If a gentile comes into a Jew’s home on Pesah with Hames, the Jew is not required to send him out of the home. A common example of such a case is a non-Jewish workman or electrician who comes to do repairs. If he brings Hames food with him, the Jew may allow him to remain in the home, and is not required to ask him to leave. Even though the Torah formulates the prohibition of Hames with the term "Lo Yera’eh" ("it shall not be seen"), the complete phrase is "Lo Yera’eh Lecha" ("it shall not be seen to you"), which our Sages interpreted as referring specifically to Hames which one personally owns. It is not forbidden to have in one’s home Hames owned by a non-Jew, and thus if a non-Jewish repairman shows up in one’s home on Pesah with Hames, he may be permitted to remain.
Nevertheless, it is preferable, when possible, to avoid this situation, as there is the risk that the non-Jew may leave crumbs on the table that may reach one’s food. Furthermore, the Ben Ish Hai (Rav Yosef Haim of Baghdad, 1833-1909), in his work Rab Pe’alim (2:55), cites authorities who held that the aforementioned Halacha applies only to raw Hametz dough. According to these Poskim, although one may allow a gentile to bring dough into his home on Pesah, one may not allow baked Hametz products in his home. It is thus preferable to avoid this situation, and to respectfully ask the gentile not to bring Hametz products into the home. If, however, a non-Jewish worker did bring Hametz into the home on Pesah, no violation has been committed, and the Jew should simply clean and ensure that no crumbs were left.
Summary: If a non-Jew will be coming to one’s home during Pesah, such as a workman who comes to do repairs, it is preferable to respectfully ask that he does not bring Hametz into the home, but strictly speaking, the non-Jew may be allowed to enter the home with Hametz, as long as one ensures to remove any crumbs that are left.
