Which type of circuit breaker is used for isolating circuits without connecting them in parallel?

The correct answer pertains to tie circuit breakers, which are specifically designed to isolate electrical circuits without connecting them in parallel. The primary function of tie circuit breakers is to manage load distribution and ensure safety by providing a means to disconnect sections of electrical systems while preventing unintended connections that could occur if circuits were tied together.

Tie circuit breakers allow for the separation of different sections of a power distribution system, facilitating maintenance, troubleshooting, or isolation of faulty components without affecting the overall operation of connected circuits. This is important in ensuring that other parts of the system can continue operating even when one segment is offline for repairs or upgrades.

Other types of circuit breakers, like single pole and double pole breakers, are designed primarily to provide protection to single-phase and two-phase circuits respectively, but they do not serve the same function in terms of isolation without the risk of connecting circuits in parallel. Residual current devices (RCDs) are intended to provide protection against electrical shock by detecting imbalances in the electrical current; they are also not designed for isolating circuits in this manner.

Therefore, tie circuit breakers are uniquely suited for applications where circuit isolation is necessary without the risk of unintended parallel connections.