elsewhere on the project does not cure a short continuous section without a new splice decision. Resolve the affected section explicitly instead of increasing every drum by the same amount.

What the supply review can establish

UKCC can review the requested ADSS construction and delivery lengths against the information submitted for quotation. The buyer should request confirmation of manufacturing length, tolerance, drum restrictions and the agreed inspection records. The route and splice arrangement still belong to the project designer and installer. The cover is a cable-library reference, not evidence that this splice layout has been built or approved.

FAQ: Is there a standard percentage for splice slack?

There is no project-independent percentage established by this checklist. Obtain the actual end paths, work arrangement and reserve requirement, and reconcile them against the approved schedule.

FAQ: Should both drums include an allowance at one joint?

Review each cable end separately. Both may need a tail, but the required path and retained length can differ. Label the two entries so one allowance is neither omitted nor copied twice.

FAQ: Can unused reserve compensate for an unapproved route change?

Not automatically. The responsible team must review reach, remaining reserve, geometry and storage after the change. Do not release an improvised cut or splice solely because spare metres appear available.

Splice-end length ledger

Before releasing the drum schedule

1. Identify each splice and the two approaching cable sections.
2. Confirm drawing, work position and closure location revisions.
3. Separate base path from additional end allowances.
4. Show overlaps between access tails and retained reserve.
5. Obtain approval for the storage and handling arrangement.
6. Match final lengths to drum assignments and resolve open changes.

Related route and supply information

• ADSS cable reference
• Whole-route segmentation and drum planning
• UKCC factory and inspection information

Installation background — use project-approved values

• Corning Solo ADSS guidance, section 4: splice locations and slack planning