Previously, I had posted regarding a job I was heavily considering as it had some career relevance. Currently I am applying to another institute that is partly affiliated with the institute that had given the previous job offer. In this case, is it worth contacting the HR person from the previous job offering, even though the two jobs are essentially at different locations and the HR person could be different this time around?
Get in touch with them
How helpful this will be would vary depending on procedures to picking candidates at the company, but the friend in HR I just asked this question to said that it could be useful.
If they previously made you a job offer, then they already vetted you as a candidate. The other HR person will probably prefer to just search for your name rather than sift through piles of garbage applications to find a few decent ones.
You will probably still be required to fill out an application, but the recommendation from the other HR person could make it easier to get picked out of the pile.
It could help. But the only thing it might do is get you past the first hurdle.
While you might have been the best candidate for position X based on the batch of applications they received, and filtered; there is no way to know if a different person, filtering a different batch of candidates, for a different position, will even invite you for an interview.
Since the cost in time for you to contact them is almost zero, it doesn't hurt to try.