Replacement cable has three wires old one had two

[woodman-46]

Hi,
I posted a message regarding how to replace a cable in machine I have . Got some helpful advice. I'm posting this under new heading because I didn't want to confuse the issue and hopefully reach out to more people.
I am going to replace the old cable and fitting on the end with a new one of the same spec. Having looked we notice that on the new one there are three wires black, grey and brown but on the old one there are only two black and grey.
What would be the reason for the brown one, is it an earth? Why would that not have been on the old one ?
Thanks

 

[ericmark]

I will guess normally open, normally closed, and common, and last switch only had normally open and common, but quick test with multi meter will confirm that.

 

[woodman-46]

Thanks for your advice. I checked the old cable and the brown cable had been shipped short and not used.