Vandenberg AFB – XUMU11-1046B2, T12, Replace Feeder B-3


Schwab Engineering has provided field investigation and prepare construction document preparation to replace 6 mile long overhead feeder B-3.

We have been tasked to replace existing 12KV B3 feeder starting from Substation B, Building 7315, and continuing on overhead poles and underground conduit and cable to Building 1605 toward the end of the airport runway. The existing B3 feeder includes 33,000ft of three-phase overhead conductors and 4000 feet of three-phase underground cable.

The overhead conducts are strung on 220 wood poles each including wood cross arms and required hardware. Individual loads are tapped with fused disconnects and continues through PVC conduit down the pole to underground load circuits. Three SF6 Puffer Switches are utilized to sectionalize the feeder.

The total B3 circuit length is approximately 7 miles. This task includes the B3 feeder existing poles with concrete poles, replacing all wood cross arms to fiberglass cross arms, replacing the existing overhead copper conductors with ACSR conductors, replacing all sectionalizing pole top switches with non-SF6 switches, and replacing all pole hardware with stainless steel hardware. The new poles and conductors will be relocated where possible to facilitate future maintenance.