Circuit breaker Auxillary switch.

The auxilary switch is usally used for the control circuit for the equipment that it serves. It is also used for monitoring to verfy the position of the breaker. They usally have a max rating of 240V @ 10A

So when you open the power circuit it also opens the control curcuit.

It could be what sparky says, but I also think it might just mean that in addition to the primary on-off switch on the equipment there is an auxilary or alternative way to turn your equipment on or off using the circuit breaker.

Previous answers cover this well. Either use the aux contact for a circuit to the PLC or whatever control you have to monitor on/off state, or as a means of activating associated equipment that should be on when the equipment on the breaker is on, or to activate a pilot light, etc. Therefore, summing up:

1. it is a monitor circuit

2. or a replacement for a second switch

In Europe, you will find control systems using circuit breakers that have a second set of contacts which carries the same current as the main contacts. They are similar to the common 2-pol breaker, but the second pole does not have the ability to trip the breaker. The second set is used to open the current return path on the device or circuit being protected.

Auxillary switch of circuit breaker means the switch which contains contact(NO and NC) of circuit breaker. This switch is not electrically operated. This switch is mechanically operated and coupled with moving contact of breaker or we can say mechanical mechanisum(making breaker ON and OFF) which changes the NO and NC contacts of this switch into NC and NO respectively.

These contacts are used for external use(protection of closing coil, triping coil, other protections, indications either the breaker is ON or OFF or other interlockings).

It is located at different places for different type of breaker and for different make But this switch is coupled with mechanical mechanisum which make the breaker contact to close or open.

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thank you....CR4

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yes,whatever u explained is right,its just a operating mechanism as per the position of main breaker.Its just a mechanically coupled operational switch which closes and opens the contacts as per the main breaker mechanism,,,its contacts will be used in the control logic of main breaker for safe operation

GA for pwr2thepeople.

There are two kinds of Aux contacts by the way, those that are operated by the main contact mechanism that follow the open-closed status of the power contacts (often called "bell" contacts here in North America), and those that are operated solely by the actual handle mechanism, not the main contacts (called "handle contacts").

The subtle difference is that handle operated aux. contacts do not change state if the breaker trips, only when someone physically moves the handle to the full OFF position (or On, as the case may be). One purpose of this difference is when you want to ensure the safety of opening an enclosure, because a breaker in the "Tripped" position may be more likely to have a welded contact and not be safe, but the door interlock cannot be unlatched until the breaker handle is moved to OFF and a qualified technician will know the possibility of the danger. It also can be used in conjunction with the Bell contacts to discriminate between a trip and someone just leaving the breaker Off.