These typically use oil, air, vacuum or SF6 gas.

Disconnect switches are installed in substations to isolate lines to be worked on.

Wood structures remain popular for transmission lines with operating voltages of 345kv and up.

Fill in the blank: _______ is commonly used to identify lines that typically operate at lower voltages, deliver to the distribution sub.

Fill in the blank: These are chosen based on voltage of the line, the right of way size, geographical terrain, and size of conductor: _______.

Fill in the blank: The term _______ is used for lines that deliver to the distribution sub and operate at lower voltages.

True or False: Transmission lines with operating voltages of 345kv and up commonly use wood structures.

These directed buried structures have a longer life span compared to wood poles.

Insulators must insulate the line and have the strength to support the conductors.