At 345 kV a figure of ten times the cost of an equivalent overhead line is quoted for average suburban areas in the U. S. A., this ratio decreasing with lower voltages.

• 在美国一般市郊地区,引证的数据表明345kv的地下输电的等值成本为架空线路成本的10倍。电压低,此倍数可降低。