It is correct to ask only about non-Jewish workers, as calling Jewish workers would clearly violate lifnei iver.[1] Obviously, your non-Jewish workers would not be sinning by taking your call. However, would you be violating amira l’nochri[2] by, in effect, asking them to take the call?
One might claim that since at the time you want to talk to the non-Jew, it is not Shabbat for you, the laws of Shabbat, including amira l’nochri, do not bind you. However, we find that you are forbidden to ask a non-Jew before Shabbat to do work for you on Shabbat, even though your involvement in the matter was not on Shabbat.[3]
In BeMareh HaBazak,[4] we dealt with this issue by seeing whether any of the three possible reasons for the prohibition of amira l’nochri applies in the case at hand. One reason is that it violates the rule that one may not discuss matters that pertain to activities, including melachot, [5] that are inappropriate on Shabbat.[6] This issue stresses the Jew’s involvement and is thus not pertinent here. After all, your call, which you make after Shabbat from your perspective, is appropriate for you.
A second reason is that when a non-Jew does melacha at a Jew’s behest, it is, on a certain level, as if the Jew is doing it through an agent.[7] This also should not be a problem, as even if you were to do the melacha yourself at the time in question, it would be permitted, as Shabbat is finished for you.
The Rambam[8] provides another rationale for the prohibition of amira l’nochri: “so that Shabbat will not be light in their eyes, and they [the Jews] will come to do it themselves.” This also seems not to apply, as one who waits until after Shabbat to ask a non-Jew is not treating Shabbat lightly.
Despite all of this, Rav Zilberstein[9] entertains the possibility that it is forbidden for a Jew to ask a non-Jew to do melacha for him when it is Shabbat only in the non-Jew’s location. He tries to prove that a non-Jew’s work on Shabbat is considered “breaking Shabbat” (albeit in a permitted manner). His contention is based on the halacha[10] that one may not make a beracha at Havdala on a candle that a non-Jew lit on Shabbat because it is a “light that did not rest.” Rav Zilberstein does not fully clarify his reasoning, but one can explain the possible stringency in two ways: One way is based on the rule that the Rabbis forbade asking a non-Jew, even before Shabbat, to do melacha on Shabbat. Our case may fit that prohibition’s parameters, and it may not make a difference whether or not the prohibition’s logic applies. (One of the most complicated issues in halacha is if and when a rabbinic injunction that was made under certain circumstances applies to cases where the original logic doesn’t apply.) Another explanation may be based on the Rambam that treating Shabbat lightly, by having a non-Jew do work on one’s behalf, can lead to real violations. It is possible that as long as it is Shabbat in the non-Jew’s place, there is an element of taking lightly.
In the final analysis, there is a consensus amongst recent poskim that our case is permitted[11] because the logic of the prohibition of amira l’nochri does not apply. We offer one proviso, however: If it is publicly known that yours is a Jewish-owned business, then even non-Jewish workers should not do work on the premises when it is Shabbat locally, even if it is not Shabbat for you.[12] This is because work being done at such a business[13] gives the wrong impression to the public (marit ayin) since, for the local populace, it is Shabbat.