Picture of wires on a telephone pole.

Partial undergrounding puts only the high-voltage electrical wires, 1A and 1B, underground. The low-voltage electrical wires, 2, transformers, T, cable-TV wires, 3, and telephone wires stay up on the utility poles. There are no telephone wires on the pole pictured. Telephone wires are located low on the pole, near the cable-TV wires.

Only the high-voltage electrical wires require the 10 feet of clearance from tree branches. Only the high-voltage wires cause trees to be pruned into the V-shape. Only the high-voltage electrical wires prevent planting and replanting of canopy trees under the wires.

Partial undergrounding costs only 1/8 to 1/4 the amount of full undergrounding. Partial undergrounding also eliminates the need for the severe V-shaped pruning of trees under utility wires both on the street terraces and on private property.