| Alternative | New Constr. cost relationship | Retro Fit Issues | Operational Issues | Impacton Trees | Safety Considertion | Net effect on Reliability |
|---|---|---|---|---|---|---|
| UG, cable plow | 200+ | Entirely new plant including transformer, secondary & services may be required. Impractical in developed areas | Limital application as plant and UG infastructure becomes more complex | None | Elimination of tree as a significant cause of interruption | Highly variable dependent on where cable is plowed in relation to trees root system |
| UG, open trench | 200-400+ *highly dependent on site restoration costs | Entirely new plant including transformer, secondary, services may be required. Site restoration may be a major expense. High level of site disturbance | Excellent opportunity to share expensed with other utilities Joint trench requires high level of coordinations and coopertion. Note: trench excavation may not be utility’s responsibilty | None | Elimination of tree as a significant cause of interruption | Highly variable, dependent on where trench is dug relative to trees root system. |
| UG, wheel trench | 200-300 *highly dependant on site restoration costs | Entirely new plant including transformer, secondary & services may be required. Increased difficulty when significant other UG infrastructure is present | Requires cooperation by gov’t agency w/jurisdiction over streets and public ROW | None | Elimination oftree as a significant cause of interruption | variable, generally low to no adverse impact |
| UG trenchless unguide push rod or mole | 300-400+ | Entirely new plant including transformer, secondary & services may be required | Generally requires significant disturbance at launch & recovery pits. Highly dependant on soil conditions. Pits required at direction changes “pot holes” at utility crossings, (best suited to short runs) Low production rates | None | Elimination of tree as a significant cause of interruption | Little to none provided launch & recovery pits sited properly. |
| UG trenchless guided bore | 200-400+ | Entirely new plant including transformer, secondary & services may be required | Highly dependant on soil conditions “Pot holes” at ulility corssings. Low production rates. Less suited to high plant instensity installations | None | Elimination of tree as a significant cause of interruption | Little to no adverse impact. |
Cost relationship is provided as a general relative cost. No cost units are implied. The intent is to provide a comparative cost reference. All values are stated as related to bare overhead 3 Ø distribution primary (100)