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MV Circuit Breaker Auxiliary Contacts Versus Spare Contacts
2

MV Circuit Breaker Auxiliary Contacts Versus Spare Contacts

MV Circuit Breaker Auxiliary Contacts Versus Spare Contacts

(OP)
Dear Folks,

May someone please explain to me the difference between MV circuit breaker auxiliary contacts versus spare ones.

I got a little bit confused after looking at the GE-Power VAC PVDB breakers schematics, they list all auxiliary contacts that are equipped with the breaker (for example WBA-1R and WBA-2R as aux. b contact), then they also list WBA-1L and WBA-2L on the same schematic as 'Spare' b contact. Aren't they supposed to be the same ones since they are on the same terminal block!!

I appreciate your help and feedback.

Thanks in advance for your help and best regards  

RE: MV Circuit Breaker Auxiliary Contacts Versus Spare Contacts

Without seeing the schematic, I have a couple of thoughts:
1. Is the contact labeled aux b being used in the schematic versus the one labeled spare b contact not being used?
2. Is the spare b contact actually installed or is it an optional additional contact block that can be installed?

RE: MV Circuit Breaker Auxiliary Contacts Versus Spare Contacts

Normally, the aux contacts labelled "spare" are the ones not being used in the breaker control itself and are available for customer use.

RE: MV Circuit Breaker Auxiliary Contacts Versus Spare Contacts

Google
<ge VAC PVDB breakers>
Check
www.geindustrial.com/publibrary/checkout/38652.30055.14248.60209/PDF/GET-6600F6.pdf -
This breaker appears to be supplied with standard aux. contacts. Optional extra aux. contacts are available.
However from your description of the nomenclature, I suspect that contacts WBA-1R and WBA-2R are used in the factory wiring scheme and are mounted on the right hand side of the breaker.
WBA-1L and WBA-2L are probably mounted on the left side of the breaker.
Another possibility is that the contacts listed as aux. are wired to the terminal block and the contacts listed as spare are not wired to the terminal block.

RE: MV Circuit Breaker Auxiliary Contacts Versus Spare Contacts

"Another possibility is that the contacts listed as aux. are wired to the terminal block and the contacts listed as spare are not wired to the terminal block."

Waross, I am 99% sure that this is correct, spares are unused aux contacts used for available options not supplied with this model.

RE: MV Circuit Breaker Auxiliary Contacts Versus Spare Contacts

A spare contact is a contact from *something* that is not used.  It may or may not be from a breaker auxiliary contact.  There are other devices within a breaker cubicle that might have spare contacts, such as the limit switch that indicates if the breaker is racked in or out.

Saying you have a spare contact says nothing about the function or logic behind that contact.  

If the GE drawings shows some as spare and some are not called out as spare, it may be that these contacts are already being used in the internal control circuit for the breaker control.  Just because the contact is brought out to a terminal block does not mean it is available for your use.  

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