THE UNDERGROUND INSTALLATION OF UTILITIES 



365 



The progress in reducing the differential in cost has been from 

 $450 per lot in 1950, to $280 in 1955, to $175 in 1960, and in 1965, 

 to $120. We see a further reduction to a $75-per-lot differential 

 through the adoption of other opportunities for savings which are 

 generally available to us now. I don't want to burden you with 

 technical details, but I am suggesting such possibilities as the use of 

 aluminum low-voltage conductors rather than copper, radial laterals 

 instead of loops, elimination of high-voltage switching at each trans- 

 former, more compact and lower-cost transformers, and use of ran- 

 dom lay cables in the same trench. 



TABLE 1 



Typical URD costs 



Variables 



Rocky soil +.$25. 00 



Primary in coilable duct +35. 00 



Secondary in coilable duct +15. 00 



Services in coilable duct +35. 00 



Perimeter instead of back to back layout +75. 00 



Vault mounted system instead of pad-mount +16. 00 



Radial laterals 1 2. 00 



Aluminum low-voltage conductors 11. 00 



Eliminating high-voltage switch 8. 00 



Random lay cables 6. 00 



Low cost transformer 6. 00 



URD evaluation: 



Reliability and tree trimming 22. 50 



Eliminating joint pole use 12. 50 



Furthermore, the difference in cost can be reduced again to $40 

 per lot if the utility evaluates less tangible features, such as in- 

 creased reliability, elimination of tree-trimming costs which is a 



