Tangible things occupy the days of most building managers in New York City. Hot water, floods, bugs, rent checks and so on.

But last week, newly added to the tenant issues facing building managers like Harold M. Jacob, who runs a co-op on the Lower East Side where Orthodox Jews inhabit a substantial portion of the 2,500 apartments, was this almost ontological question:

Does that elevator “know” how many people are on it?

The question is at the core of a ruling issued by a group of prominent rabbis in Israel on Sept. 29 that seems to ban the use of many so-called Shabbos elevators: elevators fixed to stop on every floor from Friday evening until Saturday evening so that observant Jews do not have to press any buttons.

Since the 1960s, when high-rise apartment buildings became ubiquitous, the Orthodox rabbinate has made such elevators one of the few exceptions to Talmudic rules prohibiting 39 categories of activity on the Sabbath, including manual labor or the use of electrical devices. Like flipping a light switch, pressing an elevator button is considered the use of an electrical device.

“Are you sure that’s what it said?” Mr. Jacob asked a person on the other end of the phone line the other day, sitting at his cluttered desk in the management office of Cooperative Village, the co-op he is in charge of. “It can’t be used?”