Which type of wiring involves twisting two conductors together to cancel electromagnetic interference (EMI)?

The type of wiring that involves twisting two conductors together to effectively cancel electromagnetic interference (EMI) is balanced twisted-pair. This design utilizes the principle of balancing, where each conductor carries the same signal but in opposite phases. When EMI affects the wires, it is applied equally to both conductors. Because the two conductors are twisted, the interference induced on both wires tends to cancel each other out when the signal is received at the destination.

Twisted pairs are commonly used in telecommunications and data networking due to their ability to maintain data integrity over longer distances compared to other types of wiring. The twist in the wire creates a consistent spacing and orientation of the conductors, which helps to further minimize interference from external sources. Balanced twisted-pair cables are foundational in various networking standards, reinforcing their significance.

Other options, such as unbalanced-pair wiring, do not utilize this balanced approach and are more susceptible to EMI. Shielded twisted-pair does provide additional protection against interference but combines both shielding and twisting. Open wire lacks any such protective measures or twisting, making it the least effective regarding EMI cancellation.