January 2012 Capital Investment - National Grid

Exhibit ___ (EIOP-19)Page 100 of 684Conductor ReplacementVarious projects are planned which will replace “small” (< #2 AWG) copper, copperweld,amerductor and aluminum conductor.The Company stopped installing #4 and smaller copper primary wire sometime prior to1953. This makes the small wire population at least 58 years old (some of the oldestoverhead energized equipment in service on the distribution system).Drivers:In the course of this 50+ year service life, the average conductor will have lost some ofits tensile strength due to loading conditions and elongation during splicing followingemergency service restoration. This loss of tensile strength increases the likelihood ofconductor breakage during an interruption which involves physical contact with theconductor. Interruptions involving broken conductors typically result in longer servicerestoration times. With each successive interruption the ability to restore service quicklyis deteriorated. This loss of tensile strength is especially significant during a stormsituation where the wind and/or ice/snow loading on the conductor will be higher thanduring clear conditions. These projects will systematically identify and replace the smallwire.Customer Benefits:Replacing the “small wire” population will improve customer level reliability by reducingthe frequency and duration of localized interruptions.Replacement will also improve voltage performance, especially on those circuits havingin excess of two miles of conductor.2011 to 2012 Variance:The projected investment is shown in the table below. These projects were not funded inthe 2011 CIP.Table IV-18Conductor ReplacementProgram Variance ($millions)CIP FY12 FY13 FY14 FY15 FY16 FY17 Total2011 - - - - - - -2012 - 0.9 - 1.5 1.5 0.5 4.4IV-24 24101