When are bolted connections permitted in electrical work?

Bolted connections in electrical work are permitted when wires are not under tension primarily because this ensures the connection remains secure and reliable without the risk of mechanical stress impacting the electrical integrity. When wires are not under tension, bolted connections can effectively hold the wires together without the additional forces that could cause loosening or damage over time. This stability is critical in maintaining proper electrical conductivity and preventing failures in the system.

In contrast, when wires are under tension, bolted connections may loosen, leading to increased resistance and potential overheating. Similarly, insulating materials or different material types can introduce complications, such as varying thermal expansion rates or inadequate electrical characteristics, affecting the overall safety and performance of the electrical system. Therefore, bolted connections are ideally used in scenarios where stability is assured, ensuring safety and functionality.