Final answer:
The statement is false. High-voltage wires on transmission towers are held by insulating connectors but are not wrapped in insulating material, as the air acts as an insulator at high altitudes and the cost of insulating such long distances would be impractical.
Step-by-step explanation:
The statement that high-voltage wires connected to tall metal-frame towers are held aloft by insulating connectors and are wrapped in an insulating material is false. High-voltage transmission lines are indeed held aloft by insulating connectors to prevent the electricity from grounding through the towers. However, unlike lower voltage wires in residential areas, these high-voltage wires are not wrapped in insulating material. This is because the air surrounding the lines acts as a sufficient insulator at the high altitudes where these wires are situated, and the spacing between the wires is enough to prevent arcing at high voltages. Additionally, insulating such high-voltage lines would be impractical and extremely costly due to the sheer length involved and the high stresses they encounter.