What is the component called that allows switching between two power sources so that only one of them can be used at a time?


A transfer switch allows you to switch between two or more power sources.

An Interlock is a device that prevents a breaker or switch from being toggled. In the situation of two power sources, an interlock is used to allow only one power source to be on at a time.


Unless it is totally safe for the two supplies to be connected together, to avoid risks of a faulty switch it is usual to use a 'change-over panel', containing two contactors, where either one being closed opens a switch to prevent the other closing electrically (electrical interlocking), and often a lever or system of levers between the two also peventing both being closed at the same time (mechanical interlocking)

  • 3
    So an interlock or transfer switch, just like the previous answer given almost TWO YEARS AGO. – Speedy Petey Aug 3 '16 at 16:16

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.