Identifying wires for XPS3

[Mellowmark]

Take the light, that the switch controls down. See if the white one in the back of the box goes to it. If it does tie a new one on to it and pull it down to the switch, now  you have enough to splice.  Don't worry about the orange one, it is for a different circuit.  Just remember to check the voltage.  Most likely the conduit goes from the switch to the light. If not you may have to open a few more boxes to follow the wire. The High voltage scenario is very slim in a residential application. 
 
If that wire is grey and not white then beware you may have a 277volt circuit.  brown orange and yellow wires with Grey neutrals  are supposed to be 277/ 480 volt colour code and black red blue and white are 120 /240 colour code. only until recently has this practice become mandatory and we electricians just did it for ourselves. Some guys did there Own thing, Which is what you probably have there.   

I Hope this helps     You too Knightrider.   .
Grey is a neutral wire also
sometimes guys will use different colours  just to make it easy to Identify

[Brian H]

Never saw a Grey as a neutral, but will keep it in mind for future use.
Maybe in my next home. I have two wire Romex with NO bare ground wire in the sheath.

[Mellowmark]

Yeah you won't see grey wires in a home, normally. It was leagal. But really only used for industrial or commercial installations. And now only leagal in a 277/480 volt system.  That way you know you have the high voltage when you see the different colours.

[Knightrider]

Thanks MellowMark!!!

I thought gray was a neutral color!