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Switch/Relay Contact Naming Convention

Switch/Relay Contact Naming Convention

I recently was told by someone from Schneider Electric that there was an IEC standard that covered the standard names given to contacts for relays, switches, etc. Unfortunately, he did not remember the IEC document number. I am speaking of the names like A1, A2 for the contact terminals.

Does anyone happen to either know the number/title for an IEC docuemnt that covers this, or any other resource.


RE: Switch/Relay Contact Naming Convention

You might look at IEC 60439 and IEC 60947 as a couple of possiblilities. While looking I found this document which provides a comparision of NEMA and IEC motor starters:

It mentions the numbering system only briefly, but it might provide something useful.

If we learn from our mistakes I'm getting a great education!

RE: Switch/Relay Contact Naming Convention

Very good material, ScottyUK, thank you. morex, according to me fig.1 is exactly what you need. I would add just one point - change-over contacts are marked like that: 11-14 is NO and 11-12 is NC contact.  

It may be like this in theory and practice, but in real life it is completely different.
The favourite sentence of my army sergeant

RE: Switch/Relay Contact Naming Convention

And, to expand on that, 13-14, 23-24 etcetera are NO contacts on a contactor, while 11-12, 21-22 etc are NC contacts. 15-16, 25-26 and higher are special contacts, usually early break, early make and other special functions. Haven't been able to find the documents.

Gunnar Englund
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

RE: Switch/Relay Contact Naming Convention

Thank you ScottyUK and all for your comments. They are helpfull.

RE: Switch/Relay Contact Naming Convention

It bears mentioning that technically, there are semi-official standards in N. America as well. We just tend to be an independent bunch and ignore stuff like that...

RE: Switch/Relay Contact Naming Convention

I think that in N. America the semi-official standards you speek of are actually IEEE standards.

So is there a guide on converting standards from IEEE to IEC?


RE: Switch/Relay Contact Naming Convention

It sounds to me that he was referring to BS EN/IEC 61346 (Industrial systems, installations and equipment and industrial products. Structuring principles and reference designations).

This gives a code letter for each type of electrical equipment, e.g. K = relay/contactor, R = Resistor, S = switching devices for control circuits etc.)

I don't think it covers terminal referencing numbers though.

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