Electronic gate on Shabbat
Is it permissible to go in and out of a Chabad House on Shabbat through an electronic gate/door in a place where the Chabad House has it for security reasons, and it is manned by a Gentile guard who operates it?
Answer: If it is for an important matter like prayer, learning, attending a Shabbat meal or even sleeping in his home and similar things, it is permissible.
If the Gentile is able to operate the gate/door manually, it is permissible to go in and out when he presses the button even if not for the abovementioned reasons.