is the conditionnel only after the "au cas où"

Question

J'en ai racheté, juste au cas où.this is not in conditionnel But this is:Au cas où vous auriez faim, je vous ai fait un sandwich.

Accepted Answer

Yes, the conditional is used in a clause that follows ‘au cas où’ - this is noted but not overly emphasised in the lesson. In the first example, there is a completed action done ’‘just in case’ of something that is not expressed eg I bought some more (umbrellas), in case “it rains” - au cas où il pleuvrait. 
With the second example, expressed as an incomplete sentence, as is common in speech - ‘je vous ai fait un sandwich, au cas où’.