A covered conductor costs more per kilometre than a bare conductor of the same core. Whether the line costs more over its life depends on every other line in the budget: outages, vegetation clearing, maintenance visits, pole and cross-arm hardware and the cost of the alternatives. This worksheet lists the variables a utility or consultant should record so the comparison is made on the same basis for each option.
APAR’s covered conductor page presents the product as a lower-cost alternative to underground and HTAB cables and notes that a smaller phase-to-phase distance can reduce tower-related costs. Those are the claims to test with the utility’s own figures.
The comparison formula
For each option over the same study period, record: initial cost + (expected outages per year x cost per outage x years) + (annual maintenance and vegetation cost x years) + (cost of repair after faults) + end-of-life cost. The option with the lowest total, using the same period and discount rate for all options, is the lowest lifecycle cost. A unit of currency saved on supply and installation is not a saving if it is paid back in outages.
| Cost line | What to record | Where the figure comes from |
|---|---|---|
| Conductor supply | Price per kilometre for each option, same core and size basis | Quotations |
| Accessories | Clamps, connectors, arc protection and any extra hardware for each option | Quotations and bill of materials |
| Poles, cross-arms and insulators | Whether existing hardware can stay, and any change in phase spacing | Site survey and line design |
| Installation | Stringing labour, shutdown days, traffic or crossing permits | Contractor estimate |
| Outages | Faults per kilometre per year by cause: trees, birds and animals, conductor clashing, other | Utility fault records |
| Cost per outage | Lost sales, crew call-out, penalties and repair materials | Utility finance and operations |
| Vegetation management | Clearing cycles and cost per cycle for the route | Utility maintenance records |
| Inspection and maintenance | Visits per year and cost per visit | Maintenance plan |
| Right of way and permits | Any change in corridor width or clearance requirement | Route survey |
| End of life | Removal and scrap value | Contractor estimate |
Rules for a fair comparison
Use the same route, the same study period and the same discount rate for every option. Take outage counts from the utility’s own fault records for the feeder, not from a general figure. Cost the underground option with trenching, reinstatement and joints, because the cable price alone understates it. Where an assumption is uncertain, record the range and calculate the result at both ends.
The site survey checklist lists the route data that feeds this worksheet, and the fault causes chart shows which outage causes each conductor type addresses.