What is one significant use of PCBs in electrical applications?

Polychlorinated biphenyls (PCBs) were widely utilized in various electrical applications primarily due to their stability and effectiveness as insulating materials. In the context of motors, transformers, and cables, PCBs served as great insulators, helping to control electrical currents and prevent unwanted leaks or short circuits.

In motors, they provided robust insulation that could withstand high temperatures and electrical stresses. In transformers, PCBs were used for insulating and cooling due to their high dielectric strength, which is crucial in preventing electrical arcing. Cables, often exposed to various environmental conditions and electrical demands, benefited from PCB insulation to maintain performance and safety.

Thus, considering the versatile utility of PCBs in all these applications, stating that they are used for insulation in motors, transformers, and cables is accurate, supporting the choice that highlights their significance in all these areas. The presence of PCBs as insulation facilitates safer and more efficient electrical systems, making it a critical aspect of their historical application in electrical engineering.